Standup Zone Forum
Stand Up Paddle => Gear Talk => Topic started by: PonoBill on September 18, 2016, 12:35:16 PM
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Kind of a crappy day in Hood river--perfect for fin testing. I installed one of Larry Allison's ventral fins yesterday, and I have a bunch of other fins to try on my Blackfish. I kind of screwed up the finbox install, I was trying to keep it neat and make the patch small, but the 4OZ I laid over the carbon got a bubble in it while I wasn't watching and I had to sand it all off and redo it. Crap. Oh well, the box is in the right place and it's laser straight, so I got that going for me.
(http://www.theretirementtrap.com/wp-content/uploads/2016/08/IMG_0825.JPG)
(http://www.theretirementtrap.com/wp-content/uploads/2016/08/IMG_0827.JPG)
Is this the right fin, Larry?
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Bill the small fin is the Ventral all the way back. The other fin is a kick fin for crazy conditions between the Twins. Nice work.
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You're way too serious. Small joke.
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You're way too serious. Small joke.
Let's now hear some feedback on it !
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Okay, this is complicated. There's a surprise. There's about a ten percent speed difference available by playing with fins on this board, which is more than I expected.
I set a baseline by paddling with the stock three fin setup. I tried three different paddles, expecting the Konihi 84 to be fastest as I've seen before. To my surprise the Mana was faster. Might be because I'm adding more of the Puakea stroke to my stroke.
Konihi 95 5.35 mph max, 4.94 average, 4.30 upwind, 5.35 downwind.
Konihi 84 5.50 max, 5.14 average, 4.40 upwind, 5.50 downwind
Mana 90 5.55 max, 5.20 average, 5.10 upwind, 5.55 downwind
I reversed the order of paddle use and got about the same results, so I used the mana for testing.
Stock plus ventral, Mana 90 Max 5.50 5.20 average, upwind 5.20 Downwind 5.50 The ventral fin took a little getting used to. Tracking is better, stability is better,
I tried taking out the center fin with ventral. the difference was too small to list--about the same as three fins plus ventral.
I took the ventral out and ran stock twins only.
Twins no ventral Max 5.65 Average 5.20 Upwind 5.05 Downwind 5.65 This was the fastest setup, contrary to my earlier tests of the standard three fin with no ventral. The board was hard to control and it wandered, but it reached higher speed. I tried some larger "nub" style twins I got from Larry with no change.
Single fin and ventral Max 5.10 Average 4.95 Upwind 4.85 Downwind 5.10 This setup accelerated well but it felt like it reached a maximum speed quickly and then stopped accelerating.
Twin nub fins with small "ventral" between them, no ventral Max 5.50 Average 5.40 Upwind 5.25 Downwind 5.50 This felt really good, accelerated well and held speed easily. Didn't track very well
Twin Nubs with ventral Max 5.50 Average 5.30 Upwind 5.20 Downwind 5.50 Tracked well, didn't feel as easy to hold speed but the results were good.
I was pretty puzzled by all of this, so I tried the Konihi 84 with the twin nub plus ventral
Max 5.65 Average 5.40 Upwind 5.30 Downwind 5.65
By then I was totally confused, and I'm not much less confused now looking at the numbers. From the way things felt, the Konihi paddle works better with the ventral fin than the Mana does. I think I need a teeny ventral fin and a teeny center fin--maybe it just functions as a gate between the two foiled side fins.
The ventral fin adds stability and tracking and doesn't cost any significant amount of performance. I think for anything but a downwind race it would be an obvious choice. There's definitely performance to be gained with multi fin setups, but it's going to take some experimenting to get all of it. I think course conditions and paddle choice may go along with fin choice. Which seems like something surfers have known forever.
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Okay, this is complicated. There's a surprise. There's about a ten percent speed difference available by playing with fins on this board, which is more than I expected.
I set a baseline by paddling with the stock three fin setup. I tried three different paddles, expecting the Konihi 84 to be fastest as I've seen before. To my surprise the Mana was faster. Might be because I'm adding more of the Puakea stroke to my stroke.
Konihi 95 5.35 mph max, 4.94 average, 4.30 upwind, 5.35 downwind.
Konihi 84 5.50 max, 5.14 average, 4.40 upwind, 5.50 downwind
Mana 90 5.55 max, 5.20 average, 5.10 upwind, 5.55 downwind
I reversed the order of paddle use and got about the same results, so I used the mana for testing.
Stock plus ventral, Mana 90 Max 5.50 5.20 average, upwind 5.20 Downwind 5.50 The ventral fin took a little getting used to. Tracking is better, stability is better,
I tried taking out the center fin with ventral. the difference was too small to list--about the same as three fins plus ventral.
I took the ventral out and ran stock twins only.
Twins no ventral Max 5.65 Average 5.20 Upwind 5.05 Downwind 5.65 This was the fastest setup, contrary to my earlier tests of the standard three fin with no ventral. The board was hard to control and it wandered, but it reached higher speed. I tried some larger "nub" style twins I got from Larry with no change.
Single fin and ventral Max 5.10 Average 4.95 Upwind 4.85 Downwind 5.10 This setup accelerated well but it felt like it reached a maximum speed quickly and then stopped accelerating.
Twin nub fins with small "ventral" between them, no ventral Max 5.50 Average 5.40 Upwind 5.25 Downwind 5.50 This felt really good, accelerated well and held speed easily. Didn't track very well
Twin Nubs with ventral Max 5.50 Average 5.30 Upwind 5.20 Downwind 5.50 Tracked well, didn't feel as easy to hold speed but the results were good.
