Standup Zone Forum

Hi guys,

Here's something for you to chew over when you're on your lunchbreak. A roadmap for a bit of scientific testing for race boards.

https://www.supboardermag.com/2016/06/21/board-testing-101-how-to-find-out-what-board-is-fastest-for-yo/

What are you using to count strokes?

I have a Naish Maliko and an NSP Ocean, both in 26 wide on hand. I'd be curious to see the difference between the planing hull design and the pure round hull soft edges hull design. They feel very different.

Quote from: yugi on June 21, 2016, 05:18:00 AM
What are you using to count strokes?

I have a Naish Maliko and an NSP Ocean, both in 26 wide on hand. I'd be curious to see the difference between the planing hull design and the pure round hull soft edges hull design. They feel very different.

I used a SUP Speedcoach 2 for this study to provide the stroke data. However, I've also used a Vaaka cadence sensor in the past successfully too.

Very interesting. Have you performed any formal statistical testing on your data? It would be interesting to see the differences in variance between the two boards.

The main flaw in your experimental design of course is that you were not blind to which boards you were on. So this could be a placebo-type effect: you believed that the flat water board would be faster, and so this changed some subtle aspect of your technique or effort, and that is what caused the effect. In medicine, placebo- type effects can often be more substantial than actual treatment effects. It is particularly problematic in this respect that you did not also collect physiological measurements (eg. HR) and perhaps also physical ones using e.g. a strain gauge on the paddle.

But I'm sure that as a scientist you will already appreciate this. Do you have an idea of how you will deal with this criticism from the referees when you submit it to a scientific journal as you mentioned?

Of course, what we all want to know now is whether the all-round board is faster in the conditions it was designed (at least partly) for. Measuring performance differences in the sea across a variety of conditions is a substantial scientific challenge, and you may need other ways of doing the comparisons, perhaps.

It's great to see someone taking the time and effort to do this. It's extremely difficult to get scientifically convincing results from board comparisons - which is why so few people have tried.

Quote from: Area 10 on June 21, 2016, 08:04:15 AM
1) Very interesting. Have you performed any formal statistical testing on your data? It would be interesting to see the differences in variance between the two boards.

2) The main flaw in your experimental design of course is that you were not blind to which boards you were on. So this could be a placebo-type effect: you believed that the flat water board would be faster, and so this changed some subtle aspect of your technique or effort, and that is what caused the effect. In medicine, placebo- type effects can often be more substantial than actual treatment effects. It is particularly problematic in this respect that you did not also collect physiological measurements (eg. HR) and perhaps also physical ones using e.g. a strain gauge on the paddle.

But I'm sure that as a scientist you will already appreciate this. Do you have an idea of how you will deal with this criticism from the referees when you submit it to a scientific journal as you mentioned?

3) Of course, what we all want to know now is whether the all-round board is faster in the conditions it was designed (at least partly) for. Measuring performance differences in the sea across a variety of conditions is a substantial scientific challenge, and you may need other ways of doing the comparisons, perhaps.

4) It's great to see someone taking the time and effort to do this. It's extremely difficult to get scientifically convincing results from board comparisons - which is why so few people have tried.

Great reply - thank you. I've numbered your excellent points above and will attempt to address them here:

1) Yes I have. The article I wrote was for a general audience so I left out a considerable amount of statistical material that only would have confused (or frankly just bored) the hell out of most people. I did have extra stats though (such as the coefficient of variation to show how stable the tests and the boards were), t tests (to show that both boards were significantly different from each other) and a few other bits and pieces. My paper will obviously include them but this articles intent was to encourage people that a. kit choice was important and b. you can do it yourself if you make the time. Granted, a lot of this hangs on how important you believe stroke count is but HR is no good in shorter test intervals like this but if you lengthen test intervals out (and Larry Cain has done this) you might be able to use it but then you won't have a decent sample size as it will be too fatiguing. I'm hoping the margin of errors I included allay many of these concerns but for what it is worth, my coefficient of variation (defined as Standard deviation divided by the mean X 100) was no greater than 0-3% on everything (test repeatability and the boards speed and stroke data) bar the slowdown tests (which did push up towards 10 - still not bad but conditions really matter for those).

2) Yes - placebo is a huge issue generally. However, my paper will be focusing on the robustness of the tests themselves rather than worrying about the performance of boards A and B specifically. I would make the case that the statistical analysis and results are strong enough that it would be hard to be affected by placebo - especially the hydrodynamic slow down tests whereby you can't really influence the results anyway as you've just put Archimedes and Newton in the driving seat.

3) Between you, me and the internet, I suspect if you tried these tests in the more typical conditions of a flatwater race (which would have seen a little more chop than I tested in), the gaps between the two boards would come down. Plus I also suspect (and there is research in other sports like K1 to support it) that bodyweight is going to play a huge part in craft performance. It all adds to that people need to test themselves using boards and conditions that suit them. I would also recommend being aware of the test limitations. For example, the slow down tests (test 3 in the article) are fast and easy but used on their own do not consider the nuances of your stroke and if your board is slightly under volume, will perform badly in that one whereas it might do really well in others when the speed (and therefore the resulting lift) might well let it shine.

4) It is hard but not impossible. It's something I'd need to work upto and figure out the right test interval and environment to do so. The margin of errors will increase and its quite likely that as board design becomes a race of diminishing returns, the gains will be swamped by the margin of error. Bearing in mind I've only been paddling a couple of years, I was surprised how statistically repeatably I was able to perform in these trials to start with. I see this as a starting point for other ideas i have in mind.

Your "Test 2" is really interesting. I wonder, though, about the assumption that stroke rate is an adequate proxy for power applied. When you paddle at different speeds to generate the data for that graph, how do you ensure that you're varying only stroke frequency and not force per stroke? I know from technique drills and such that I can change speed independently of stroke rate by altering the reach and power of each stroke.

Quote from: FloridaWindSUP on June 21, 2016, 09:55:36 AM
Your "Test 2" is really interesting. I wonder, though, about the assumption that stroke rate is an adequate proxy for power applied. When you paddle at different speeds to generate the data for that graph, how do you ensure that you're varying only stroke frequency and not force per stroke? I know from technique drills and such that I can change speed independently of stroke rate by altering the reach and power of each stroke.

Yep, you're absolutely right - stroke rate is only part of the power equation and doesn't account for the torque you're producing. Its good practise to use at least two metrics when judging performance (with one acting as the variable and the other as a governor). Power output would be the gold standard but until that arrives its a choice between heart rate or stroke rate. I actually use both in my everyday training but as far as the decision to use it for equipment testing purely came down to stroke rate being the only one you could make statistically viable (to get the right number of runs and not require a longer interval) and secondly that there was published research already (granted in other paddle sports but not SUP) that had reliably indexed stroke rate to work intensity. However, I would openly agree that cadence has limitations when the force data is not able to be recorded. It's also possible that if you tested a board that was beyond your paddling capabilities, this could also sour the results. With all of this in mind, I'd combine tests 1 or 2 but then reinforce that with test 3 (which ignores stroke rate entirely) to likely give you a greater chance you know what is faster.

It's all a work in progress and something I can build on. Thanks for your feedback - its very useful.

UK- I'm not a scientist so I'll need to think a bit harder about this to really appreciate everything that is actually going on and all the underlying decisions and processes but it is very interesting stuff. One thing I do takeaway is that the robustness of the design of Test 2 and its results quiets many of my worries about the inability to hold constant all the variables involved in paddling. It'll be looking forward to see what happens once you can measure power at the blade and hold it constant for testing purposes.

An unrelated question: A large part of the game in SUP is to limit the deceleration between strokes. Have you ever had similar concerns about cycling on the road, or would you think that the issue so minor there as to be practically meaningless?

Quote from: SUPJorge on June 21, 2016, 01:33:13 PM
UK- I'm not a scientist so I'll need to think a bit harder about this to really appreciate everything that is actually going on and all the underlying decisions and processes but it is very interesting stuff. One thing I do takeaway is that the robustness of the design of Test 2 and its results quiets many of my worries about the inability to hold constant all the variables involved in paddling. It'll be looking forward to see what happens once you can measure power at the blade and hold it constant for testing purposes.

An unrelated question: A large part of the game in SUP is to limit the deceleration between strokes. Have you ever had similar concerns about cycling on the road, or would you think that the issue so minor there as to be practically meaningless?

Yep, this reads as three different tests you can do but actually I did have an ulterior motive when planning it.

Test 1= ascertained the repeatability of my paddling technique at race pace and the repeatability of the boards overall performance. If the results were poor, tests 2 and 3 would be pointless as my underlying scientific method would not be robust and this whole idea would be a failure.This test was a precursor to my preferred strategy of testing boards of tests 2 and 3.

Test 2= to derive a simple method of finding the typical performance of the board across a broader range of speed. The line of best fit is basically the best fit of line to the data. However, for the scientists out there, a polynomial line fitted my series dots with a R squared value of 0.99 (i.e. a near perfect fit).

Test 3 = to test a boards resistant drag by removing the variability of the paddlers technique entirely.

Test 3 won't work in chop but test 1 and 2 might. I do need to try that though and I fully expect the margin of error to increase greatly.

As for cycling, air is nearly 800 times thinner than water and a cadence nearly twice as much as paddling so pedal stroke I would suggest its less relevant. That said, I've personally seen increased resistance to my power output quality when riding on rougher road surfaces when compared to smooth ones (and I time trial at ~85-90rpm and at ~370w for 20 minutes) so its entirely possible there is a small effect. However, I would have to defer to better technical paddlers than I to advise you when it comes to paddling.

Very interesting. A couple of observations off the top of my head. The drag test doesn't seem to specifically include optimum trim. 1. Weight position has a big effect on drag, as does total weight. You might get more conclusive results by stacking a representative weight on each board and winching it through the water with an attached strain gauge, and then moving the weights around to find the optimal trim (lowest force). You could still use coastdown for drag estimate, or just calibrate the strain gauge. You don't need much of a winch, any speed controlled motor attached to a drum reeling light line would do.

You could approximate this by doing your coastdown test in a number of positions. A relatively insensitive test for a factor with a likely narrow range of results, but it might be adequate.

2. I think you really need a power meter. You can get at the power applied by measuring acceleration and total mass, but F=ma assumes we isolate acceleration, and you don't really have a way to do that. Too many other factors acting on the board.  You might consider video as a measure of stroke rate vs. length vs. acceleration. You can certainly measure speed in a video with a calibrated float by doing stop action of the strokes. You might be able to get a relative power number from shaft flex, but it's probably going to be inaccurate as a measure.

Anyway, I'm just spitballing. Your test raises a lot of interesting possibilities. Congratulations.

Quote from: PonoBill on June 21, 2016, 03:01:35 PM
Very interesting. A couple of observations off the top of my head. The drag test doesn't seem to specifically include optimum trim. 1. Weight position has a big effect on drag, as does total weight. You might get more conclusive results by stacking a representative weight on each board and winching it through the water with an attached strain gauge, and then moving the weights around to find the optimal trim (lowest force). You could still use coastdown for drag estimate, or just calibrate the strain gauge. You don't need much of a winch, any speed controlled motor attached to a drum reeling light line would do.

You could approximate this by doing your coastdown test in a number of positions. A relatively insensitive test for a factor with a likely narrow range of results, but it might be adequate.

2. I think you really need a power meter. You can get at the power applied by measuring acceleration and total mass, but F=ma assumes we isolate acceleration, and you don't really have a way to do that. Too many other factors acting on the board.  You might consider video as a measure of stroke rate vs. length vs. acceleration. You can certainly measure speed in a video with a calibrated float by doing stop action of the strokes. You might be able to get a relative power number from shaft flex, but it's probably going to be inaccurate as a measure.

Anyway, I'm just spitballing. Your test raises a lot of interesting possibilities. Congratulations.

Thanks for your useful comments.

1) Yep, optimal trim wasn't pursued as that wasn't the primary aim of the study. This experiment was primarily about establishing whether a scientific method could be achieved or not and to provide some workable examples (notice I kept the board brands and models anonymous too). I did standardise trim between runs by marking foot position on each board to ensure trim repeatability but its entirely feasible that trim could be optimised from where my feet were actually placed and this would change the results. These tests could certainly help do that in the future. Your suggestion is an interesting idea though. I've also seen published research whereby they towed craft behind a speedboat (but off beam) using a cable with strain gauges to measure the resistant force. That could achieve the same as what you're suggesting.

2) Agreed. A power meter is the holy grail (and the best solution) and I wait for the long overdue one to arrive on the market. I'll be the first one there to get my money down when it arrives. In the meantime, we've got to work with what we have available and it was important to me to suggest methods that anyone could do with relatively low-fi equipment.

I think your board test was quite reasonable - and your results seem valid.  We simply paddle around a couple of islands in a triangle course for about 5 miles - measuring 3 split times.  Works close enough for us and we can replicate the results with consistency.  We do account for wind waves and current when analyzing our data.

What we found in these simple timed tests was that - as soon as ripples turned into solid chop - our wider touring board takes over and becomes faster than our race board.  Many tests were done years ago - and were subsequently compared to more recent GPS data and HRM data as well.  The current results reflect a similar pattern to before.

So the fastest board for us was the board that we could paddle consistently using full power.  In our ocean tests - the conditions had the greatest impact - and this affected fatigue and balance the most.  In one instance on a 9 mile paddle on our race board - I had to resort to paddling on my knees - conditions deteriorated so much.  After 7 miles of punishment - just could not stay standing anymore.  My legs were toast from all the balancing.  On a subsequent day was out on our touring board paddling the same course - and was able to easily power along in even worse conditions. 

So for flat water our race board was faster - and for rough water our wider touring board was faster.  Pretty much nowadays we can tell with just a demo how easy a board is to balance on - and how efficiently it paddles.  Probably if we tested these 2 boards under your test parameters - we would arrive at similar plots and conclusions as you.

Nice. 2 different methods come out with smooth consistent results corresponding to the outcome we'd expect (flatwater board optimised for flatwater). Seems to work correctly.

I thought something but didn't answer yesterday, I waited and re-read the test and re-thought it. I think you are making one assumption here. That your blade is slipping. More slippage equates more effort to move craft forward.

You just happened to post this at the same time as the raging discussion (slower is faster thread) on not slipping the blade and on how, if a blade is being well set, cadence should match boat speed. Faster cadence should be on the faster craft. Ideally planted a blade would stroke the same StrokeLength*AmountOfStroks on either craft and difference should be the amount of sweat produced (effort).

You're basically measuring how much the tires are slipping in wet grass as a definition of efficiency of the craft. Isn't it?