I was pretty puzzled by all of this, so I tried the Konihi 84 with the twin nub plus ventral
Max 5.65 Average 5.40 Upwind 5.30 Downwind 5.65
By then I was totally confused, and I'm not much less confused now looking at the numbers. From the way things felt, the Konihi paddle works better with the ventral fin than the Mana does. I think I need a teeny ventral fin and a teeny center fin--maybe it just functions as a gate between the two foiled side fins.
The ventral fin adds stability and tracking and doesn't cost any significant amount of performance. I think for anything but a downwind race it would be an obvious choice. There's definitely performance to be gained with multi fin setups, but it's going to take some experimenting to get all of it. I think course conditions and paddle choice may go along with fin choice. Which seems like something surfers have known forever.
How many times did you repeat each fin test? Wondering what the signal to noise ratio is with your speeds being spread out like that
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I didn't repeat them at all. took two hours as it was.
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Testing is such a damn hard thing to do. Takes forever just to test two different options. And it takes many repeats, and ideally many different testers to be really convincing. Who has time and energy for that?
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It is hard enough doing one max speed sprint test. Let alone multiple. I found the more I did -> the slower and more inconsistent the results became. The fastest time was always the first for me.
What I found more interesting was the GPS track plotted using different fins. My findings were quite interesting nonetheless and those inclined should do tests of their own. My tests were done over a number of days with different boards and fins - but same paddle. It did help provide some clarity though. But not something I ever want to repeat.
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Alright Bill super Stoked to have you taste what I live. Try adding 12 more guys and different global locations and then compare notes from all locations on top of my water time understanding the different mind sets of everyone before making my conclusion. This in some case takes me up to 8 month like the testing we just went thru with same plan shape but different structure, Fiberglass, Honeycomb, Honeycomb/ carbon and foam/carbon. As you see for those who know me I am very anal to not contradict myself like my competitors that change their mind every 6 months. Fun stuff when reality surprises you.
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The test results above are in the order I did the tests. I got my highest speed on my ninth test (six paddle tests, third fin variation) and then equalled it on the thirteenth test. I'm not a sprinter, I'm a grinder. Diesel motor.
I was pleased to see that the ventral fin doesn't interfere with turning the board. With twin fins the tail is stable enough to easily lift the nose and pivot, but it also footsteers as well or better with the ventral fin than without, and a cross-bow draw works very well and is stable.
I like the feel of the four fin setup. I think I just need to tune it up on size. There needs to be a lending library for fin testing. I'm seeing a ten percent variation in speed just with basic testing with a few fin variations. I'm sure there's a little more. Ten percent is mid-pack to podium for a lot of racers.
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Interestingly over distances like 5 miles or so my GPS times are very repeatable based on around 90% exertion levels. ie. near max sustainable exertion levels. The best is that it provides 2 split times over a 3 leg loop to compare as well. Provides real good data points to confirm perceived vs actual effort over each leg with HRM. That sort of speed test has worked really consistent for me over the years. And provides good information as my times have dropped year over year.
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Yup. It's really only the long tests that matter unless all you do is sprint racing. My performance year to year has steadily improved. Unfortunately, it's improved a lot slower than all those folks around me. Hell, I used to be able to beat Connor Baxter and Travis Baptiste--when they were twelve.
I've seen many times that an apparent improvement in performance doesn't hold true in the long run. The Konihi 84 paddle tests much faster than other paddles. But it only does so for me at a high cadence, which I can't maintain. As soon as my attention wanders it's a very slow paddle.
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Testing is such a damn hard thing to do. Takes forever just to test two different options. And it takes many repeats, and ideally many different testers to be really convincing. Who has time and energy for that?
It can take a while. I can typically test 4 changes in equipment using one kind of test reliably in a 2 hour window. I might repeat that again another day if the data is bunkum or I want re-test stats. I then need 1-2 hours for data analysis. To give you an idea, my current project to test 10 fins is likely to take somewhere in the region of 10-15 hours. It's not just the time, its the weather. You need to pick a venue and know it well enough to wait for optimum or stable weather too.
Yes I do have the inclination to do this kind of thing but then I have a job with a fair degree of flexibility (I'm an academic).
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Interestingly over distances like 5 miles or so my GPS times are very repeatable based on around 90% exertion levels. ie. near max sustainable exertion levels. The best is that it provides 2 split times over a 3 leg loop to compare as well. Provides real good data points to confirm perceived vs actual effort over each leg with HRM. That sort of speed test has worked really consistent for me over the years. And provides good information as my times have dropped year over year.
It depends what you're after. Personally, I'd recommend a test speed that is representative of someones typical racing speed but sub max is a good call. Either way, I'm a strong exponent of using 'stroke index' (average speed x stroke length) as my key metric. This is a key and well cited metric in sports journal literature that require propulsion such as swimming and canoeing. It does mean the results are unique to the user but nobody will get a robust sample volume anyway (and all anyone will care about is will it make them faster anyway). What I've learnt is not to test at sprint speeds. Whilst this can really expose the differences between equipment (due to the exponential increase in drag), it generally leads to a poor stroke quality, be misrepresentative of your racing and this can ruin the results.
For what it's worth, I don't do any less than 6 test runs (typically around eight and will often junk one) and I have been getting a coefficient of variation of my fin test data sets (standard deviation / mean *100) of 1% and that's as good as a science lab. Getting good data is possible with patience.
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I've seen many times that an apparent improvement in performance doesn't hold true in the long run. The Konihi 84 paddle tests much faster than other paddles. But it only does so for me at a high cadence, which I can't maintain. As soon as my attention wanders it's a very slow paddle.
It depends. That aspect may be trainable over time in use or with an an improvement in aerobic fitness.
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And it takes many repeats, and ideally many different testers to be really convincing.
It does require many repeats but the literature has shown that you can test as short as 350m and still pick up the differences. I have managed this with boards, paddles and most recently fin changes. Secondly, it only requires different testers if you want the findings to be applicable to a wider population (probably most manufacturers would want this but you won't) . If you want the findings to be applicable to you, I would just suggest merely testing on more than one occasion and correlating one set of data against the other (this is built into Microsoft Excel).
As someone will rightfully point out sooner or later, there is also the problem with the placebo effect. To reduce its impact, testing with multiple paddlers can help but doing a test/retest yourself can also highlight if you have a problem. To also help, one of the tests I use is a coast down test which is whereby you measure the deacceleration (and therefore the boards drag) by performing 15 maximum strokes on one side and then taking the paddle out and gliding to a stop. By working out how quickly the board slows down puts Sir Isaac Newton in the driving seat, not you, and will then show the differences in drag (although not whilst actually paddling). You'll need a GPS unit with the highest sampling rate you can find but this is a cheap alternative for those that don't have the means to work out stroke length.
If you haven't tried testing in flat and calm conditions and you're using a single test run in messy, chaotic conditions, It's highly probable that the data is poor (or that the statistical error could be so high to shroud the true result). I'm putting together an article soon on what I've found out once I finish testing the last of my 10 fins this week but I've seen some interesting things so far.
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I'm seeing a ten percent variation in speed just with basic testing with a few fin variations. I'm sure there's a little more. Ten percent is mid-pack to podium for a lot of racers.
Configuration changes may yield an unknown or untapped level of performance. However, I've currently tested single set ups comprising cheap fins to the most expensive on the market and I'd say so far I'm not seeing anywhere near 10% when looking at the stroke index. Probably closer to a third of that on flat water. A 10% variation would raise my eye brows and not pass my own testing sniff test. I'd certainly recommend retesting your two best options (or the very best and worst) and re-confirm for your own piece of mine. Bear in mind you've only been using single runs and that carry some risks. I had to bin a whole session the other week whereby I found that my test speed was slightly too high and was generating stroke quality fatigue through the battery of tests (I also discovered I need a lengthy warm up phase before my stroke quality establishes itself and stabilises.
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I also discovered I need a lengthy warm up phase before my stroke quality establishes itself and stabilises.
Yeah, I noticed that yesterday. I did the paddle tests twice, and it helped get my stroke stabilized.
I'm concerned about the big speed difference as well. A good single fin is what every other board I've used relies on. It's pretty calm this morning, I'm going to go run another series and include a couple of single fin variations.
I assume that your coast down tests run from some set speed to a slower speed. I won't be surprised to find the multiple fins have more drag. In fact I'll be shocked if they don't.
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I also discovered I need a lengthy warm up phase before my stroke quality establishes itself and stabilises.
I assume that your coast down tests run from some set speed to a slower speed. I won't be surprised to find the multiple fins have more drag. In fact I'll be shocked if they don't.
They aim to (hence the fixed number of strokes and the side paddling) but there is some minor variation. I make the assumption that the de-acceleration is linear (which it isn't but at these slow speeds will be close enough). I will say though, I haven't tried that test with fins yet (only boards). It should work but I might not get the sensitivity it needs. I'm just waiting on the last fins to come in from one last company before I do those and try it out. If it doesn't work, I'm not too worried as i've had great results so far from the usual 350m stroke index trials.
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I also discovered I need a lengthy warm up phase before my stroke quality establishes itself and stabilises.
Yeah, I noticed that yesterday. I did the paddle tests twice, and it helped get my stroke stabilized.
I'm concerned about the big speed difference as well. A good single fin is what every other board I've used relies on. It's pretty calm this morning, I'm going to go run another series and include a couple of single fin variations.
I assume that your coast down tests run from some set speed to a slower speed. I won't be surprised to find the multiple fins have more drag. In fact I'll be shocked if they don't.
Slower speeds not the case Bill. Check this video of the Starboard I just did with 4 fin. This guy is over 6'2" 230 lbs and notice the glide. the owner of the board is 165Lbs and said he had to work to get it to speed with a single fin at the box placement it came.
https://www.youtube.com/watch?v=Gs2P-Vfdfl0
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I was referring to the coastdown test that UK is doing, starting at some specific speed and timing how long it takes to get to a slower speed as an measurement of total drag. I think (and it's just a guess) that multiple fins have more drag, but that they permit higher speed in spite of the greater drag by making the board track better and paddle more efficiently. The test will give a basic verification of whether this is true or not. My test this morning (very short, it was cold!) verified that the multi-fin setup is faster for me, even over a fairly long distance.
I did a single fin with no ventral and paddled it 1/4 of a mile (after warmup). the highest speed I saw on my Paddle Coach was 4.9 mph and average was around 4.7. I paddled back slowly, rested a bit, paddling around, and did the same course with the two nub fins you sent (I don't know what they are called) plus the small stock fin and the ventral fin. Highest speed was 5.55 and average was around 5.2. I'm going to do UK's approach of average speed times stroke length once i download the data. But roughly speaking, the difference between the two fin setups was .65 max speed and .5 average. I did the multifin test second, and I think the course was long enough to overcome a placebo effect--or at least mitigate it. That's a ten percent difference--actually 13.8 percent max speed and 10.6 percent average, which I still think is unlikely, but it's pretty cool.
I used the Konihi 84 paddle, concentrated on keeping my cadence up and pushing down on the paddle as Johnny Puakea recommends. If anything I pushed harder on the single fin, thinking "come on! I have to at least break 5.0". But I didn't.