Basically you are measuring how efficient a paddler is in one craft against another. I wonder if the paddle slippage assumption is the right one.

Would that Motionize sensor measure more stuff about a stroke to tell us enough more from which we could derive effort?

Would a guy like Tituan, who definitely has minimum slippage, doing this test come up with same results? You should ask him to double check it for you.

Effort would be the right thing to measure once a power meter is available.

I use a straight section of the Hood River, chosen mostly for bank access (laziness trups accuracy) but observing the river grass in this section convinces me that it's pretty straight. No wafting, no turbulence. Then again, I wanted to be convinced. I use a windsufing mast and a strain gauge from a cheap scale. I originally used a digital multimeter to read the strain guage, but decided the scale guts made more sense, the LED and the electronics are mounted on the mast with extension wire to the strain guage. I think I have $29 invested in the whole apparatus. Suprisingly accurate once I added a 3 to 1 force multiplying lever.

I thought about building a drag winch this year for lowball tank testing. We have two perfect places to do it in Hood River, the best is probably Nichols, but the pond inside the Hook would work well too.

I get that you were more interested in establishing a valid methodology than in the nuts and bolts, but I'm biased towards trying to get the tools working well so the data doesn't demand a lot of tweaking. I understand the basics of statiistical validation but I see examples in everyday life where valid numbers deliver invalid conclusions.  The 50 percent improvent that means 1.5 people had a good result instead of 1.

Quote from: Eagle on June 21, 2016, 07:55:24 PM
1) I think your board test was quite reasonable - and your results seem valid.  We simply paddle around a couple of islands in a triangle course for about 5 miles - measuring 3 split times.  Works close enough for us and we can replicate the results with consistency.  We do account for wind waves and current when analyzing our data.

2) What we found in these simple timed tests was that - as soon as ripples turned into solid chop - our wider touring board takes over and becomes faster than our race board.  Many tests were done years ago - and were subsequently compared to more recent GPS data and HRM data as well.  The current results reflect a similar pattern to before.

3) So the fastest board for us was the board that we could paddle consistently using full power.  In our ocean tests - the conditions had the greatest impact - and this affected fatigue and balance the most.  In one instance on a 9 mile paddle on our race board - I had to resort to paddling on my knees - conditions deteriorated so much.  After 7 miles of punishment - just could not stay standing anymore.  My legs were toast from all the balancing.  On a subsequent day was out on our touring board paddling the same course - and was able to easily power along in even worse conditions. 

Thanks for this.

1) From my point of view, I operate from the standpoint of statistical robustness as the bottom line so I personally believe that provided there are enough runs and that people are aware of their margin of error or data variability (an aspect sadly not reported or recorded in pretty much all previous attempts I've read), you could likely average out the chaoticness of a rougher water paddle if you do enough runs. I personally haven't tried it though but at the end of the day, most people won't be as concerned to obtain the same information as I would hold myself to (being an academic and someone who has to publish for a living)

2) Yep, I agree with you. I'd personally like to know what level of conditions would allow my all water board to triumph over my flatwater. That wasn't my aim here but may well form the fundamental part of what I'm going to race on for 2017.

3) I think this is an important point. Because so much of my tests hung on paddle stroke, if the board becomes to narrow to be effective, the results won't be any good (although this would likely be indicated in both the data's variability and margin of error). In that case, try test 3 as that might make any answer more suitable and helpful as your technique and balance improves.

Quote from: yugi on June 21, 2016, 09:37:55 PM
1) I thought something but didn't answer yesterday, I waited and re-read the test and re-thought it. I think you are making one assumption here. That your blade is slipping. More slippage equates more effort to move craft forward.
You're basically measuring how much the tires are slipping in wet grass as a definition of efficiency of the craft. Isn't it?

2) Would that Motionize sensor measure more stuff about a stroke to tell us enough more from which we could derive effort?

3) Would a guy like Tituan, who definitely has minimum slippage, doing this test come up with same results? You should ask him to double check it for you.

Some great points here. I'll try and answer them:

1) Yes, tests 1 and 2 do hang the results on how well a paddler paddles. It basically makes most testing only as good as the paddler is technically. Therefore it's likely that if I'd tests a 21 inch Starboard sprint against a 26 inch board, I would struggle to paddle the narrow one well and would end up with different results to someone like Baxter. However, provided you calculate the run to run data variability and margin of error, that's all that is important to see which board is then best for you. To date, when you look at peoples data online, they do not declare this kind of data so it makes any assessment hazy at best. Test 3 might reduce this issue though.

2) Possibly. I need to look at that - thanks for the suggestion.

3) No, he'd come up with different results as his level of slippage might well be different. However, the bigger issue might well be one of body mass as I'm 93Kg (6ft 3) and he's a lot smaller which will change the hydrodynamic profile in the water, present a smaller aerodynamic body to the wind and then ultimately produce different subsequent results. Contrary to what brands might tell you in the brochures or net, all test results are going to be exclusively relative to the paddler.

It is an attractive option to remove the paddler from the tests altogether (e.g. by using a flow tank), in order to reduce error variance due to paddler differences. However this would be missing a critical point about SUP design and performance. This is that how fast a board is, at least in terms of average speed, is intimately related to how it copes with the forces acting upon it when someone paddles, in particular pitch and yaw. I've seen several raceboards that looked as if they should be fast when static in the water, but showed excessive pitching when the paddler put the power down, with a dramatic effect upon the efficiency of the board through the water. This is also why just letting the board glide while the paddlers stands motionless is also not likely to be a particularly good test of the real utility of a board in a race situation.

Thought about this some more. A video shot from the side of a paddler next to a hundred feet of tape-calibrated PVC pipe (which I happen to have behind my garage) shows both stroke length (from the point the paddle enters the water to the point the paddle exits) and speed. Accurately measure acceleration using an impeller to measure speed at the beginning, middle and end of the stroke. Or use coastdown from max speed to stroke start. Weigh paddler and board. Now you have everything you need to calculate power.

I hope the Speedcoach offers access to raw data. The acceleration and stroke initiation points should be directly readable. We'll see.

Quote from: PonoBill on June 22, 2016, 10:12:58 AM
Thought about this some more. A video shot from the side of a paddler next to a hundred feet of tape-calibrated PVC pipe (which I happen to have behind my garage) shows both stroke length (from the point the paddle enters the water to the point the paddle exits) and speed. Accurately measure acceleration using an impeller to measure speed at the beginning, middle and end of the stroke. Or use coastdown from max speed to stroke start. Weigh paddler and board. Now you have everything you need to calculate power.

I hope the Speedcoach offers access to raw data. The acceleration and stroke initiation points should be directly readable. We'll see.

Yep, that sounds feasible in theory. I look forward to seeing how you get on with trying it !  :)

Quote from: Area 10 on June 22, 2016, 09:14:34 AM
It is an attractive option to remove the paddler from the tests altogether (e.g. by using a flow tank), in order to reduce error variance due to paddler differences. However this would be missing a critical point about SUP design and performance. This is that how fast a board is, at least in terms of average speed, is intimately related to how it copes with the forces acting upon it when someone paddles, in particular pitch and yaw. I've seen several raceboards that looked as if they should be fast when static in the water, but showed excessive pitching when the paddler put the power down, with a dramatic effect upon the efficiency of the board through the water. This is also why just letting the board glide while the paddlers stands motionless is also not likely to be a particularly good test of the real utility of a board in a race situation.

Yep, I agree with you to a point. That's why I offered several tests and would normally corroborate the outcome from one with at least one other. Either way, this only goes to show how any test should be specifically tailored to the needs of what you want to actually find out. The slowdown tests themselves were based on a rowing study (which will have less issue with both pitch and yaw due to its more symmetrical nature). However, if I had two boards and a quick half an hour of testing showed one had significantly more drag than the other, than I feel that would then be worth investigating further. I would doubt (but its not impossible) that a board that has more drag than another is going to be the better board when used in flatwater racing (granted for all-water its often seen) unless you're really going to board design extremes. If I found a board had lower drag but fared badly in other speed tests, I'd see if the balance issue was trainable at my end before rejecting it as a choice.

All in all though, this is kind of the point - test, find stuff out and let it inform your racing choices. There will always be room for improvement when it comes to field testing science but the important thing is to get the initial ideas out there and then have the debate about them. I'm hoping the work I've done might prompt people and brands to see the value by moving beyond just the use of intuition.

I think designers and brands use not only intuition - but direct input from their racers and race results.  Brands say they sometimes design 20+ prototypes before arriving at the end product on the shelf.  The multi-variables of a race or of a DW run seem to make it difficult to get scientific numbers that mean much in the real world.  But nothing ventured nothing gained - as some may say.

I like the idea of towing a weighted board with a powerboat off the beam (away from any boat wake influence) with a strain gauge. This would allow you to venture beyond the millpond and get feedback on how the boards attributes work in a more realistic environment.

It may not be too telling in a small boat, which itself would be impacted by chop and wind...but a larger boat (80'+) could go through a couple feet of chop with impunity and provide a stable enough platform to give some data of value.

It would be interesting to see if this would provide a consistent "first level filter" to separate the sheep from the goats right up front before investing a lot of time in more elaborate testing.

Some racers seem to just go with what the top pros use.  Or what their closest competitors use.  That seems to narrow down their choices close enough straight away.  If they get a "discount" all the better.

For us - we are very happy and content not to be in a SUP arms race.  Serious racing we leave to the really fast paddlers.

But your comment "all test results are going to be exclusively relative to the paddler" does resonate and is valid from our testing as well.  Any board and paddle combo will be best suited if optimized for the conditions and use.  For that reason we have a number of boards and paddles.  Not 100% necessary or even necessary at all - but having the choice does make paddling a lot more fun when you use the right implement for the job.

Yesterday was out on our Dom doing an upwind DW in 15 kts gusting to 20 testing out a new paddle - and actually really liked it.  So goes to show you do not need more than one board or one paddle to have a bit of planing fun.

But finding out if one board is faster than another via testing does have some merit.  A simple weighted side by side bridled tow test with separate strain gauges might work.

Probably the easiest "quick and dirty" way to compare the race effectiveness of two boards is to get two paddlers of similar ability to paddle a set distance many times at race pace and rotate use of the boards between trials. I would wager that the correlation between results from this procedure would correlate so highly with more sophisticated methods that most brands would be happy just use that - as they tend to do now. If you have a couple of elite racers on your sponsorship roster this is easy to do since at the very elite level the performance difference between the racers is often only a fraction of 1%.

Number one question (unless I missed it):  Why not name the boards?

First thanks for sharing your results, I feel you showed what I wish was not the case; that the more specifically designed flat water design was going to be a whole lot faster.
From my perspective, as a recreational paddler the approximately 3% difference in speed is rather minimal vs. the added versatility in mixed conditions (my last name is not Baxter), and certainly makes me question the difference between a $3800 race board and one costing $2600, much less something less expensive. I moved from a Amundson 14 TR-X to a lower rocker BlackBox UNO and based on my GPS results am about 5% faster, but a year later my paddling may also be a contributor. In retrospect, I suspect for many of us paddlers "operator error" is the best thing to work on.

Quote from: SUPflorida on June 22, 2016, 12:12:32 PM
I like the idea of towing a weighted board with a powerboat off the beam (away from any boat wake influence) with a strain gauge. This would allow you to venture beyond the millpond and get feedback on how the boards attributes work in a more realistic environment.

It may not be too telling in a small boat, which itself would be impacted by chop and wind...but a larger boat (80'+) could go through a couple feet of chop with impunity and provide a stable enough platform to give some data of value.

It would be interesting to see if this would provide a consistent "first level filter" to separate the sheep from the goats right up front before investing a lot of time in more elaborate testing.

Boat speed is highly variable. I'm converting a big servo I have to 360 drive and I'll use that along with an Arduino to manage the speed and a few hall effect sensors to make sure the servo isn't skipping. Should be easy to add a rope reel to that. String really, you don't need a lot of oomph to pull a weighted SUP through the water at 4 to 6 MPH

Quote from: baddog on June 22, 2016, 04:34:26 PM
Number one question (unless I missed it):  Why not name the boards?

Thanks for a good question. There were two reasons. The first, because I wanted the articles emphasis on establishing the scientific robustness of the tests themselves, not the boards. The boards performance differences are going to depend on the paddlers size, weight, ability and water/weather conditions. As a result, they are relative and I felt it would distract from what I wanted to show. The second was that I was not sponsored by the company of the boards so didn't feel it was appropriate to put useable intelligence for them in the public domain. However, if a company does want a battery of tests done, they are always welcome to contact me.

Quote from: PonoBill on June 22, 2016, 08:10:05 PM

Quote from: SUPflorida on June 22, 2016, 12:12:32 PM
I like the idea of towing a weighted board with a powerboat off the beam (away from any boat wake influence) with a strain gauge. This would allow you to venture beyond the millpond and get feedback on how the boards attributes work in a more realistic environment.

It may not be too telling in a small boat, which itself would be impacted by chop and wind...but a larger boat (80'+) could go through a couple feet of chop with impunity and provide a stable enough platform to give some data of value.

It would be interesting to see if this would provide a consistent "first level filter" to separate the sheep from the goats right up front before investing a lot of time in more elaborate testing.

Boat speed is highly variable. I'm converting a big servo I have to 360 drive and I'll use that along with an Arduino to manage the speed and a few hall effect sensors to make sure the servo isn't skipping. Should be easy to add a rope reel to that. String really, you don't need a lot of oomph to pull a weighted SUP through the water at 4 to 6 MPH

I think you'll need something with no stretch otherwise you'll get noise in the data. I assume that's why the original study used cable (which then had the strain gauges attached to it).

Quote from: Area 10 on June 22, 2016, 01:12:01 PM
Probably the easiest "quick and dirty" way to compare the race effectiveness of two boards is to get two paddlers of similar ability to paddle a set distance many times at race pace and rotate use of the boards between trials. I would wager that the correlation between results from this procedure would correlate so highly with more sophisticated methods that most brands would be happy just use that - as they tend to do now. If you have a couple of elite racers on your sponsorship roster this is easy to do since at the very elite level the performance difference between the racers is often only a fraction of 1%.

You may well be right. However, if the testing does not report margins of error and data repeatability, it should be regarded as limited in value (and thats the main fault with most peoples testing to date).

Plus, there is a long standing argument in research about the value of using 'experts' to test. Bear in mind that elites skill level and bodymass is likely to be more favourable (and not the actual market that the company is selling to) a different (i.e. 'normal) group of test mules might actually be of greater value in terms of the data's application and the boards marketability.