If more fins equals the same or less drag it would be very weird, but we'll see. I'll do the coastdown test when Hood river warms up over the next few days.
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I was referring to the coastdown test that UK is doing, starting at some specific speed and timing how long it takes to get to a slower speed as an measurement of total drag. I think (and it's just a guess) that multiple fins have more drag, but that they permit higher speed in spite of the greater drag by making the board track better and paddle more efficiently. The test will give a basic verification of whether this is true or not. My test this morning (very short, it was cold!) verified that the multi-fin setup is faster for me, even over a fairly long distance.
I did a single fin with no ventral and paddled it 1/4 of a mile (after warmup). the highest speed I saw on my Paddle Coach was 4.9 mph and average was around 4.7. I paddled back slowly, rested a bit, paddling around, and did the same course with the two nub fins you sent (I don't know what they are called) plus the small stock fin and the ventral fin. Highest speed was 5.55 and average was around 5.2. I'm going to do UK's approach of average speed times stroke length once i download the data. But roughly speaking, the difference between the two fin setups was .65 max speed and .5 average. I did the multifin test second, and I think the course was long enough to overcome a placebo effect--or at least mitigate it. That's a ten percent difference--actually 13.8 percent max speed and 10.6 percent average, which I still think is unlikely, but it's pretty cool.
I used the Konihi 84 paddle, concentrated on keeping my cadence up and pushing down on the paddle as Johnny Puakea recommends. If anything I pushed harder on the single fin, thinking "come on! I have to at least break 5.0". But I didn't.
If more fins equals the same or less drag it would be very weird, but we'll see. I'll do the coastdown test when Hood river warms up over the next few days.
It sounds good and I'm very interested to hear how you get on. My suggestion would be to decide on a target stroke cadence (that's how Larry Cain does it) or use a target speed (how I do it). It doesn't matter which one you pick. I use speed as I know what speed is typical of my racing and my various exercise intensities. Try both boards on flat, calm water first and do a few short runs of a couple of minutes in length will tell you a lot. Don't get hung up or overthink the data at the time - just do the paddling and then crunch the numbers when you get home.
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It is great that you are doing this, and I am following the results with interest. But a 10% difference in speed with a different fin setup doesn't sound very likely to be genuine. Or at least, it might be highly specific to you. 10% is about twice the size of the difference you'd get comparing a 12-6 to a 14ft board.
More likely to be a placebo effect, or just random error variance I'd have thought. But it does highlight how important it is to have multiple repeated measurements, and several people doing the testing - ideally blind. In other words, testing differences in gear is a lengthy and difficult business, if you really want to be sure that it's not all in your mind, or just luck.
PB - Why were your speeds so slow with the single fin? A man of your experience (even allowing for your weight on a 14) in flat windless conditions should be averaging faster than 4.7 mph over a quarter of a mile, unless you were just cruising. Maybe you weren't quite fully warmed up yet?
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10% is about twice the size of the difference you'd get comparing a 12-6 to a 14ft board.
More likely to be a placebo effect, or just random error variance I'd have thought.
Yep, that's typically around 6% I've found when looking at race data over here.
My feeling is that's just the issue when you only use one test run which then has a margin of error based upon the paddling conditions attached to it. Either that or one board might be a real struggle to be used (not in this case but for example if a paddler was used to a 28 inch wide board and then tried a 21.5).
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I agree, it's way too much, something's wrong. I probably didn't warm up enough. I was pissed that I couldn't seem to get past 5 mph I'll do it again today and do multiple tests. I only have to test two variations so that shouldn't be too much of a burden. I hope it's a little warmer. I sound like a sissy saying that it was cold when it was only 62, but it was one of those blustery, grey, early fall days that make you look for a book and a fire.
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I agree, it's way too much, something's wrong. I probably didn't warm up enough. I was pissed that I couldn't seem to get past 5 mph I'll do it again today and do multiple tests. I only have to test two variations so that shouldn't be too much of a burden. I hope it's a little warmer. I sound like a sissy saying that it was cold when it was only 62, but it was one of those blustery, grey, early fall days that make you look for a book and a fire.
Don't worry about it. Re-test, confirm your data and bask in the glory of your results !
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I got 5.9% faster on our AS23 compared to Dom27.5 after 3 tests going at sub max. Interestingly the main gains were derived going upwind. Crosswind and DW the board was a touch slower on average. For some reason that AS23 goes real fast upwind.
My thoughts are it has to do with big concave providing lift vs the displacement rolled vee. My tests were done very early on when my balance was poor on the AS23. Even though it seemed a lot of nervous energy was being expended on balance - the amount reflected on the speeds was small. Would expect my speed to be faster again now. For sure Connor can go extremely fast on this and the 21.5 Sprint. If I can feel somewhat stable on the AS23 now -> it must feel crazy stable to him and other top SB pros.
Run 1 was 4.1% slower
Run 2 was 1.6% faster
Run 3 was 5.9% faster
I always find analyzing any test results to be very interesting. Much can be teased out between the lines that is not apparent at first glance.
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People at one point when they fully understand the dynamics in a multiple fin world in Standup get it after they ride it. But first people need to understand a Standup world and not compare it to surfing or windsurfing, I know because I came from both of those worlds and I was a Single Fin Surfer McCoy rider Lazor Zap and Horan, but in the Standup world I will always be multiple fins.
Here's a review from a new guy in Maryland that went thru the pressure from people saying SINGLE FIN MAN!!!! Then after intense going back and forth this was his result. I am glad that guys like Ponobill and thousands other have step out and put it under their feet, thank you PonoBill.
Fin selection/board dynamics
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erik kauffman
Larry,
I felt it necessary to share what I've recently felt in the transformation in my board by using the correct fin set up for me...
Being a bigger guy at 6'4" and 245, I felt my options for production boards was limited to just a few which might have the volume to float me at the correct water line. My initial Board selection was a Bark Eliminator. Great float, but I always had that uneasy feeling of roll under foot when I really started to power down. Around that time, I purchased a Gladiator Elite fin. I can honestly say from the first time I screwed that fin in, it completely changed the personality of the board. Stability was dramatically improved, tracking was much better, and for once, the guys I paddle with started to make comments on how fast my starts had become. Or they would comment how fast I could move a 14'x30" through the water in a sprint. Projection, as you always say! I finally had a ridged enough fin on the board with enough surface area that I could push off, moving that energy transference forward. Of course this was all what I felt...
My next major decision in my SUP journey was to get a custom built for me. After going back and forth on a couple builders, I chose to go with Infinity. I left the choice of board design up to Dave B, given my size, ability at that time, board I was riding, and the water I frequently paddle (Chesapeake Bay). He suggested the Cutthroat 14x30. I went with all 4 fin boxes. Ventral, and twin Pro Boxs with a center traditional fin box. It was shipped with a kick fin and the stealth twins... I thought I was supposed to use the kicker as the ventral, the small stealths in the twin Boxs and the elite as my center fin. Talk about OVER FINNED!!! I didn't know any better. Obviously, stability wasn't an issue, the board felt glued to the water! But that was the problem... the board felt glued to the water! Slow, heavy on the pulls, but man, once I built speed behind the stroke, I was a freight train barreling down the tracks! Don't ask me to turn though! I experimented with different center fins, removed the ventral and used that just as the kicker, twins alone... All just to see what "felt" fastest.
Easier feeling pulls, squirrelly handling all "felt" faster... And a GPS watch was capturing pretty impressive numbers on mph and max mph. I thought I was on the right path... But my mile splits were staying fairly consistent. I was back to tracking all over the place when I'd put power down!
After a conversation with you and ordering larger side fins I can say that the best set up I've found for me, my size, my board volume (330 L) is your newest in the line up, the Blackfish twins (4.5x11) with just the kicker as a center and your small ventral in. With this set up I knocked off 22 seconds in my mile splits!!! Today was an outstanding breakthrough!!! Projection, Larry... You say it, I finally understand it through experience. And a Garmin 920XT to quantify the "feel"
I can say that any guy over 220lbs or any board over 290 liters, that should be serious consideration for their set up.
My paddling buddies (who have many more years experience than I do) always say, just put a big single fin in. Sounds logical, but through my experience twins give far greater rail to rail stability than a single fin adding up to the same surface area. With far less deep water disturbance, therefore less wake for someone to draft you on!
I'm happy to share my experience! Thanks again for all your insight, Larry! It's been a great help!
Erik Kauffman
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Was thinking fore aft balance on the AS23 is super critical. Get even a touch too far back and the tail drags like crazy. The board has a very narrow speed sweet spot DW because of the cutting boof. Prefer the surfy fast Bullet 14V2 by a long shot for 10-20 kt breeze. Can stay easily powered up comparatively. And is way more fun.
My sub max speeds are just nominally slower than race speeds - and plenty accurate enough for my purposes. No need to go all out for simple speed tests.
Nonetheless will be interesting to see PB fin results. For my purposes - have no reason to go ventral or 4 fin set-ups because my boards are stable and fast enough even using my smallest fin. The SIC 7.0. But if they help others - then by all means. Cannot imagine ever needing a quad for an AS25 though. That board just rolls a bit but has a ton of secondary stability. But if you need it - you need it. And Larry - still waiting if I can demo a couple of your DW fins and post here about them.
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Can confirm that the Gladiator Elite is an excellent tracking stability fin. Do use it from time to time - as well as the slightly smaller Hybrid for AW. Even DW.
And have tried your ventral and small kicker on a Blackfish 25 without side fins. Found that board to be extremely stable - turned ok - and felt fast. Not my board though - so no timed GPS speed tests. Very nice board and really liked the smoothness with the ventral.
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Yes, that was one of the test variations. Not as fast: 5.10 max, average 4.95 but stability was good and acceleration was good. The blackfish 25 is the test mule for all this.
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Yeah correction - that board I tried was Luc's Eradicator 25 before the present owner bought it from him. And originally was apparently Norm's race custom he used when I paddled with him up Squamish way. Luc did the LA 4 fin mod.
The Blackfish Luc currently has was apparently bought from another local racer I had paddled with on that same DW. Think that was the time I shuttled with Norm. The circle of DW paddlers and racers is very small in these parts. Luc can chime in if different. Have not paddled with Luc in awhile though. Probs a couple of years.
The Blackfish has a very interesting crescent tail. Does it do anything special from what you can tell?
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I don't know. It's been challenging to steer, I'm hoping that's a fin issue. The nose and tail have funny waterflows, the nose especially (since I can see it) does this very random little flow that wraps up the rails and flings into the air like a plugged showerhead. Very odd. So far it's most redeeming quality is that it trims so well with me on it. And it's reasonably fast in flatwater. I like it. I hope I can make it work to my satisfaction for downwind.
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Probs if you have the right fin in there - it should be ok. Lucky for us lightweights - we can trim most boards and balance ok. All our boards have a ton of extra buoyancy. It actually provides heeps of extra stability. But if heavier - yeah very much harder for sure. Paddled with a small boy sitting in front while I paddled the Dom - and could barely make that thing move. So can empathize.