Quote from: Eagle on June 22, 2016, 11:23:11 AM
I think designers and brands use not only intuition - but direct input from their racers and race results.  Brands say they sometimes design 20+ prototypes before arriving at the end product on the shelf.  The multi-variables of a race or of a DW run seem to make it difficult to get scientific numbers that mean much in the real world.  But nothing ventured nothing gained - as some may say.

I think how rough or allwater boards are tested is a great debate in itself. I would definitely support the fact that the tests I've proposed are not exclusively suitable for them (or at least, only give you part of the information you need). My scenario that led up to this was that most races in the UK where I'm based are flatwater (rivers and lakes) and to then ask the question - 'could the popular all water models really be such a penalty in these kind of races ?'

Either way, races are changing in their strategy and participant numbers so it could be equally argued that it might be worth someone compromising on flatwater speed to use a board that gives them a better chance of surviving the early maelstrom of chop to ensure they get in the right draft train (rather than what was traditionally more of a solo effort time trial).

Quote from: Area 10 on June 22, 2016, 09:14:34 AM
It is an attractive option to remove the paddler from the tests altogether (e.g. by using a flow tank), in order to reduce error variance due to paddler differences. However this would be missing a critical point about SUP design and performance. This is that how fast a board is, at least in terms of average speed, is intimately related to how it copes with the forces acting upon it when someone paddles, in particular pitch and yaw. I've seen several raceboards that looked as if they should be fast when static in the water, but showed excessive pitching when the paddler put the power down, with a dramatic effect upon the efficiency of the board through the water. This is also why just letting the board glide while the paddlers stands motionless is also not likely to be a particularly good test of the real utility of a board in a race situation.

Hmmm - now who's got a flow tank in his garage???  ::) 8)

That geeza spends 6 days per week watching water dynamics  ;D

Quote from: ukgm on June 23, 2016, 12:21:30 AM

Quote from: Eagle on June 22, 2016, 11:23:11 AM
I think designers and brands use not only intuition - but direct input from their racers and race results.  Brands say they sometimes design 20+ prototypes before arriving at the end product on the shelf.  The multi-variables of a race or of a DW run seem to make it difficult to get scientific numbers that mean much in the real world.  But nothing ventured nothing gained - as some may say.

I think how rough or allwater boards are tested is a great debate in itself. I would definitely support the fact that the tests I've proposed are not exclusively suitable for them (or at least, only give you part of the information you need). My scenario that led up to this was that most races in the UK where I'm based are flatwater (rivers and lakes) and to then ask the question - 'could the popular all water models really be such a penalty in these kind of races ?'

Either way, races are changing in their strategy and participant numbers so it could be equally argued that it might be worth someone compromising on flatwater speed to use a board that gives them a better chance of surviving the early maelstrom of chop to ensure they get in the right draft train (rather than what was traditionally more of a solo effort time trial).

It's not only that, it's also that hybrid boards typically draft better than cutting bow ones, and that they are usually better to buoy turn, and are less technical and tiring to paddle (for a given width). These factors are why several top riders have recently used hybrid boards in what are ostensibly flat water races (eg. JL Sidewinder, SB All Star, and Mistral Equinox) in Europe this season. Plus, some paddlers using flat water specific narrow boards have come to regret it (eg. Jake Jenson).

Anyone who has owned a cutting now and a hybrid board will tell you that pushing a big blunt nose in flat water is highly disadvantageous as typical average race speeds. But we don't generally race in straight lines, in lanes, in pure flat water, and the further away you get from those conditions the less suitable a typical cutting bow design is.

(Of course, IMO it's not just the bow. It's what having a hybrid nose allows you to do elsewhere with the outline etc. But the biggest factor for a given rocker line and width is how blunt the nose is. I think.)

Quote from: Area 10 on June 23, 2016, 04:08:55 AM

Quote from: ukgm on June 23, 2016, 12:21:30 AM

Quote from: Eagle on June 22, 2016, 11:23:11 AM
I think designers and brands use not only intuition - but direct input from their racers and race results.  Brands say they sometimes design 20+ prototypes before arriving at the end product on the shelf.  The multi-variables of a race or of a DW run seem to make it difficult to get scientific numbers that mean much in the real world.  But nothing ventured nothing gained - as some may say.

I think how rough or allwater boards are tested is a great debate in itself. I would definitely support the fact that the tests I've proposed are not exclusively suitable for them (or at least, only give you part of the information you need). My scenario that led up to this was that most races in the UK where I'm based are flatwater (rivers and lakes) and to then ask the question - 'could the popular all water models really be such a penalty in these kind of races ?'

Either way, races are changing in their strategy and participant numbers so it could be equally argued that it might be worth someone compromising on flatwater speed to use a board that gives them a better chance of surviving the early maelstrom of chop to ensure they get in the right draft train (rather than what was traditionally more of a solo effort time trial).

It's not only that, it's also that hybrid boards typically draft better than cutting bow ones, and that they are usually better to buoy turn, and are less technical and tiring to paddle (for a given width). These factors are why several top riders have recently used hybrid boards in what are ostensibly flat water races (eg. JL Sidewinder, SB All Star, and Mistral Equinox) in Europe this season. Plus, some paddlers using flat water specific narrow boards have come to regret it (eg. Jake Jenson).

Anyone who has owned a cutting now and a hybrid board will tell you that pushing a big blunt nose in flat water is highly disadvantageous as typical average race speeds. But we don't generally race in straight lines, in lanes, in pure flat water, and the further away you get from those conditions the less suitable a typical cutting bow design is.

(Of course, IMO it's not just the bow. It's what having a hybrid nose allows you to do elsewhere with the outline etc. But the biggest factor for a given rocker line and width is how blunt the nose is. I think.)

Interesting thoughts. I wonder if the best strategy for people might be to accept use of an allwater board for the reasons you've stated and then go for the narrowest width the likely extra stability that kind of board affords (rather than just going for a likely slightly wider flatwater board per se' that they can manage).

Well, I think that is basically what is already happening. Partly this reflects the conditions and distance of most races. Many of the major international races are held in mixed conditions, and virtually all are middle-distance. So the designs are tending towards meeting that need. No doubt if most races were ultra-endurance, or sprints, or held in rowing lakes or well offshore, then the boards we use would look very different. But we seem to have largely settled on a kind of all-round compromise for many races. Even technical beach races in and out of the surf (eg. PPG) tend to have longer flat(ish) water sections in them. If the were just pure in-and-outs then the boards would look different.

For those of us who don't race seriously, the hybrid boards offer, perhaps, a pleasanter paddling experience since you can go narrower and they are technically easier to paddle, and mostly cope better with tricky conditions. It's funny that this "paddling experience" aspect is not discussed more. I guess it's because we can't put a number to it - yet. There's a scientific challenge for you!

I've got a flow tank, but it's four feet long.

Quite interesting.
board performance is very complex, even in flat water. i see 3 points:
1/ Wetted surface: theoretically lowest wetted surface would provide less underwater friction resistance, this is the case in displacement conditions, but not valid due to stability reasons, and because a paddler's speed is just something between displacement and planing conditions. however it should be taken into account, especially for UL lengths.
2/ Wave resistance: on a 12'6'' or 14' speed given by good level paddlers is something between hull speed on displacement limit and planing condition, with to speeds being claerly semi- planing conditions.
3/ periodical"up and down" weight changes: at each paddle stroke, weight of paddlers goes down ( lightening) and increases again, simultaneously with a shift of genter of gravity,, allowing board to "Jump" over the "Froude barrier" this effect is the most difficult to quantify. some brand designers study this effect and by adding concaves ( transversee and longitudinal including rear concave/channel) and optimizing hull flex, take substancial advantage from it.
This effect depend a lot on paddler's technique ( ie "Connor's style") and power- cadence given.  It allows planing hulls to perform in sprint conditions .
It is much less important on a long stroke/ spit stance technique such as "Terrel style" which may take better advantage to paddle a canoe-shaped hull... stability permitting ! but works better especially in endurance conditions, where a more classic hull keeps advantage. It is of course less important and profitable for heavy paddlers, beginners or medium level paddlers.  However it exists, and for that reason 2 paddlers of same weigh are not equal if teir technique is different, whatever is their real performance.

there are some other minor factors of influence, but for that reasons a board hull performance CANNOT be tested in a towing tank or such device. this is experience based, backed by computer design and art/sience of naval architect, in cooperation with paddlers.
This is another reason why some modern racing boards fit for champions will not be the best for medium level paddlers, and why "sprint" models are not adapted for distance paddling.
such test may work good for one paddler, but not for all.

Quote from: Area 10 on June 23, 2016, 06:18:45 AM
Well, I think that is basically what is already happening. Partly this reflects the conditions and distance of most races. Many of the major international races are held in mixed conditions, and virtually all are middle-distance. So the designs are tending towards meeting that need. No doubt if most races were ultra-endurance, or sprints, or held in rowing lakes or well offshore, then the boards we use would look very different. But we seem to have largely settled on a kind of all-round compromise for many races. Even technical beach races in and out of the surf (eg. PPG) tend to have longer flat(ish) water sections in them. If the were just pure in-and-outs then the boards would look different.

For those of us who don't race seriously, the hybrid boards offer, perhaps, a pleasanter paddling experience since you can go narrower and they are technically easier to paddle, and mostly cope better with tricky conditions. It's funny that this "paddling experience" aspect is not discussed more. I guess it's because we can't put a number to it - yet. There's a scientific challenge for you!

On that subject, I had the idea earlier about using the iphone as a deck mounted data logger to track board pitch and roll to see if 'paddling experience' could be correlated to pitch, yaw and roll metrics.

Quote from: Pierre on June 23, 2016, 07:13:45 AM
Quite interesting.
board performance is very complex, even in flat water. i see 3 points:
1/ Wetted surface: theoretically lowest wetted surface would provide less underwater friction resistance, this is the case in displacement conditions, but not valid due to stability reasons, and because a paddler's speed is just something between displacement and planing conditions. however it should be taken into account, especially for UL lengths.
2/ Wave resistance: on a 12'6'' or 14' speed given by good level paddlers is something between hull speed on displacement limit and planing condition, with to speeds being claerly semi- planing conditions.
3/ periodical"up and down" weight changes: at each paddle stroke, weight of paddlers goes down ( lightening) and increases again, simultaneously with a shift of genter of gravity,, allowing board to "Jump" over the "Froude barrier" this effect is the most difficult to quantify. some brand designers study this effect and by adding concaves ( transversee and longitudinal including rear concave/channel) and optimizing hull flex, take substancial advantage from it.
This effect depend a lot on paddler's technique ( ie "Connor's style") and power- cadence given.  It allows planing hulls to perform in sprint conditions .
It is much less important on a long stroke/ spit stance technique such as "Terrel style" which may take better advantage to paddle a canoe-shaped hull... stability permitting ! but works better especially in endurance conditions, where a more classic hull keeps advantage. It is of course less important and profitable for heavy paddlers, beginners or medium level paddlers.  However it exists, and for that reason 2 paddlers of same weigh are not equal if teir technique is different, whatever is their real performance.

there are some other minor factors of influence, but for that reasons a board hull performance CANNOT be tested in a towing tank or such device. this is experience based, backed by computer design and art/sience of naval architect, in cooperation with paddlers.
This is another reason why some modern racing boards fit for champions will not be the best for medium level paddlers, and why "sprint" models are not adapted for distance paddling.
such test may work good for one paddler, but not for all.

Thanks for this. Very interesting.

Any testing should be specific to the end user or the context for how the board should be used as much as possible. This is partly why things like test #2 I proposed considers a range of speeds (therefore a greater diversity of paddler ability) and why stroke rate is worth considering (in lieu of power) rather than relying on speed data alone. The slow down tests purely complement the others tests but I take your point about their lack of pitching, roll and yaw. The best board is ultimately one of compromise which might be why some companies (and Naish spring to mind) still haven't really jumped into producing specialised boards (even though people like Starboard have).


Either way, how would you suggest boards should be tested ?

(Note: I'm a little sceptical of manufacturers claiming they can promote or optimise dynamic aspects such as board flex - partly since this is incredibly difficult to simulate and robustly prove and requires some degree of scientific ability that most manufacturers either don't have or just haven't invested in the resources yet - especially the smaller ones. Team athletes offer the most qualitative feedback but don't generally have the ability or the time to provide robust quantitative feedback). I guess this leaves us with what you are saying (in that elite athletes and medium level  paddlers probably should not use the same boards) but either way, we should be looking at test methods beyond just the subjective when it comes to flatwater racing.)

Paddling is a long way from planing. Not some, not any, unless you're on a wave or in a swell. For any hull we'd be likely to paddle the planing speed is probably about 12 MPH. Never gonna get there except in a wave or swell, and waves let us cheat a bit by lifting the board and narrowing the width when we plant a rail in the face.

All SUP boards are displacement hulls. The difference between surfboards and race boards is bow penetration, rocker (waterline), rail design, maximum width point and length to width ratio. A good raceboard design makes the transition through the froude limit much flatter than something tubby, so it's much less of a limit and more of a point where the drag curve gets steeper. But they don't plane, even with Connor paddling. Dispense with that thought.

This is the curve for a variety of powerboat hulls. We don't generate even one horsepower, more like 1/2 for the most powerful paddlers. Elite rowers can generate 500 watts, but they have a much more powerful platform using the largest muscles efficiently. 500 watts is .6 hp. We're somewhere north of 250 pounds per shaft horsepower. Witha 200 pound guy at .5HP it's 400 pounds per horsepower. Where the curve kinks is where planing starts.  We are not even in the curve, 7MPH is the bottom edge of the graph. No we don't do it, and yes, this stuff applies.

(http://www.ponostyle.com/wp-content/uploads/2016/03/planing.png)

We don't even plane on a SUP with a sail. Do a little SUP sailing in some strong wind, and then just swtich to a modern sailboard. Okay, now you're planing and stable doing it. That wallowing you feel when you push the SUP hard in big wind is the board trying to climb the bow wave, and not making it. It's not planing, but it's lots of fun.  And we don't usually plane downwinding. We catch the wave and add it's energy, but we get some acceleration, and then generally settle and lose the wave. If you get deep to the bottom of a waist-high swell and turn across the face you might reach planing speed, but not often. It's why dropping into the big bombs on a Maliko run is so exhilerating, and control is so difficult. We probably ARE planing, and there's no step in the board for it to settle on, so it hunts, and wobbles, and scares the shit out of us.

When we launch from one wave on a DW and fly to the wave ahead without paddling - we are planing.  The board becomes very unstable and squirrelly like on marbles and takes off on you.  If you do not move back - you will fall off the back of the board.