My strength to weight seems really optimized at my current weight. And add just 10 lbs and it would drop a lot. But you seem to be doing ok in your 70s. I am a teenager in comparison. ;)
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PB - at the risk of opening up another can of worms in the. "14fters that big guys can paddle", have you tried the SIC FX14? That seems to be a board that some pretty solidly built guys say trims well for them, and might be the kind of flat water/DW hybrid that might suit your needs, perhaps? Interesting to hear the views of some bigger guys.
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Okay, I spent three hours testing today. Nice day, light wind that picked up enough for one kitefoiler to play.
I made a standard ADD screwup that was kind of revealing. I intended to try the stock center fin, two nubs and ventral combination first. I had left the ventral in the center slot after testing yesterday so I moved it to the ventral slot. Paddling up and down at Nichols the board felt sluggish and I struggled to make it past 5.0. I thought it was just a matter of warming up, so I left the Nichols pond and headed downriver into a light wind. A struggle all the way. I was pushing hard to maintain 4.5 mph. When I got to the beach (where the Gorge Paddle Challenge was held) I thought "this isn't performing as well as the stock setup. I'm going to pull the ventral and see what happens. Pulled in, flipped the board over, no center fin. I thought it might have fallen out, but when I got back to the car I found the center fin on the passenger seat. ADD boy strikes again.
While I was on the beach, I moved the ventral fin back to the center position and started paddling into the wind again. I hit and held 4.9 easily with a few forays above 5.0. Turned around and held 5.5 to 5.7 easily in the little bumps. Back at Nichols I could do 5.55 easily, either direction, and I held above 5.2 generally. I haven't downloaded the data yet so I don't have precise figures. I'll do that tonight.
I tried Single fin and ventral again, got 5.1 with great effort but averaged about 4.9. Pulled the ventral fin and had the same results with less stability.
I tried to do coastdowns, but my method isn't working, and my Paddle Coach isn't helping. I think there's a software glitch, or maybe it's configuration option or a smoothing feature. I was trying to hold 4.5mph for a few seconds, then stop paddling and see how long it took to coast down to 2.0mph. The paddle coach would dither around 4.5, but then when I stopped paddling it would hold a slightly lower value for perhaps ten seconds with no update. Then when the speed got down to about 2.9 mph it would show that and start updating every second. The times I got for coastdown varied all over the place. So that sucked.
What I learned is that the tree fin setup is fast, and it's even faster when the center fin is small. I stopped by Big Winds, hoping they'd have a little ventral fin, but no dice. I'll have to talk to Larry and maybe make something in the meantime. I'm fairly certain that for my use, the two nubs plus a small center fin and an even smaller ventral fin would be the fastest combo. Very stable.
I also noticed that when I was paddling hard with the three fin setup, that the nose of the board moves a little in the direction of the paddle. With a single fin and no ventral the nose moves away from the paddle, and with a single fin and the vental it doesn't move.
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I can't figure out the data. I don't know each configuration starts and stops. I normally would have taken note of the timing, but I had that long paddle in the middle. Ah, screw it, I know what I need to know. That's the problem with screwing up, everything turns to fog.
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I tried to do coastdowns, but my method isn't working, and my Paddle Coach isn't helping. I think there's a software glitch, or maybe it's configuration option or a smoothing feature. I was trying to hold 4.5mph for a few seconds, then stop paddling and see how long it took to coast down to 2.0mph. The paddle coach would dither around 4.5, but then when I stopped paddling it would hold a slightly lower value for perhaps ten seconds with no update. Then when the speed got down to about 2.9 mph it would show that and start updating every second. The times I got for coastdown varied all over the place. So that sucked.
Yep, I had problems with a speedcoach with that. The raw data would only record when I was actually paddling (I guess the accelerometer in it is a trigger) so I'd get data gaps. I've had to switch to using a conventional Garmin 910XT for those tests (I then import it in into Trainingpeaks WKO+ 3.0 software). This seemed to work when I pilot tested it with a couple of fins but the sampling frequency might not be high enough when I do all of the fins.
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I can't figure out the data. I don't know each configuration starts and stops. I normally would have taken note of the timing, but I had that long paddle in the middle. Ah, screw it, I know what I need to know. That's the problem with screwing up, everything turns to fog.
I got into the habit of coming off the water and writing down the distance achieved on a notepad as I switch out each fin or after each run. I also then only paddle slowly between test runs. This allows me to pick up the runs visibly when I pull a CSV file into Microsoft Excel.
It does take time just to get a methodology right and repeatable and it can be frustrating initially. However, it can be rewarding when it goes well. Don't let this dishearten you - it just takes time.
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I'm pretty happy with the results so far, I found out what I wanted to know. I don't understand it at all, but it's useful. I'm fairly certain the magnitude of the difference is wrong, but every test is consistent enough so I'm convinced the difference is real.
Which leads to the real question--how the hell does sticking a little tiny fin in between two fins make the board faster?
That just doesn't make sense to me. The board feels very draggy without it. I can't make two fins without that little fin between them work at all. What the hell is that little fin doing?
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Which leads to the real question--how the hell does sticking a little tiny fin in between two fins make the board faster?
I assume you plugged the empty finbox when you removed it.
I found when testing 2+1 fins in a longboard, there was a spot in the middle box, where the center fin made drag and another spot where it didn't. Felt to me like the middle fin cleaned up flow coming off the side bites when I got it right. I know that is different than your case, since my side bites are toed. Food for thought anyway.
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No, I didn't plug it. The side fins are toed a little, according to my laser the intersection point of the toe is about six feet in front of the nose of the board (about 19' total), so pretty small. I'd convert to degrees, but who cares other than my old trigonometry teacher, who is probably safely dead.
I'm finding this very odd. I think your explanation might be on the money DW, which leads me to wonder how small the fin can be and still get the same result. I'm pretty certain that bigger fins are slower for me (stronger paddlers might not have the same result), but will smaller be faster. I think all the work of making the board track and resisting the torque is being done by the nubs, and the middle fin might just be a flow straightener.
I'm just guessing, but it opens some interesting options. Larry is definitely onto something.
UK, I suspect you're right about the refresh for SpeedCoach being triggered by stroke. Makes sense for what it's made for. I didn't think of tagging fin changes by distance. Duh.
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I'm finding this very odd. I think your explanation might be on the money DW, which leads me to wonder how small the fin can be and still get the same result. I'm pretty certain that bigger fins are slower for me (stronger paddlers might not have the same result), but will smaller be faster. I think all the work of making the board track and resisting the torque is being done by the nubs, and the middle fin might just be a flow straightener.
I'm just guessing, but it opens some interesting options. Larry is definitely onto something.
PonoBill, You said it perfectly.
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Hello Larry/Bill,
Just trying to reconcile this with the size of the central/kick fin having increased over the past years from the original to the current 6" Stinger.
As far as I know the 6" Stinger is the de facto recommended kick fin for the Blackfish.
Does the center fin also provide projection like the ventral or should it be kept smaller as suggested by Bill.
Cheers,
Luc
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Hello Larry/Bill,
Just trying to reconcile this with the size of the central/kick fin having increased over the past years from the original to the current 6" Stinger.
As far as I know the 6" Stinger is the de facto recommended kick fin for the Blackfish.
Does the center fin also provide projection like the ventral or should it be kept smaller as suggested by Bill.
Cheers,
Luc
The conditions even in multiple fin world plays out. If you are in calm,flat water where you have no interference with Mother Nature or running a low volume board that sets deeper in water and are light weight then smaller kick fin.
If Mother Nature plays a roll and conditions are pushing along with a high volume board that sets higher on water along witha strong paddle tongue from rider, then bigger kick. remember concave in the tail like Starboard and Infinity already gives for a larger fin because concave make the fin sit deeper from the water line.
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Got it.
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Hello Larry/Bill,
Just trying to reconcile this with the size of the central/kick fin having increased over the past years from the original to the current 6" Stinger.
As far as I know the 6" Stinger is the de facto recommended kick fin for the Blackfish.
Does the center fin also provide projection like the ventral or should it be kept smaller as suggested by Bill.
Cheers,
Luc
I'm not in any position to give advice. I'm in the dazed and confused category.
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Ponobill,
Install looks good. If you wanted to hide the patchwork on the black carbon boards you can get some Rustoleum black spray enamel and lightly paint it. Wait a day and then wet sand. It blends it right in. I've done a lot of black carbon repairs. Just finished a retro fit on a 2016 Blackish and had to move the ventral box for the owner back toward the balance point about 12".
The White boards make it very easy to hide the repairs and fin box installs. This one I will paint once I test ride the board and make sure it worked for the owner.
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Hello Larry/Bill,
Just trying to reconcile this with the size of the central/kick fin having increased over the past years from the original to the current 6" Stinger.
As far as I know the 6" Stinger is the de facto recommended kick fin for the Blackfish.
Does the center fin also provide projection like the ventral or should it be kept smaller as suggested by Bill.
Cheers,
Luc
I'm not in any position to give advice. I'm in the dazed and confused category.
Bill I think you are the exact guy for advice, because you are feeling what I have been tryng to explain and more importantly by your comments you are speaking fin SUP language. There is alot going on but becomes simple when you understand the language my friend.
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Ponobill,
Install looks good. If you wanted to hide the patchwork on the black carbon boards you can get some Rustoleum black spray enamel and lightly paint it. Wait a day and then wet sand. It blends it right in. I've done a lot of black carbon repairs. Just finished a retro fit on a 2016 Blackish and had to move the ventral box for the owner back toward the balance point about 12".
The White boards make it very easy to hide the repairs and fin box installs. This one I will paint once I test ride the board and make sure it worked for the owner.
Alright Barton is in the House. Nice work!
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UK, I suspect you're right about the refresh for SpeedCoach being triggered by stroke. Makes sense for what it's made for. I didn't think of tagging fin changes by distance. Duh.
I'm heading out to test another 4 fins in the morning while I still have something left of summer to play with.
(Trawling through the data I have so far, I'm pleased that on my second attempt of playing with test methodologies, not only have I managed to get great data repeatability, I also (and Area 10 will appreciate this) managed to obtain statistical significance between some fin performances too. I have completely misjudged fin potency and importance)
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(Trawling through the data I have so far, I'm pleased that on my second attempt of playing with test methodologies, not only have I managed to get great data repeatability, I also (and Area 10 will appreciate this) managed to obtain statistical significance between some fin performances too. I have completely misjudged fin potency and importance)
Apparently I have too. Are you testing three-fin setups?
I found another monkeywrench yesterday, or rather, confirmed (sort of) another factor I found but kind of ignored. Paddle choice is a factor in fin performance. 84 Konihi vs. 90 Mana somewhat reverses results. With the Mana 90, the stock center fin is faster than the little ventral fin in the center position. With the 84 Konihi the little ventral fin is faster. About a two percent difference. 84 Konihi with ventral is a little faster than 90 Mana with stock fin, about a one percent difference. I did only one short run with each, so the numbers are approximate and suspect.
I'm very tempted to paint that pretty carbon fiber bottom a basic white. I don't dare leave the thing in the sun for ten seconds. I'm considering adding another center fin box ahead of the stock position. I think I might be able to make this thing steer on a downwinder if I do. One more modification and I'm just gonna paint the thing. It will look like a frankenboard anyway. What do you think of a forward fin position with your cutaway fin Larry?