So basically we just balance and wait until the board comes off plane and slows.  It then goes back to displacement mode.  We do not brace as this slows the speed and takes you off plane faster.

Once the board slows we start paddling hard to catch the wave ahead - and repeat.  We do this the whole run and are always catching up to the waves ahead.  So whether this is planing or semi-planing - the board is not in displacement mode.  More than half the board is out of the water.

The waves we plane on are much smaller but steeper and very short period - so the board becomes air-borne much easier.  This reduced friction allows planing to happen.  Now if I added 50 or 30 or even 10 lbs to me or the board - I probably could not plane.  Or would plane a lot less.

The speed difference between myself and my wife on a DW is so great - I have to stop multiple times for her to catch up.  She is in glide mode - at displacement speeds - and has never planed.  The strength to weight ratio is just not there for her.

To Ponobill, you are right about planing but not about displacement hulls, we cannot really plane on flat water, but planing is not just passing above"froude  barrier" or hull speed which is - in knots- 2.45xsqrt(length)... which corresponds to about 5.1 knots on a 14 footer ( L= 4.27 m) and is the wavelength of generated wake.... good level paddlers can reach that speed easily ang get above it on some boards... this is far from planing condition which needs a flat-rocketed tail and is generally about double of hull speed. between hull speed and planing there are semi-planing conditions which needs a hybrid shape - average width/depth ratio above 8, low rocker below gravity center, etc... a real planing hull will need more power to pass this condition and less in planing condition, a SUP is a semi-planing hull ( can be called a semi-displacement hull if U consider glass partly empty :P), hybrid between displacement hull and planing one may help, or because it is narrow enough ( rounded/ elliptical sections) or because the rocker and hull bottom is optimized to take advantage of stroke lightening, and THIS IS WHY SPRINTERS CAN REACH SPEED UP TO 1.4 x HULL SPEED! and with, as you say, only half a horse-power... Another way for displacement hull is to narrow hul to a fineness above 10 ( basically length/ width ratio) this is why a OC or kayak etc can break froude barrier.
a SUP  cannot really plane on flat water, even said-powered- because of its rocker  ( there is a kick tail, not same as on a windsurf board) but on a wave it can do, due to wave shape.
to UKgm, thanks for efforts, i am a little skeptical by habit, but who never tried never succeeded, so go for it.

On flat - paddlers like Connor and Kai look to be semi-planing - and only during the power phase when sprinting.  So it looks to be only momentary and intermittent.

No way the average Joe can ever hope to do that for any extended period of time.  Maybe for a second or two - but not much more.  The cardio and strength required is just too much for any mid-aged adult.

The unweighting via the bounce seems to help the board unstick.  I know that when I unweight off a bump - and time my pull with my 114 - I literally catapult forward.  And if the waves in front are small - which happens when you launch off the biggest bump of the set - you do scoot sometimes over two of them before slowing.  But you do have to gun it to keep at a semi-planing speed.

Some of us in our group of DW paddlers try to plane all the time on our 14s.  Since we like that little thrill.  As noted though - on the 17.4 it is a lot harder because of the extra weight of the board - and the huge amount of extra wetted surface area.  Mostly I just glide and connect on that - as it is too exhausting to get that board to unstick in the lower wind speeds consistently.

Quote from: Pierre on June 23, 2016, 01:38:46 PM
To Ponobill, you are right about planing but not about displacement hulls, we cannot really plane on flat water, but planing is not just passing above"froude  barrier" or hull speed which is - in knots- 2.45xsqrt(length)... which corresponds to about 5.1 knots on a 14 footer ( L= 4.27 m) and is the wavelength of generated wake.... good level paddlers can reach that speed easily ang get above it on some boards... this is far from planing condition which needs a flat-rocketed tail and is generally about double of hull speed. between hull speed and planing there are semi-planing conditions which needs a hybrid shape - average width/depth ratio above 8, low rocker below gravity center, etc... a real planing hull will need more power to pass this condition and less in planing condition, a SUP is a semi-planing hull ( can be called a semi-displacement hull if U consider glass partly empty :P), hybrid between displacement hull and planing one may help, or because it is narrow enough ( rounded/ elliptical sections) or because the rocker and hull bottom is optimized to take advantage of stroke lightening, and THIS IS WHY SPRINTERS CAN REACH SPEED UP TO 1.4 x HULL SPEED! and with, as you say, only half a horse-power... Another way for displacement hull is to narrow hul to a fineness above 10 ( basically length/ width ratio) this is why a OC or kayak etc can break froude barrier.
a SUP  cannot really plane on flat water, even said-powered- because of its rocker  ( there is a kick tail, not same as on a windsurf board) but on a wave it can do, due to wave shape.
to UKgm, thanks for efforts, i am a little skeptical by habit, but who never tried never succeeded, so go for it.

I never said planing was passing the Foude "barrier". It's not. Planing is simply the point where lift becomes the dominant force, where previously buoyancy was the dominant force holding the hull above water. You are reiterating things I've said here time and again regarding the froude barrier, which isn't a barrier at all, just a point where for some hull shapes the drag curve becomes very steep and for some it doesn't. There isn't any such thing as semi-planing other than a marketing phrase--its like saying semi-pregnant. Either list if dominant or it's not. Pro paddlers in a sprint don't get anywhere near planing speed, which is always a sharp and sudden departure, just as with hydrofoils lifting a hull clear of the water. At less than planing speed you are still pushing up bow waves and climbing them, above it you aren't.

Stroke lightening? Really? Good paddlers are doing their best to put all the force into accelerating the board and you think they've got something left to lift it out of the water? The bob the board inevitabley because they shift weight to the paddle, and there's an unavoidable upward vector force, but lightening to a plane. Nope. Don't just make shit up, read a bit. Or at least think.

Eagle--No. Just plain no.

Here's the fastest guys in the world sprinting at Lost Mills. None of them are doing anything like planing.
https://vimeo.com/67633595

And here's Jeremy Riggs and some of the worlds best non-pro downwinders on a decent sized Maliko.
https://vimeo.com/136187838
Look like planing to you? 1/2 to 3/4 of the board in the water, tail and rails in full contact.  If anyone could plane it's Jeremy. He might have planed once in this video. Having the nose come up a bit is not planing. Gliding isn't planing--it's where you match your board speed closely enough to the swell speed that energy can be effectively transferred.

"Semi-displacement, or semi-planing - the hull form is capable of developing a moderate amount of dynamic lift, however, most of the vessel's weight is still supported through buoyancy"

"Sail boats that plane must also sail efficiently in displacement mode in light winds."

As noted the 17.4 has a difficult time planing.  Those shots of JR are gliding.  We do that all the time on the 17.4 and 16 in our small waves.

The 14 Bullets and M-14 and other boards plane and semi-plane.  If still unconvinced - come on up in July when the wind is up and we can show you.

Connor looks to be semi-planing in his sprint as he is exceeding the max displacement speed based on the length of the board.

One of our local guys beat JR in the M2O - and as a sponsored rider he semi-planes his board easily.  Compared to Connor and Kai though - it seems the older guys are quite a bit slower with lower strength to weight ratios based on finishing times.

https://en.m.wikipedia.org/wiki/Hull_(watercraft)

Here are some comments about planing boards and sub-planing -

"Whereas the planing hull - the goal is to have the water go underneath the board and create lift.  So a planing hull will be faster to get on a plane and be faster once its released from the water and kind of gliding over the surface.  Which that kind of speed is only achievable if you have bumps that push you to get you up to that planing speed."

"sub-planing speeds"

https://youtu.be/Pe3UM0XNchY

Sorry, can't help you with any of that. These terms are specific, they don't get redefined because someone wants to sell a board. Those boards are not planing. Anyone who has windsurfed, sailed a planing hull boat, or driven a planing hull powerboat has a strong notion of exactly what planing is. It's not when you're pushing along with 3/4 of the board in the water and the tail buried with water flowing over it. When the board reaches planing speed, it lifts and the tail releases, Water moves under it in a V shape, being tossed to either side. There's no longer contact with a bow wave, the board is being lifted and it's bouyancy no longer matters.

We don't do that except on very rare occasion. I doubt your downwinding conditions exceed mine, or that your experience in doing it is long or as varied as mine. But I'm not the last word in any of that, and what I've experienced doesn't matter any more than what you have. It's just basic hydrodynamics, and the well-travelled understanding and research behind it all says the same thing. You won't find anyone with even a basic understanding who says anything different.

I agree with Robert that rocker is what distigushes a good downwind board from a flatwater racing board, but planing has nothing to do with it. In fact it's exactly the opposite. Rocker enables the board to stay in contact with the swell more uniformly, and helps transfer energy. If you wanted to plane you'd need some sort of step, and rocker would be your enemy. The tail rocker of a SUP virtually guarantees that it won't plane. Look at any modern windsurfer and you'll see what a planing hull looks like--nothing like a SUP.

Some hulls can be driven with power and speed well above an expected planing speed and never achieve planing. For example, hobie cats, and for that matter most racing catamarans, never plane.

We have windsurfed - sailed a planing hulled boat - and driven a planing hull powerboat.  At planing speeds.

And have a clear understanding of planing vs max displacement speed.  Those boards in the vid look to be semi-planing.  But unless you have ever planed a DW board - it will be hard to imagine unless you see it or experience it first hand.

1     Displacement
2     Semi-displacement (semi-planing)
3     Planing

All are very well defined specific terms anyone can look up.  But it seems the issue of strength to weight may be the underlying sticking point as previously noted.  As without the required ratio - even semi-planing is not possible - let alone full planing.

Sounds like unless you see it for yourself - you will remain unconvinced.  So if you are up to it - come on up and check out semi-planing and planing up north.

Okay, I give, you're planing. Whatever,

Are you guys just arguing about what term to use for a particular experience in the water? We've had many discussions on this forum over the years where people use the same terms to mean different things.

When you are surfing a wave, ie. actually on the wave face and moving up and down doing cutbacks etc, is that planing? Because if it is, there are certainly times when we do that when we are downwinding where I DW. The experience is indistinguishable from surfing: you are on the tail with most of the board out of the water and are travelling faster than the bump you are on, and indeed can move from your bump right over the one in front and into another trough altogether. There is a sudden surge of speed and the sensation is of falling down the trough, with predicable consequences if you don't angle the board quickly.

There are also other downwind bump-riding experiences, such as where you are sitting high on the face of the trough, almost sitting atop it, and are getting carried along with the bump. You don't have to paddle to make progress but your speed is never any faster than the bump you are on. If two of you are on bumps one behind the other, you travel at the same speed - faster than either of you could paddle in flat water (unless maybe you are Connor in a sprint) but not making any ground on each other. When you are bump-riding this way it is not possible to move from your trough to the one in front.

I guess that in my mind I call the first experience "downwind surfing" and the second "bump-riding". But is the first what Eagle is calling "planing" and the second what PB is describing in Rigg's video as "gliding"?

In some very short period steep downwind conditions, and on some boards, nearly all forward progress is through "downwind surfing" - it's a constant stop-start process. In some more regular conditions and with different boards, forward progress can be mostly or virtually all through bump-riding.

As for planing in flat water, under one's own power, I've never had any experience that I can equate with surfing a wave, even for a nanosecond. But then I'm not Connor or Danny. Although what they are doing doesn't look to my untrained eye like a stone skipping on the surface of water, which is what I'd think planing in flat water would look like.

But as I say, I know about the proper hydrodynamic terms for these experiences. I'm not sure we even need them to adequately discuss aspects of our paddling and the designs of boards. We can invent our own terms (which in many ways already seems to be happening). Then there might be less confusion.

Oh, and by he way, since the UK has just voted in a referendum today to leave the European Union, our currency has predictably crashed. So now SUPs are going to be even more crazily expensive here than they ever were. I feel very sorry for the SUP retailers and distributors in this country because they aren't going to be selling many boards in 2017 at this rate. The knock-on effect for the euro and strengthening of the Chinese currency in consequence may also affect board prices more broadly across Europe. Some board brands may have to move their centre of operations out of the UK in order to remain in contact with the rest of Europe - although there are rumours of other countries maybe following suit (eg. Holland) in having an in-out referendum too, so no-one is taking any bets on what will happen to the European dream right now. It's a momentous political, social and economic change and is very likely to impact on the business of SUP for us locally. It didn't help at all that Obama came over here a few weeks ago and told us that we must not leave and threatened us that if we did the US would put us on the naughty step. The UK population sympathetic to leaving basically instantly raised two fingers metaphorically (or maybe one middle digit if they originally came from the US) and told him to go forth and multiply, renewed in their resolve to sever as many ties with their allies as they could.

Anyway, I digress... And the people who voted for the exit from the EU were probably those who couldn't afford a SUP before anyway.

Your examples of surfing a wave and gliding are what we would expect and define as well.

Planing is when your board unsticks and catapults forward due to the wave behind pushing you - and you time the push by planting and pulling yourself forward with max force.  Akin to what Connor talks about on a skateboard - at the force needed for Kai to get his board up and foiling.  It is a huge amount of pull.  And why we use our 114 blade.  Size matters - as with a small blade you just cannot generate enough pull in a few tap tap tap strokes.

The force needed is explosive - and a sudden friction reduction occurs as you drop down the wave.  To get on plane you need to get over the buoyancy hump.  It requires proper timing and unweighting.  You need to step back to get the nose up so you can use the lift to plane.  The board then skips over the water as I describe on marbles.  Control is lost momentarily as the board planes.  The Bullets V1 and V2 plane faster and easier than the M-14 - as the rocker on the M-14 is huge.

So kinda like doing a muscle up.  Some people can maybe do a few pull-ups where their eyes barely get over the bar.  Some cannot even do one.  Others can pull up to their chest easily for reps - but never can time and explode to achieve a muscle up.  The sticking point is similar in planing.  Whereas in a muscle up it is the chicken wing transition - on a board to plane it is unsticking and launching forward with lift.  I can do muscle ups for reps easily - my wife cannot do one pull-up.  That is the strength to weight difference - it is really quite substantial.

Any less of a launch results in semi-planing.  We semi-plane a lot as we jump to the waves ahead.  The waves behind never catch up to us.  We always move forward.  And we look for the biggest cresting swells ahead - and semi-plane up to them.  They may be 5 or 6 waves ahead to the left or right.  We chase them down - and use that big one to plane off.  Within a run of an hour or so - we will plane about 5 times in winds about 20 kts.  When winds jack up to 25+ we plane a lot.  At those times - winds in Squamish create smaller waves as they bomb down a mountain.  So the fetch is very short - but the wind is high.  The windsurfers and kiters and foilers love that.  Whitecaps and spindrift are everywhere.  On a board - that is planing nirvana.

Upon entering Squamish - water shallows and the waves build in size.  In this steep and deep environment planing becomes a lot more difficult as the deep wave troughs slow you.  So best to go into glide mode at the speed of the swells and glide upriver.

A10 - hope you guys come out of it ok.  But a huge change for sure.  We went through Quebec wanting to separate years ago - so have some idea of the how a country can divide - as well as unite.

I think I misunderstood Ponobill's explanation a bit,  but the topic is flat water test, hope we will see positive output.

A10--yes, it's semantics, but the title of the thread is Scientific Flatwater Board Testing 101, which presumes some rigor. People use terms loosely all the time, and I know that few people want a lecture from a geek that paddles don't cavitate and neither do fins. Boards don't plane until lift is greater than buoyancy, blah, blah. They're the wrong word to describe the phenomenon because it has a specific meaning. And I realize words get appropriated all the time--mathematicians and physicists use common words to label thing that are wildly different from what people assume they mean, like "color" for quarks, or they make up words, like heteroscedasticity.

But in this thread I'd assume we're supposed to be a bit scientific, and talking about SUP boards having a planing hull is just nonsense. If they ever do plane (lift greater than buoyancy) it's an accident. The mental visualization for "is it planing" is simple. Picture the board that's supposed to be planing. Replace it with a flat slab with zero buoyancy. See if you can imagine it being still above water at the speed it's traveling with the motor it's got. Surfboards don't plane going down the face of a wave. They are designed expressly not to. You don't see super wide, totally flat tails on surfboards. That's what a planing hull looks like. If you've ever tried to surf a sail-less windsurfer you know how much they suck at it. the wide flat tail won't catch a wave.  Big wave gun? Planing? Never. Skipping like a stone? Sure. Turning across the face of the wave is a grey area. Riding the rail, most of the board out of the water. Smells like planing, might be, probably isn't. If the rail isn't dug in along it's length you're a passenger. Bob Simmons used to rant about this. Not a new issue. So yeah. maybe a wide tail simmons shape with straight rails, light weight, minimal float, zero tail rocker--that might be planing when it's maxed out, but even Simmons thought not. He thought with that much rail and that much width that buoyancy was probably still dominant. You want to plane, get a Paipo board.

If you want to know if you're planing or not, point your gopro at the tail. If the water is curling up the rails it ain't planing, if it's flinging out, you are. Let's see the pics.

But I'm not going to educate anyone, and most people don't care about this stuff. If you care, read up on this a bit. It's been an important issue in naval architecture and later in board design for the last 50 years. Of all the boards I can picture planing, a 25" wide, pintail 14' downwind board with continuous tail rocker is the second least likely candidate. Right behind an inflatable.

PB - well I'm a jobbing scientist, so I get used to people using the wrong terminology all the time. You can either get irritated by it (which I spent the first 20 years of my career doing) and lecture the person, or you can ask instead what it is that they are trying to communicate to you. Often, there might not be a perfect term for what they are describing. And this might be the case here. If we don't use the term "planing" then what term do we use to describe what is happening when we are full-on surfing a bump at, say, 15 mph? Very probably there is a good term for it. But if you used it no-one would know what you are talking about.

A good recent example is the use of the term "Ventral fin" that Larry Allison invented to refer to a fin that is placed forward of the standing area. "Ventral" is an anatomical term that most commonly means underside. So all fins are ventral fins, otherwise they wouldn't be sticking in the water. It would have made more sense for him to call them "anterior fins" or somesuch. Of course, I pointed this out on this forum, and everyone agreed, but here we all are now a couple of years later talking about "ventral fins" nevertheless.  So I guess it doesn't matter much since we all understand what we mean, even if it would seem bonkers to many other people who use this term in other (original) contexts.

Anyway, I might use the term "planing" hull (vs. "displacement") because that's what everyone else uses, even if it never actually planes in a true scientific sense. But if you have suggestions for a better term then let's hear them and maybe the SUP world will start adopting them. As for the downwind experience, well, I'm happy distinguishing between "gliding" and "surfing" a bump, when the latter describes travelling faster than the bump you started out on, and the former when you are just travelling with the bump. And as for flat water, well personally I can't really see any reason to think about planing in that context, magical though it is what people like Connor manage to do with the board. I think of that more like unweighting the board through a combination of transferring weight to the paddle and a movement of doing a kind of "standing crunch". But I'm willing to be educated, and I love to learn new words.

I don't really have one, glide works best for me, but it's a fuzzy notion. To me Glide denotes the energy transfer between board and swell or board and flatwater. There might be a technical term for it, but I don't know it. In downwinders, if you're going the right speed and your hull is appropriately shaped, you can transfer a lot more energy over a longer period of time and gain/maintain more speed. In flatwater, glide is just the coastdown deceleration, and if you don't weigh much, and your hull is efficient for the speed you start with, you coast down more slowly.

Glide works best for you - but is a fuzzy notion - interesting. 

Maybe Robert and all other SUP retailers should call their non-displacement boards "glide" boards then.

It would seem that the yachting world also should replace the word "semi-displacement (and semi-planing) hulls" - used for ages - to "glide" hulls since these words are not true words - but only made up for marketing purposes.  Please!  ;D

{If we don't use the term "planing" then what term do we use to describe what is happening when we are full-on surfing a bump at, say, 15 mph?}  Gliding at 15 mph.  Yes I'm gliding at 15 mph then!   ;D

Gliding might be fuzzy, but planing is not. Planing is a specific term for a transition. From buoyancy to lift. Like rolling to flying. If you want to say you're partially flying if you run along flapping your arms, please do so.

I refer you once again to the title of this thread. I'm not trying to get Robert and everyone else to stop using the term, I don't really care. I'm simply making the point that we don't plane.

I understood your position on "planing" and the non-word "semi-planing" from the get go.  Straw man and red herrings aside.

"There might be a technical term for it, but I don't know it."

Again - this is the technical term you are looking for - pre-googled for you.  Please check out any of the links and you will find the term.  There is a word in fact that fits between displacement and planing.  It is an actual occurrence - and it is ok.  Our ULDB is a semi-displacement semi-planing hull.  And we have planed that boat during races at 18 kts GPS.  And 15 kts and 10 kts etc.  At the lower speeds we are semi-planing not gliding!

https://www.google.ca/search?sclient=tablet-gws&site=webhp&source=hp&q=semi+planing+hull&oq=semi+planing&gs_l=tablet-gws.1.0.0l2j0i22i30.2391.6618.0.8757.12.10.0.2.2.0.145.867.7j3.10.0....0...1c.1.64.tablet-gws..0.12.879...0i131j0i10._mpqccLslZY

But hey - as noted I am perfectly ok with "gliding" at 15 mph as well.  I love gliding along at 15 mph moving forward quickly from swell to swell.

Yeah - everybody at Jaws must be gliding at 30 mph.  Check.

If SUP boards and you do not plane - and you don't really care - why continue to post nonsense.  Seems like you are telling everyone the term planing is nonsense as it relates to SUP - as according to you - they do not plane nor semi-plane - but glide!  Only one term is available to you "glide".  Got it.

Back to regular programming please!   ;D

Quote from: PonoBill on June 24, 2016, 11:38:35 AM

If you want to know if you're planing or not, point your gopro at the tail. If the water is curling up the rails it ain't planing, if it's flinging out, you are. Let's see the pics.

How ironic.  The master of spin wants lab results.   

I don't care what anyone calls it, Jeremy is zooming pretty good.
 
(http://i275.photobucket.com/albums/jj308/risley47/jeremy.jpg) (http://s275.photobucket.com/user/risley47/media/jeremy.jpg.html)

I've been clean for ten years.

A friend of mine who's a boat designer said that an assumed industry standard of a power boat achieving a point of planing was when the bow wake and the stern wake align (or become one).  I could tell when my windsurf board got to a plane. It would touch rail to rail and be otherwise airborne. I don't even think my skim board was ever actually planing....unless I used it in the UK:)   

Quote from: Pierre on June 24, 2016, 08:02:23 AM
I think I misunderstood Ponobill's explanation a bit,  but the topic is flat water test, hope we will see positive output.

Yes, semantic arguments aside, I would like to get back to this. However, I would like to pick up on a comment someone inferred to in a passing comment earlier - in that flatwater specific boards might not be the best kind of board design for the nuances of mass start racing. That kind of thought would have bearing on any test strategy that was designed. What do people think about this ?

Quote from: Area 10 on June 24, 2016, 02:58:11 AM
Oh, and by he way, since the UK has just voted in a referendum today to leave the European Union, our currency has predictably crashed. So now SUPs are going to be even more crazily expensive here than they ever were. I feel very sorry for the SUP retailers and distributors in this country because they aren't going to be selling many boards in 2017 at this rate. The knock-on effect for the euro and strengthening of the Chinese currency in consequence may also affect board prices more broadly across Europe. Some board brands may have to move their centre of operations out of the UK in order to remain in contact with the rest of Europe - although there are rumours of other countries maybe following suit (eg. Holland) in having an in-out referendum too, so no-one is taking any bets on what will happen to the European dream right now. It's a momentous political, social and economic change and is very likely to impact on the business of SUP for us locally. It didn't help at all that Obama came over here a few weeks ago and told us that we must not leave and threatened us that if we did the US would put us on the naughty step. The UK population sympathetic to leaving basically instantly raised two fingers metaphorically (or maybe one middle digit if they originally came from the US) and told him to go forth and multiply, renewed in their resolve to sever as many ties with their allies as they could.

Anyway, I digress... And the people who voted for the exit from the EU were probably those who couldn't afford a SUP before anyway.

Biggest disaster EVER??

Yes... Just over half the UK population are 'thick s shit' and the just under half have some sort of thought process going on..

You should've had needed to take an IQ test before casting vote!

Im feel totally ashamed to be part of this backward thinking bunch of puppets :(

A Dark time indeed.

Here are some reasons why the Brexit referendum played out the way it did.

http://www.bbc.com/news/uk-politics-eu-referendum-36574526

http://www.cbc.ca/news/world/scotland-considers-second-referendum-vote-1.3650596

With the Brexit referendum - the BQ are once again making news.

http://www.cbc.ca/news/canada/montreal/brexit-quebec-sovereignty-1.3651265

https://en.m.wikipedia.org/wiki/Quebec_referendum,_1995

Quote from: Eagle on June 25, 2016, 01:19:58 PM
Here are some reasons why the Brexit referendum played out the way it did.

http://www.bbc.com/news/uk-politics-eu-referendum-36574526

http://www.cbc.ca/news/world/scotland-considers-second-referendum-vote-1.3650596

With the Brexit referendum - the BQ are once again making news.

http://www.cbc.ca/news/canada/montreal/brexit-quebec-sovereignty-1.3651265

https://en.m.wikipedia.org/wiki/Quebec_referendum,_1995

Anyway, let's get back to boards......

Pund crashed? So go and built boards in UK, exports will be cheap and affordable, and british commercial balance awesome, not as France... :P

Talking back about the topic, UKGM, do you think about comparing different board's lengths? UL vs 14' ?

Pund crashed? So go and built boards in UK, exports will be cheap and affordable, and british commercial balance awesome, not as France... :P

Quote from: PonoBill on June 24, 2016, 11:38:35 AM

If you want to know if you're planing or not, point your gopro at the tail. If the water is curling up the rails it ain't planing, if it's flinging out, you are. Let's see the pics.

But I'm not going to educate anyone, and most people don't care about this stuff. If you care, read up on this a bit. It's been an important issue in naval architecture and later in board design for the last 50 years. Of all the boards I can picture planing, a 25" wide, pintail 14' downwind board with continuous tail rocker is the second least likely candidate. Right behind an inflatable.

In this photo I'm on a 14' rockered pintail Bump Rider downwind board, going at less than 10 mph.  I'm not sure if planing is the scientifically correct term but I don't think it's displacement, the board is sliding over the surface of the water, not pushing through it, so what would you call this if it's not planing?

Quote from: Pierre on June 27, 2016, 06:05:38 AM
Talking back about the topic, UKGM, do you think about comparing different board's lengths? UL vs 14' ?

I'm personally very interested in UL boards but with the racing scene completely redundant in the UK, it wouldn't be the best use of time. I think fin choice and board choice has to be a higher priority for me.

Quote from: blueplanetsurf on June 27, 2016, 06:53:59 AM

Quote from: PonoBill on June 24, 2016, 11:38:35 AM

If you want to know if you're planing or not, point your gopro at the tail. If the water is curling up the rails it ain't planing, if it's flinging out, you are. Let's see the pics.

But I'm not going to educate anyone, and most people don't care about this stuff. If you care, read up on this a bit. It's been an important issue in naval architecture and later in board design for the last 50 years. Of all the boards I can picture planing, a 25" wide, pintail 14' downwind board with continuous tail rocker is the second least likely candidate. Right behind an inflatable.

In this photo I'm on a 14' rockered pintail Bump Rider downwind board, going at less than 10 mph.  I'm not sure if planing is the scientifically correct term but I don't think it's displacement, the board is sliding over the surface of the water, not pushing through it, so what would you call this if it's not planing?

I'd call it "Not Planing", and of course it's in displacement mode. See where the bow wave is, well in front of your feet about where the Blue Planet logo is? See where the stern wave is? Not planing. If you reshaped that board to have a nice big flat spot in the tail it might plane. If you have substantial tail rocker when the bow wave moves back the board becomes a teeter totter. Move it back a little and the tail gets buried.  Imagine the circumstance Talldude mentioned where the bow and stern wave meet with a rockered board. How much energy do you think will be transferred between the board and a bump when the contact area is a line? Have you ever been "planing" on your rockered board when it radically tips forward and back? I haven't. That's what it would do, and it would most likely tip back given the remaining little bit of force.

You need a planing surface to plane. Why does a Simmons board have no tail rocker and a big wide tail? It's not so fat guys with lousy balance can stand on them, it's so they can plane. That's why a short, wide board with that specific Simmons design is fast as blazes down the face of a wave. It planes. Build the same board with anything other than a tiny bit of rocker at the extreme end of the tail and it won't plane. "Regular" short, wide boards with continuous rocker are slugs by comparison. It's also why Simmons shapes are so bitchy about pitch stability--especially to the rear. There's very little secondary stability. You aren't gaining an exponential amount of bouyancy as you sink the tail, it's a flat line.

Look at windsurfing board from the 80's, look at a modern one. We had a hell of a time getting older windfurers to plane. Why? Because they didn't have a planing hull. Talk to any shaper that did both windsurfers and surfboards. Tell him that you think your 14' rockerd board is planing. If he doesn't laugh at you it wil be because he's nicer than me.

It's not speed. It's pounds per horsepower (125 being the magic number) and hull design. You can get a catamaran going 20kts and it won't plane. Never. There is such a thing as a planing catamaran. I remember them. Some outfit in Australia made them. Fun to play with, bitch to control.

Planing is a specifc thing. It's not having a hull that's transversely flattened but has rocker. Call it anything you like, but it still ain't gonna plane. We COULD have planing downwind boards. It's an interesting design choice. I think it might be tough to make it work other places, but in a big bump it could be fast as hell. I think some of the SUP that paddled Peahi this year had planing hulls. I didn't get to look at Kai's board, but it looked very different from the prone guns that follow the traditional big wave design of keeping as much of the rail and hull in contact with big, steep waves as possible.

Sorry UK, if I want to waste my breath a little more talking about this I'll start a new thread, but at least we've not talking about Brexit.

More on topic, I've ordered a stepper motor and controller to build a precision winch. My 360 servo idea didn't work--too wimpy, even with a big metal gear servo. I was going all nutty trying to figure out how to keep speed constant while the winch drum grows in diameter as you add windings when I realized I don't have to. The speed and power recorder will be on the board. Duh. I just need to keep the motor speed constant so there aren't any sudden pulses.

To summarize, a hull is submitted to 2 vertical forces: weight and its opposite. in static conditions, supporting force opposed to weight is BUOYANCY which is HYDROSTATIC LIFT, defined by Archimede's principle, When hull moves through water other forces occuring at some speed are HYDRODYNAMIC forces due to wave resistance and are lift at the bow and the stern wave, and negative lift at the hull's largest wetted section... those lift forces have a marginal effect as their sum is about zero.  so hull is still supported by hydrostatic lift... we are in displacement conditions.
when  a wide enough  hull speeds up above hull speed, its stern wave moves behind tail and bow wave moves below hull,   weight is supported partly by buoyancy and gradually, partly, by hydronamic lift... If hull is a pure planing hull and speed is enough, generally when stern wave is very far behind hull ( more than 2 or 3 hull's lengths), so to see stern wave a bit behind hull does not mean you are planing, you just start to experience some kind of semi-planing...
On planing condition  weight is supported almost totally by hydrodynamic lift. this occurs on hard chine V-shaped, flat, or concave,  flat rockered wide hulls, at speeds about double of "hull speed" ( depends on hull shape). A planing hull , when on planing condition, Does not need volume to stay on water ( such as wakeboards, water skis, Alaias, paipos, "sinker" windsurf boards...
planing speed depends also on water depth... in very shallow water ( as on a skimboard) planing is easier...
Some saling boats with flattened rounded section can nearly plane, if rocker is very flat and sail power is a lot... a windsurf board planes easier due to flat bottom, but performs less at displacement speeds. motor powerboats are often V-bottomed to avoid slamming and keep control in choppy water, even this delays planing. Hard chines help planing ability.
SUP boards ,if very low- rocker, and if paddled by swift and strong athletes, can reach some kind of semi-planing conditions, hlped by po-up effect due to loss of weight between stroke, excepted on DW with bumps ( or on flatwater with very very srong winds  ::)) but I do not believ hydrodynamic lift is more than half of hydrostatic lift...

Quote from: PonoBill on June 27, 2016, 08:55:04 AM

Quote from: blueplanetsurf on June 27, 2016, 06:53:59 AM

Quote from: PonoBill on June 24, 2016, 11:38:35 AM
If you want to know if you're planing or not, point your gopro at the tail. If the water is curling up the rails it ain't planing, if it's flinging out, you are. Let's see the pics.

In this photo I'm on a 14' rockered pintail Bump Rider downwind board, going at less than 10 mph.  I'm not sure if planing is the scientifically correct term but I don't think it's displacement, the board is sliding over the surface of the water, not pushing through it, so what would you call this if it's not planing?

I'd call it "Not Planing", and of course it's in displacement mode. See where the bow wave is, well in front of your feet about where the Blue Planet logo is? See where the stern wave is? Not planing.

Tell him that you think your 14' rockerd board is planing. If he doesn't laugh at you it wil be because he's nicer than me.

Planing is a specifc thing. It's not having a hull that's transversely flattened but has rocker. Call it anything you like, but it still ain't gonna plane.

https://www.google.ca/search?sclient=tablet-gws&site=webhp&source=hp&q=planing+hull&oq=planing+hull&gs_l=tablet-gws.3..0l3.2134.6006.0.6655.12.10.0.2.2.0.134.1058.2j8.10.0....0...1c.1.64.tablet-gws..0.12.1061...0i131j0i10.bOEYjzvt1ZM

Ok, so clearly there is a speed gap between the hull speed of a board, let's call it about 7 mph and planing speed which is supposedly above 12 mph. 
So if that in-between speed, above 8 mph but below 12 mph, that we are achieving during downwinders, where the board releases and drag is greatly reduced but the board is not fully planing, what do we call that? 
Sub-planing?  Really? 
I'll keep calling it planing because that's how it feels, even if it's not the scientifically correct term.

Quote from: blueplanetsurf on June 28, 2016, 01:54:09 AM
Ok, so clearly there is a speed gap between the hull speed of a board, let's call it about 7 mph and planing speed which is supposedly above 12 mph. 
So if that in-between speed, above 8 mph but below 12 mph, that we are achieving during downwinders, where the board releases and drag is greatly reduced but the board is not fully planing, what do we call that? 
Sub-planing?  Really? 
I'll keep calling it planing because that's how it feels, even if it's not the scientifically correct term.

As your board starts to lift and ride on top of the water, it is to some degree starting to plane. You can feel it. It happens in slick flatwater when you're really pushing it or on a bump. To give it a hard number like 12 mph or scientific definition is pointless outside of a laboratory. So yes, I'm with you Robert.

I know that feeling and coming from a windsurfing background I'd not call it planing..

I think the word I'd use is surging or releasing without planing..

I don't have a dog in this, ah, discussion but have been following it with great interest.

There is nothing new under the sun.

Check the archives right here:

www.standupzone.com/forum/index.php?topic=6605.0

Folks seemed a little less didactic with their opinions back then..

Quote from: blueplanetsurf on June 28, 2016, 01:54:09 AM
I'll keep calling it planing because that's how it feels, even if it's not the scientifically correct term.

+1

Also, it has become a term of art within the paddling community. For the last couple of years the pro's. Conor, Kai, etc. have used the term planing to describe board speeds above displacement speeds.   

I guess planing is like pornography, you know it when you see it. ;D

These are quotes from the topic linked by mrbig a couple of posts earlier titled -> Planing Hull vs Displacement Hull?

DJ posted this in 2010 -

"I'm not into displacement hulls unless it's just for rivers or lakes with no real runners... If it's runners that you're into I think planing hulls are the way to go for sure.

For me it's all about getting on the plane and surfing the bumps and not just surging along in the way displacement hulls like to cruise.. even if they are faster.

DJ"

And PB posted this -

"Planing hulls look like surfboards, displacement hulls look like canoes."

Quote from: Eagle on June 23, 2016, 09:03:35 PM
Here are some comments about planing boards and sub-planing -

"Whereas the planing hull - the goal is to have the water go underneath the board and create lift.  So a planing hull will be faster to get on a plane and be faster once its released from the water and kind of gliding over the surface.  Which that kind of speed is only achievable if you have bumps that push you to get you up to that planing speed."

"sub-planing speeds"

https://youtu.be/Pe3UM0XNchY

And oh Robert - about 3:00 in your vid you use the term "sub-planing speeds" - so that's why it was put in quotes way back when.

But my perspective should be quite clear.  I am perfectly ok to call it gliding at 15 mph.  Or planing.  Or semi-planing.  Or whatever.

It is fun and gives a bit of a thrill - and that's what really counts to me and my friends when we DW -> and have a beer after.  We all talk about DW from a planing perspective - but those that cannot plane - do love the gliding aspect as well.  That is what pushes us to drop fat and put on muscle -> to plane like we see the pros doing.  Even if it is only for a second or two.  Pretty much all the guys that paddle with us are very fit lads - and very good DW paddlers and racers.  Many considerably better than me.  I am probably about mid-pack.  So very average.

As an aside - my wife loves gliding and getting pushed along by the waves when we head up to Squamish.  So the way I look at it - as long as you enjoy what you are doing and you're not hurting anyone - just do it.  That seems to our mentality anyways.  We just use normal common words and descriptors is all.  Glide - plane - surf - semi-plane - whatever.   :)

a. It's not speed that determines planing, well it does, if you have a planing hull, but NO--there are plenty of craft that don't plane that go very fast.

b. Planing is a specific term. Use it as you like, but that doesn't change what it is.

c. If you can see the bow wave in front of, you ain't planing. Period. You aren't semi planing any more than you are semi alive if you have a hangover.

d. Semi-planing is a bullshit marketing term, to describe hulls that can both plane but have displacement characteristics when they aren't. They don't beat your brains to jello at lower speeds. Yes, Larry, Marketing bullshit is what I did to make money, I'm comfortably retired from marketing bullshit. that's one reason why I know what it is.

e. When you climb the bow wave with a rockered hull, more and more of the nose sticks out of the water. That means you have a shorter waterline, which makes the speed that the froude "limit" starts getting exponential come sooner. One more reason rockered hulls don't plane. Every inch the waterline shortens is more energy required.

f. Planing happens when the hull rolls over the bow wave, or in shorthand terms, when the bow wave meets the stern wave. If you're looking at your bow wave in front of you, you are decisively NOT planing.

Most importantly, it's not me saying this. You don't have to listen to me or believe a thing I say.  Google is a click away. What you believe is meaningless. what you know is useful. You might believe in little green men, or that an invisible dead guy is running your life. Nice for you, I don't care. Look it up. read. If you find something that isn't marketing bullshit, that says I'm talking out of my ass, then I'm all ears. But SUPs aren't a bit different than any of the hulls developed over the last hundred years. You don't have to make this shit up. It's all available.

Start by reading about what Sims was up to, just trying to make a shortboard plane. But don't stop there. There's a hundred years worth of literature about this--it all says the same thing. It's just physics.

Back when the zone started there were people who wanted to punch me in the nose because I said board length was the critical determinant for the speed of a board except for special cases. Byron Yap and I got into a serious pissing match about that. The consensus was that it was all about the paddler. Here we are, talking about froude limits. Maybe people actually understand that now. Probably not. The best way to talk about any of this is with math.

And Eagle, if you're going to quote me from 2010, it would be cool to include all relevant parts of the quote, even if it doesn't help prove your point:
"without looking at rocker. Planing hulls look like surfboards, displacement hulls look like canoes."

Where is the bow wave in this pic?  It seems you are the only one who says no SUP planes or whatever.  I told you - gliding at 15 mph is perfectly ok by me.  Others now are talking about planing and whatever - leave me out of your nonsense argument.  I told you I completely understand your position.  You can leave me out of your pissing match.  SUPs do not plane.  Got that.   ;)

And the link -> anybody can go back to check for context etc - that's why it was referenced.   :)

There isn't any, he's probably planing. Glad to leave you out, in fact I have been. I see no reason to contiue a conversation with you. I was responding to Robert. Included you ONLY because you quoted me.

Merci beaucoup.   ;)

We have gotten way off topic here, sorry.  Bill, you are probably right but I do enjoy arguing with you so I will keep going.
So what exactly is the scientific definition of planing?  I don't care about pounds per horsepower because we don't use motors.
I agree that semi-planing is a bullshit term but there is some kind of sliding over the water surface going on at "sub-planing" speeds.  Check out this photo, the big bow wave is coming off by the nose yet the board is still sliding over the water with dynamic lift, clearly not for much longer but to me he is still planing, right?

Planing is when the bow wave joins the stern wave. Doesn't matter where. For us on long DW boards that'll be further back, so effectively will be out of sight for the paddler. For the skim boarder it's happening up front - but he is planing. You can clearly see there aren't 2 separate waves. That thing doesn't have enough volume to float him if he wasn't planing anyway.

It's funny. When I was 14 or so, during a group conversation which involved planing, I asked what planing was to my sailing coach. His answer was short and simple: "Planing is when the bow wave joins the stern wave". At the time I remember thinking that he hadn't really answered my question, or certainly hadn't helped me visualise what they were talking about. I eventually figured out what was meant by planing from the feeling, which is pretty distinctive. Over time my coaches answer stay with me and I learned to recognise it.

I do think it is a distinctive feeling. If it feels like planing it is. Whatever the craft. Motorboat, yacht, dinghy, windsurfer, SUP. You really feel it driving a wakeboard boat, like I was the other day, at slow speeds. It's almost like a pivot point. And often the optimal wake is right around that pivot point. Tricky to drive if it isn't one of those new boats optimised for that. Sinkers like short surfboards, skimboards, wakeboard and kite boards (the little ones) pretty much have only planing mode else they're underwater.

https://en.wikipedia.org/wiki/Planing_(boat)

I found this explanation on Wikipedia:

How planing works:
When it is at rest, a vessel's weight is borne entirely by the buoyant force. At low speeds every hull acts as a displacement hull, meaning that the buoyant force is mainly responsible for supporting the craft. As speed increases, hydrodynamic lift increases as well. In contrast, the buoyant force decreases as the hull lifts out of the water, decreasing the displaced volume. At some speed, lift becomes the predominant upward force on the hull and the vessel is planing.

^ and we can feel that.

Quote from: blueplanetsurf on June 28, 2016, 11:20:22 PM
https://en.wikipedia.org/wiki/Planing_(boat)

I found this explanation on Wikipedia:

How planing works:
When it is at rest, a vessel's weight is borne entirely by the buoyant force. At low speeds every hull acts as a displacement hull, meaning that the buoyant force is mainly responsible for supporting the craft. As speed increases, hydrodynamic lift increases as well. In contrast, the buoyant force decreases as the hull lifts out of the water, decreasing the displaced volume. At some speed, lift becomes the predominant upward force on the hull and the vessel is planing.

Everyone knows wikipedia is gospel ;-).

Can we move on and maybe even get back on thread ? (start a new one for the planing argument)

Yes, you can feel it.  To me, Travis surfing on the big wave is clearly planing, no doubt about that.
But going back to this photo of riding a bump at lower speeds (less than 12 mph), I would still call this planing.

You can see the rails of the board are not touching the water, the water is spraying off the tucked under rail and not wrapping around the rails.   The paddler's weight is therefore clearly supported predominantly by the lift created by water moving under the bottom surface of the board, not by the buoyant force of the rails.  If you look carefully you can see that the rails are not really touching the water, so the lift created by the board's volume is minimal in comparison to the hydrostatic lift.

So to me there is are only these two states:
1) Displacement where the predominant lift comes from the displaced volume
2) Planing, where the predominant lift comes from hydrodynamic lift. 

The transition between these two states is very noticeable, either fast acceleration and a sensation of lifting and sliding on top of the water or deceleration and a feeling of the hull dropping back down into the water.

[/quote]

Everyone knows wikipedia is gospel ;-).

Can we move on and maybe even get back on thread ? (start a new one for the planing argument)
[/quote]

Ok, sorry, I'm done

Back to Scientific Flatwater Board Testing 101...

Is it true red boards are faster?

Only in pantone 805 c 2x!!

My red (Pantone 186C) 14x28 Fanatic was faster on flat water than my yellow and black 14x26 Javelin.  ;D

Quote from: Bean on June 29, 2016, 06:28:35 AM
My red (Pantone 186C) 14x28 Fanatic was faster on flat water than my yellow and black 14x26 Javelin.  ;D

What year models ?

Quote from: LaPerouseBay on June 24, 2016, 04:49:10 PM

How ironic.  The master of spin wants lab results.   

Quote from: PonoBill on June 24, 2016, 04:56:11 PM
I've been clean for ten years.

Perfect analogy, once an addict, always an addict.

Quote from: PonoBill on June 27, 2016, 08:55:04 AM
/
Look at windsurfing board from the 80's, look at a modern one. We had a hell of a time getting older windfurers to plane. Why? Because they didn't have a planing hull. Talk to any shaper that did both windsurfers and surfboards. Tell him that you think your 14' rockerd board is planing. If he doesn't laugh at you it wil be because he's nicer than me.
/

http://www.standupzone.com/forum/index.php/topic,10934.msg96137.html#msg96137

Hey, this spin stuff is kinda fun! 

Quote from: ukgm on June 29, 2016, 06:59:21 AM

Quote from: Bean on June 29, 2016, 06:28:35 AM
My red (Pantone 186C) 14x28 Fanatic was faster on flat water than my yellow and black 14x26 Javelin.  ;D

What year models ?

2011 Fly Race and 2015 Javelin LE.  But, the Jav is a better all-rounder for sure.

Bean, those are the paint codes for my JP 2015 race. Fast, but really tippy. Changed in 2016 again and in 2017..

186C is really the code for the more recent Falcon, so I was just winging it. ;D

Quote from: LaPerouseBay on June 29, 2016, 10:22:28 AM

Perfect analogy, once an addict, always an addict.

Yeah, well, maybe.

But ask Bill if he thinks his Maliko 14's actually plane.

Quote from: ukgm on June 28, 2016, 11:49:53 PM

Quote from: blueplanetsurf on June 28, 2016, 11:20:22 PM
https://en.wikipedia.org/wiki/Planing_(boat)

I found this explanation on Wikipedia:

How planing works:
When it is at rest, a vessel's weight is borne entirely by the buoyant force. At low speeds every hull acts as a displacement hull, meaning that the buoyant force is mainly responsible for supporting the craft. As speed increases, hydrodynamic lift increases as well. In contrast, the buoyant force decreases as the hull lifts out of the water, decreasing the displaced volume. At some speed, lift becomes the predominant upward force on the hull and the vessel is planing.

Everyone knows wikipedia is gospel ;-).

Can we move on and maybe even get back on thread ? (start a new one for the planing argument)

Larry has now put his own data up here: http://www.larrycain.ca/blog/blog/

I'm going to add some stats to his FB page regarding it later in the day.

Quote from: ukgm on June 23, 2016, 07:45:06 AM

(Note: I'm a little sceptical of manufacturers claiming they can promote or optimise dynamic aspects such as board flex - partly since this is incredibly difficult to simulate and robustly prove and requires some degree of scientific ability that most manufacturers either don't have or just haven't invested in the resources yet - especially the smaller ones. Team athletes offer the most qualitative feedback but don't generally have the ability or the time to provide robust quantitative feedback). I guess this leaves us with what you are saying (in that elite athletes and medium level  paddlers probably should not use the same boards) but either way, we should be looking at test methods beyond just the subjective when it comes to flatwater racing.)

this is experience- based, how can we explain an inflatable works so good in some conditions, with its negative middle rocker in still situation?  something like a surf mattress surfing?...  flex stores energy and gives it back,  the most difficult is to direct this back energy the right way....
I have some plywood hollow SUP boards with minimal structure ( longitudinal only), keel is quite still but bottom sheet a bit flexible, and despite their weight, they perform unreally well.... :)

Quote from: Pierre on June 30, 2016, 03:46:44 AM

Quote from: ukgm on June 23, 2016, 07:45:06 AM

(Note: I'm a little sceptical of manufacturers claiming they can promote or optimise dynamic aspects such as board flex - partly since this is incredibly difficult to simulate and robustly prove and requires some degree of scientific ability that most manufacturers either don't have or just haven't invested in the resources yet - especially the smaller ones. Team athletes offer the most qualitative feedback but don't generally have the ability or the time to provide robust quantitative feedback). I guess this leaves us with what you are saying (in that elite athletes and medium level  paddlers probably should not use the same boards) but either way, we should be looking at test methods beyond just the subjective when it comes to flatwater racing.)

this is experience- based, how can we explain an inflatable works so good in some conditions, with its negative middle rocker in still situation?  something like a surf mattress surfing?...  flex stores energy and gives it back,  the most difficult is to direct this back energy the right way....
I have some plywood hollow SUP boards with minimal structure ( longitudinal only), keel is quite still but bottom sheet a bit flexible, and despite their weight, they perform unreally well.... :)

If you're going to promote board flex as a performance enhancing effect (as Starboard do), you can't just use anecdotal experience for the reasons I've given. The magnitude, direction and timing of the energy return is critical (I've been involved with this problem with respect to prosthetic limbs used for running). As always, some boards might do well 'in spite of flex' not 'because of'. We need data for that.

Wow, Larry's article is very interesting. I like the notion of stroke effectiveness, it encapsulates several elements of paddling that I've been thinking about lately which motivated me to buy both a vivoactive watch and a Speed Coach as well as dusting off all the bits for the Paddle Pod I built years ago. Absent direct measurement of power, a result-based number like distance per stroke time velocity gives a good measure of power applied in an efficient manner. The problem I see with direct power measurement is that it doesn't translate into performance without a measure of efficiency. However we go about deriving efficiency, the way to get to a useful power figure is measured power times efficiency. Stroke performance does that directly.

I think I'm barking up the wrong tree thinking about measuring hull performance with a winch dragging weighted boards across Nichols Boat Basin. I'd be measuring a very static characteristic that must change quite a bit in a dynamic environment. The first thing that came to mind about Larry's testing is that "well, that calm flat water is never encountered in a race". I should hold the same criteria to my own ideas. No one is racing paddleboards by dragging them across flatwater. My proposed method is probably an order of magnitude less relevant than Larry's test. I need to think of something else to do with my new high-torque stepper motor and arduino shield.

I haven't tested the accuracy of the speed coach, but from the specifications, it seems capable of either directly measuring or deriving all the factors in Larry's test. Speed is probably pretty good, and that's easy to calibrate. Record instantaneous speed, try to hold it constant for a measured distance. I can check stroke rate accuracy with video, as well as stroke distance, which is certainly a calculated value. Of course everything the Speed Coach displays is calculated from GPS data, so the accuracy of that data determines accuracy of everything else. Decoupling speed from GPS data with a dragged impeller might be worthwhile if any inaccuracies show up.

Anyway, very cool article. Food for thought for days.  I think a combination of UKGM's rigor and Larry's aim for results that correllate to actual performance would yield some excellent information. I'd like to read your full paper if you're comfortable with that, UK.

Quote from: PonoBill on June 30, 2016, 06:39:31 AM
Wow, Larry's article is very interesting. I like the notion of stroke effectiveness, it encapsulates several elements of paddling that I've been thinking about lately which motivated me to buy both a vivoactive watch and a Speed Coach as well as dusting off all the bits for the Paddle Pod I built years ago. Absent direct measurement of power, a result-based number like distance per stroke time velocity gives a good measure of power applied in an efficient manner. The problem I see with direct power measurement is that it doesn't translate into performance without a measure of efficiency. However we go about deriving efficiency, the way to get to a useful power figure is measured power times efficiency. Stroke performance does that directly.

I think I'm barking up the wrong tree thinking about measuring hull performance with a winch dragging weighted boards across Nichols Boat Basin. I'd be measuring a very static characteristic that must change quite a bit in a dynamic environment. The first thing that came to mind about Larry's testing is that "well, that calm flat water is never encountered in a race". I should hold the same criteria to my own ideas. No one is racing paddleboards by dragging them across flatwater. My proposed method is probably an order of magnitude less relevant than Larry's test. I need to think of something else to do with my new high-torque stepper motor and arduino shield.

I haven't tested the accuracy of the speed coach, but from the specifications, it seems capable of either directly measuring or deriving all the factors in Larry's test. Speed is probably pretty good, and that's easy to calibrate. Record instantaneous speed, try to hold it constant for a measured distance. I can check stroke rate accuracy with video, as well as stroke distance, which is certainly a calculated value. Of course everything the Speed Coach displays is calculated from GPS data, so the accuracy of that data determines accuracy of everything else. Decoupling speed from GPS data with a dragged impeller might be worthwhile if any inaccuracies show up.

Anyway, very cool article. Food for thought for days.  I think a combination of UKGM's rigor and Larry's aim for results that correllate to actual performance would yield some excellent information. I'd like to read your full paper if you're comfortable with that, UK.

I'm still doing some more data collection but I fully intend to put it in the public domain on an open access journal when its done. This might be a while yet though. In answer to your question though, the Speedcoach should do just fine. I also did my slowdown test which also loses some specificity of paddling like your idea of a drag test  but its important to try to separate board performance from paddling performance and the two would complement (but not replace) each other.

Well, I've got all the parts, might as well build it and try it.

I was reading this test and have to say it's at best semi scientific. The biggest variable, the paddler is not taken out of this test. Not only do you have the conditions as a variable but also the paddler. You can do as many test runs as you wish and then average them out but you still are nowhere close to a real test result. Since I'm playing around with making my own fins I kept thinking about how to scientifically testing them. Nowadays you see many board or fin manufacturers telling you "my fin's / board's tracking is a 9/10 and the stability is a 7/10 but what does that really mean? 9/10 in comparison to what? Here a couple of thoughts I had for testing boards or fins
First off I would take the paddler out of the equation and use a electric motor with a propeller or even a RC boat. Something that gets the board with either weights or the paddler sitting on it (center of gravity at the position of the handle) to around 6mph
Board speed:
Install the motor on the back of the board and see which board reaches the highest speed using the same fin and the same weight on the board
Drag:
Bring the board up to 5 or 5.5mph and measure the current on the motor. This way you'll see with which board the motor uses the most juice to keep the preset speed
Glide:
Bring the board to a preset speed, turn the propulsion off and measure the time till the board slows down to let's say 3 or 4 mph. You can also measure the distance from the point you're turning off the motor
Tracking:
Mount the propulsion to the middle on either side of the board. When you turn on the motor you'll go in circles. Use a GPS tracker on your phone and see which board or fin creates the biggest radius circles.
Stability:
This one is really difficult to measure. The ideal situation for this would be a wave pool. Even there you can't really simulate all conditions you'd encounter. I do have a couple other ideas on how to measure stability but that would get very technical and very expensive very fast.

You could also get fancy in these tests and use a frequency generator to simulate paddle strokes with cycling the engine on and off.

I'd also love if manufacturers would give you a value for the amount if rocker a board has. Just take the radius of the rocker for example. Different topic though.

Rob

Quote from: Foilman on July 03, 2016, 08:39:19 AM
I was reading this test and have to say it's at best semi scientific. The biggest variable, the paddler is not taken out of this test. Not only do you have the conditions as a variable but also the paddler. You can do as many test runs as you wish and then average them out but you still are nowhere close to a real test result. Since I'm playing around with making my own fins I kept thinking about how to scientifically testing them. Nowadays you see many board or fin manufacturers telling you "my fin's / board's tracking is a 9/10 and the stability is a 7/10 but what does that really mean? 9/10 in comparison to what? Here a couple of thoughts I had for testing boards or fins
First off I would take the paddler out of the equation and use a electric motor with a propeller or even a RC boat. Something that gets the board with either weights or the paddler sitting on it (center of gravity at the position of the handle) to around 6mph
Board speed:
Install the motor on the back of the board and see which board reaches the highest speed using the same fin and the same weight on the board
Drag:
Bring the board up to 5 or 5.5mph and measure the current on the motor. This way you'll see with which board the motor uses the most juice to keep the preset speed
Glide:
Bring the board to a preset speed, turn the propulsion off and measure the time till the board slows down to let's say 3 or 4 mph. You can also measure the distance from the point you're turning off the motor
Tracking:
Mount the propulsion to the middle on either side of the board. When you turn on the motor you'll go in circles. Use a GPS tracker on your phone and see which board or fin creates the biggest radius circles.
Stability:
This one is really difficult to measure. The ideal situation for this would be a wave pool. Even there you can't really simulate all conditions you'd encounter. I do have a couple other ideas on how to measure stability but that would get very technical and very expensive very fast.

You could also get fancy in these tests and use a frequency generator to simulate paddle strokes with cycling the engine on and off.

I'd also love if manufacturers would give you a value for the amount if rocker a board has. Just take the radius of the rocker for example. Different topic though.

Rob

I'm not sure whether you are talking about what I did or what Larry did. However, I personlly included one test which did isolate the board from the paddler. However I have talked about this with Larry (and others) and there is a pretty good argument why you would want a paddler involved (as both technique and bodymass are integral to a boards performance). There is also a good argument why you need someone paddling as a board pitches, yaws and rolls and testing the board alone without considering that is not actually a true reflection of the board itself when placed in actual context.

To suggest something is or is not scientific really comes to to whether any test follows the scientific method.

1) Is the data repeatable ?
2) Does the data have accuracy and precision ?
2) Is the study repeatable by others ?
3) Are the limitations discussed and stated ?
4) Is the study design relevant to what is being asked or what is intended to be found out ?

I can't speak for Larry but my own tests cover 1-3. Whether my tests satisfy no.4 is always up for debate. 

As I've said, my focus was to ensure the testing was robust (the boards themselves was not relevant). Larry's testing was different and I've added some more robustness to what he did on his facebook page but he acknowledged he needed more runs and I think that would help.

Quote from: Foilman on July 03, 2016, 08:39:19 AM
I was reading this test and have to say it's at best semi scientific. The biggest variable, the paddler is not taken out of this test. Not only do you have the conditions as a variable but also the paddler. You can do as many test runs as you wish and then average them out but you still are nowhere close to a real test result. Since I'm playing around with making my own fins I kept thinking about how to scientifically testing them. Nowadays you see many board or fin manufacturers telling you "my fin's / board's tracking is a 9/10 and the stability is a 7/10 but what does that really mean? 9/10 in comparison to what? Here a couple of thoughts I had for testing boards or fins
First off I would take the paddler out of the equation and use a electric motor with a propeller or even a RC boat. Something that gets the board with either weights or the paddler sitting on it (center of gravity at the position of the handle) to around 6mph
Board speed:
Install the motor on the back of the board and see which board reaches the highest speed using the same fin and the same weight on the board
Drag:
Bring the board up to 5 or 5.5mph and measure the current on the motor. This way you'll see with which board the motor uses the most juice to keep the preset speed
Glide:
Bring the board to a preset speed, turn the propulsion off and measure the time till the board slows down to let's say 3 or 4 mph. You can also measure the distance from the point you're turning off the motor
Tracking:
Mount the propulsion to the middle on either side of the board. When you turn on the motor you'll go in circles. Use a GPS tracker on your phone and see which board or fin creates the biggest radius circles.
Stability:
This one is really difficult to measure. The ideal situation for this would be a wave pool. Even there you can't really simulate all conditions you'd encounter. I do have a couple other ideas on how to measure stability but that would get very technical and very expensive very fast.

As I've already mentioned, there had been a study which towed kayaks off a beam towed from a speedboat. A load cell measures the difference in force between them. That should work but you need to ensure the board would be positioned out of its wake or either wave and it doesn't account for board roll, yaw or pitch. You could argue that this has isolated the board but not the full extent of its behavior in use.

To test fins though (and its on my own list itself) you have to think whats important and design a test or tests from that. I'd suggest:

- Test to identify hydrodynamic drag (with or without the paddler). I did a slow down test which is similar to what you describe above but I would do tests too that involve paddling.
- Stability (I pulled off an app last week that allows you to use the iPhones accelermetors. Mount the phone on a deck and then record the exact level of roll and compare the data over a set number of test intervals.
- I think its also worth talking about how to identify the effect of forward drive of a fin (a large fin for stronger paddlers might be advantageous - even if the drag is greater than a small one).

"Forward drive"? Can you explain the physics of what you mean here? The concept of "drive" in respect of fins is usually associated with wave-riding not flat water paddling.

Quote from: Area 10 on July 04, 2016, 01:06:53 AM
"Forward drive"? Can you explain the physics of what you mean here? The concept of "drive" in respect of fins is usually associated with wave-riding not flat water paddling.

Any resulting force that then helps forward motion. I'm assuming this is the same as lift from the foil.

Ignore the older date and obvious sales pitch from Becker but he touches on it here: http://www.ridingbumps.com/2013/10/08/guide-to-sup-race-fin-selection/

I don't quite understand the drive thing on flat water??? I have never done any testing but I would think the amount of lift created from a standard style fin would be very small indeed. I would be interested to see if they do or not. It wouldn't be too hard to do test but at the moment I don't have time.

Quote from: supuk on July 04, 2016, 01:24:34 AM
I don't quite understand the drive thing on flat water??? I have never done any testing but I would think the amount of lift created from a standard style fin would be very small indeed. I would be interested to see if they do or not. It wouldn't be too hard to do test but at the moment I don't have time.

How would you suggest you test for it ?

You want to be careful there ukgm: fins are a topic where discussions often require a suspension of disbelief, and there are a lot of people around making money out of people's willingness to do so IMO. It's one thing to discuss fin matters in relation to movement on a wave face, but something else altogether to talk about flat water, beyond some basics which are pretty straightforward. Unless someone can explain to me the physics (at even a rudimentary level) of an effect that is being attributed to a fin, my BS detector starts to show interest. The article you give a link to provides no plausible explanation.

Quote from: Area 10 on July 04, 2016, 01:42:47 AM
You want to be careful there ukgm: fins are a topic where discussions often require a suspension of disbelief, and there are a lot of people around making money out of people's willingness to do so IMO. It's one thing to discuss fin matters in relation to movement on a wave face, but something else altogether to talk about flat water, beyond some basics which are pretty straightforward. Unless someone can explain to me the physics (at even a rudimentary level) of an effect that is being attributed to a fin, my BS detector starts to show interest. The article you give a link to provides no plausible explanation.

Yep, agreed. I knew of forward drive back in my sailing days from foils and whilst aerodynamic lift is a factor (and equally turbulent discussion in sports aerodynamics in actual practice), I have no idea how large the hydrodynamic effect would be and how I would test for it. I would ask questions whether the stochastic and low speed nature of SUP paddling could generate it when compared to something more steady state but since I prioritise stability over drag when it comes to fin choice, my musings might all be a moot point.

Quote from: ukgm on July 04, 2016, 01:31:45 AM

Quote from: supuk on July 04, 2016, 01:24:34 AM
I don't quite understand the drive thing on flat water??? I have never done any testing but I would think the amount of lift created from a standard style fin would be very small indeed. I would be interested to see if they do or not. It wouldn't be too hard to do test but at the moment I don't have time.

How would you suggest you test for it ?

just need to have the fin in some sort of box with a force gauge or maybe I micrometer just to see if it moves at all.

Quote from: ukgm on July 04, 2016, 02:02:00 AM

Quote from: Area 10 on July 04, 2016, 01:42:47 AM
You want to be careful there ukgm: fins are a topic where discussions often require a suspension of disbelief, and there are a lot of people around making money out of people's willingness to do so IMO. It's one thing to discuss fin matters in relation to movement on a wave face, but something else altogether to talk about flat water, beyond some basics which are pretty straightforward. Unless someone can explain to me the physics (at even a rudimentary level) of an effect that is being attributed to a fin, my BS detector starts to show interest. The article you give a link to provides no plausible explanation.

Yep, agreed. I knew of forward drive back in my sailing days from foils and whilst aerodynamic lift is a factor (and equally turbulent discussion in sports aerodynamics in actual practice), I have no idea how large the hydrodynamic effect would be and how I would test for it. I would ask questions whether the stochastic and low speed nature of SUP paddling could generate it when compared to something more steady state but since I prioritise stability over drag when it comes to fin choice, my musings might all be a moot point.

If this is the situation you are facing then you will probably find that you are faster on a more stable board with a low drag fin than a theoretically faster (but less stable) board with a big fin to compensate for the loss of stability.

Incidentally, it is interesting to look at the variance in speed through the stroke according to board design. For instance, hybrid-type (prone paddleboard nose) designs tend - I think - not to achieve the same peak speed, but they also tend not to slow down as much through the recovery. This may suggest that different strokes may work for different boards. It's an interesting area for enquiry that has been noted by some shapers but never to my knowledge properly investigated for SUP.

Quote from: Area 10 on July 04, 2016, 03:04:47 AM

Incidentally, it is interesting to look at the variance in speed through the stroke according to board design. For instance, hybrid-type (prone paddleboard nose) designs tend - I think - not to achieve the same peak speed, but they also tend not to slow down as much through the recovery. This may suggest that different strokes may work for different boards. It's an interesting area for enquiry that has been noted by some shapers but never to my knowledge properly investigated for SUP.

Yes I have heard that too from some paddlers as well. I know of one sponsored rider who moved from a Starboard to a Fanatic and had to modify his cadence to get the best from the new board. I suspect a lot of this could be purely accounted for by finding out how good the glide is between boards and then realising that a board with poorer glide needs a higher stroke cadence to keep its speed 'topped up'. If you use a slower heavier stroke, the board will be compounded by its higher drag and drop too much in speed between strokes and wastes energy to get it going again (as we ll as the time loss). That makes sense to me and if seen notably in cycling such as mtb XC or high speed riding when the cubed effect of air resistance is working against you so much that even dropping your torque an inch really hurts your speed or when over rough ground you have momentum or rolling resistance hurting your steady state attempt at power output.

You could map a boards decceleration and see at what speeds this drag is greatest and then that also might mean not only does the board generally require a different cadence to what you're used to but might only be an issue with certain paddlers at certain speeds.

That would be conventional wisdom, yes. But actually I am beginning to suspect that it isn't really like that. It's largely about pitch changes through the stroke, I suspect. If you wanted to revolutionise how we think about SUP designs maybe you'd work with a talented shaper like supuk to create boards with interchangeable noses and rails (like supuk is already doing) and then festoon the board with monitoring devices in order to model the movement of the board in all axes as it moves through the water at different parts of the stroke. I suspect you'd find the results surprising. It would be great to have people applying a bit of science to the "gut feel" of SUP shapers, and it could result in much better board designs.

Quote from: Area 10 on July 04, 2016, 05:24:04 AM
That would be conventional wisdom, yes. But actually I am beginning to suspect that it isn't really like that. It's largely about pitch changes through the stroke, I suspect. If you wanted to revolutionise how we think about SUP designs maybe you'd work with a talented shaper like supuk to create boards with interchangeable noses and rails (like supuk is already doing) and then festoon the board with monitoring devices in order to model the movement of the board in all axes as it moves through the water at different parts of the stroke. I suspect you'd find the results surprising. It would be great to have people applying a bit of science to the "gut feel" of SUP shapers, and it could result in much better board designs.

Yep, I like that !

You might recall the "schnozz" replaceable noses I made a few years back. My goal wasn't science. It was to make a dw board work in flatwater. Didnt work well. The nose needs a bottom profile that works with it. At leasr that was my conclusion. Might just have been some shitty fabrication.

Quote from: Area 10 on July 04, 2016, 05:24:04 AM
That would be conventional wisdom, yes. But actually I am beginning to suspect that it isn't really like that. It's largely about pitch changes through the stroke, I suspect. If you wanted to revolutionise how we think about SUP designs maybe you'd work with a talented shaper like supuk to create boards with interchangeable noses and rails (like supuk is already doing) and then festoon the board with monitoring devices in order to model the movement of the board in all axes as it moves through the water at different parts of the stroke. I suspect you'd find the results surprising. It would be great to have people applying a bit of science to the "gut feel" of SUP shapers, and it could result in much better board designs.

By the way, something I found as I trawled the literature the other week ties in with Larry's 'stroke effectiveness' metric is this paper here which you can all view. It's a little dry so be prepared to have to chew your way through it.

http://www.biorow.com/Papers_files/2006%20ISBS%20Rate-DPS-Speed.pdf

This 'stroke index' (SI) as such has been evaluated successfully in kayaking, canoeing, swimming and rowing.

Interesting paper uk.  I think that measure has use, but I can see if being miss-used easily. 

The assumption that the unknown k factor is equal across 2 combinations of SR and SD needs to be carefully managed. What makes me uncomfortable is that it assumes that k doesn't change as the speed changes, this might be true for rowing skiff and flat water canoes which have a much more optimal hull shape. Even then the analysis they provided seems to indicate a tail off in the model as speed goes up.  I'd be really interested to see if this model has been cross checked across a wider range of data and boat types.

Quote from: Area 10 on July 04, 2016, 01:06:53 AM
"Forward drive"? Can you explain the physics of what you mean here? The concept of "drive" in respect of fins is usually associated with wave-riding not flat water paddling.

Simply put - the fin adds directional stability which could be called 'forward drive'

Similar to a centre board on a dinghy. It takes the energy from the sail and transmutes it into forward drive.

Of course - get a rudder on and all that crap goes out the window :)

Quote from: Area 10 on July 04, 2016, 01:42:47 AM
You want to be careful there ukgm: fins are a topic where discussions often require a suspension of disbelief, and there are a lot of people around making money out of people's willingness to do so IMO. It's one thing to discuss fin matters in relation to movement on a wave face, but something else altogether to talk about flat water, beyond some basics which are pretty straightforward. Unless someone can explain to me the physics (at even a rudimentary level) of an effect that is being attributed to a fin, my BS detector starts to show interest. The article you give a link to provides no plausible explanation.

It's simple - not every part of the stroke adds forward thrust.. The fin helps by transmutting your energy into a straight line. Without the fin you'll need loads more correction stroke and even less forward direction.

Quote from: supuk on July 04, 2016, 02:06:14 AM

Quote from: ukgm on July 04, 2016, 01:31:45 AM

Quote from: supuk on July 04, 2016, 01:24:34 AM
I don't quite understand the drive thing on flat water??? I have never done any testing but I would think the amount of lift created from a standard style fin would be very small indeed. I would be interested to see if they do or not. It wouldn't be too hard to do test but at the moment I don't have time.

How would you suggest you test for it ?

just need to have the fin in some sort of box with a force gauge or maybe I micrometer just to see if it moves at all.

Moves for certain - seen it in my test pool

Quote from: UKRiverSurfers on July 09, 2016, 12:17:44 AM

Quote from: Area 10 on July 04, 2016, 01:42:47 AM
You want to be careful there ukgm: fins are a topic where discussions often require a suspension of disbelief, and there are a lot of people around making money out of people's willingness to do so IMO. It's one thing to discuss fin matters in relation to movement on a wave face, but something else altogether to talk about flat water, beyond some basics which are pretty straightforward. Unless someone can explain to me the physics (at even a rudimentary level) of an effect that is being attributed to a fin, my BS detector starts to show interest. The article you give a link to provides no plausible explanation.

It's simple - not every part of the stroke adds forward thrust.. The fin helps by transmutting your energy into a straight line. Without the fin you'll need loads more correction stroke and even less forward direction.

You are talking about increased tracking. This is not what some fin manufacturers are claiming. They talk about increases in "lift", creating forward thrust. Quite different.

One possible link to what they mean might come from the effect of transferring weight from side to side on a windsurfer. I do not windsurf, but a friend of mine who does maintains that with certain fin setups in no wind he can generate some forward movement of the board by doing this. He reckons that this may be what the fin makers are talking about. I can't quite see how this relates to flat water speed on a SUP since conventional wisdom has it that it is fastest to keep an even keel. But I'm keeping an open mind on it. I just get suspicious when claims are made without any explanation of them at even the most basic level. Sometimes the fin brands will say that they don't explain because they don't want to give their secrets away to competitors. But there are other possible explanations for not explaining claims too...