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Hey Bill,
you almost need a table of definitions of the fins and an Excel spreadsheet with the combination and results.
So your latest results look like:
Larger surface blade => larger surface central/kick fin
Smaller surface blade => Smaller surface central/kick fin
My fins and boxes should be arriving hopefully this week and I should have the board retrofitted the first week of October. I can then test with both the Mana 82 and Mana 90 (same blade shape, different surface) but I will need to borrow a small kick fin from the friend I sold my previous board to. Curious to see if this also apply to a weaker and lighter paddler.
Cheers,
Luc
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(Trawling through the data I have so far, I'm pleased that on my second attempt of playing with test methodologies, not only have I managed to get great data repeatability, I also (and Area 10 will appreciate this) managed to obtain statistical significance between some fin performances too. I have completely misjudged fin potency and importance)
Apparently I have too. Are you testing three-fin setups?
I found another monkeywrench yesterday, or rather, confirmed (sort of) another factor I found but kind of ignored. Paddle choice is a factor in fin performance. 84 Konihi vs. 90 Mana somewhat reverses results. With the Mana 90, the stock center fin is faster than the little ventral fin in the center position. With the 84 Konihi the little ventral fin is faster. About a two percent difference. 84 Konihi with ventral is a little faster than 90 Mana with stock fin, about a one percent difference. I did only one short run with each, so the numbers are approximate and suspect.
I'm very tempted to paint that pretty carbon fiber bottom a basic white. I don't dare leave the thing in the sun for ten seconds. I'm considering adding another center fin box ahead of the stock position. I think I might be able to make this thing steer on a downwinder if I do. One more modification and I'm just gonna paint the thing. It will look like a frankenboard anyway. What do you think of a forward fin position with your cutaway fin Larry?
Bill, Try the Dolphin Single fin I sent you and the Cutaway, moved forward in your board before adding a box. Or if you are not happy I will get you a Aercor for downwinding. Mahalo
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I raced this past Sunday in the Beyond the Shore Paddlefest inRedondo Beach. The 2 mile "Fun Race" started at 10:45am which meant the wind and swell was kicking up. The race was a simple one mile paddle straight out of King Harbor, a turn at the buoy, and one mile back into the harbor. By late morning the swells were hitting us from both the north and south. In addition, there was swells bouncing back from the break wall behind us. The fun race turned out to be quite a work out.
I had the Allison 4 fin set up on my Blackfish, but chose to use a larger medium ventral fin for stability. My observation for this tread is that not only was stability good, but I was able to paddle in a relatively straight line (tracking) and not be pushed left and right by the ocean. Much of my energy was devoted to paddling rather than keeping my board straight. No need for excessive paddling on one side to keep my heading.
In reviewing my Gopro pics, I noticed paddlers behind me would consistently show up to my left and then to my right. Wasn't looking for this, but seems like a confirmation that I was tracking true. Overall, it was a very satisfying experience. By the way, I was the oldest paddler of 50 racers!
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I raced this past Sunday in the Beyond the Shore Paddlefest inRedondo Beach. The 2 mile "Fun Race" started at 10:45am which meant the wind and swell was kicking up. The race was a simple one mile paddle straight out of King Harbor, a turn at the buoy, and one mile back into the harbor. By late morning the swells were hitting us from both the north and south. In addition, there was swells bouncing back from the break wall behind us. The fun race turned out to be quite a work out.
I had the Allison 4 fin set up on my Blackfish, but chose to use a larger medium ventral fin for stability. My observation for this tread is that not only was stability good, but I was able to paddle in a relatively straight line (tracking) and not be pushed left and right by the ocean. Much of my energy was devoted to paddling rather than keeping my board straight. No need for excessive paddling on one side to keep my heading.
In reviewing my Gopro pics, I noticed paddlers behind me would consistently show up to my left and then to my right. Wasn't looking for this, but seems like a confirmation that I was tracking true. Overall, it was a very satisfying experience. By the way, I was the oldest paddler of 50 racers!
Don't forget Brodog you took a first along with 17th over all against some pretty good paddlers half your age.Probably higher if the guy didnt ram you sideways at the turn throwing you in the water a mile out.
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Hahaha…Good times ProBox!!! ;D ;D ;D
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BroDog, Old guys doin' stuff! Huge ups dawg!!
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Hey Bill,
you almost need a table of definitions of the fins and an Excel spreadsheet with the combination and results.
So your latest results look like:
Larger surface blade => larger surface central/kick fin
Smaller surface blade => Smaller surface central/kick fin
My fins and boxes should be arriving hopefully this week and I should have the board retrofitted the first week of October. I can then test with both the Mana 82 and Mana 90 (same blade shape, different surface) but I will need to borrow a small kick fin from the friend I sold my previous board to. Curious to see if this also apply to a weaker and lighter paddler.
Cheers,
Luc
Actually I think it's more a matter of the catch differences in the Mana vs Konihi, though at this point any explanation will work for me. For me, the Mana catches big right away, and then softens up a little as I pull it. The Konihi catches softer, but pulls hard all the way to the end of the stroke. the Konihi also pulls straighter, no draws allowed, it just won't do it, and I have to push the Konihi deep--good for the Puakea stroke--or it gurgles.
If I was going to theorize, it would be that the Mana, catching way out front, is torquing the board more, and needs the bigger kick fin. The Konihi pulls steady and straight so it doesn't torques as much. At least that's my story for this afternoon. I think I'm learning a lot, I'm just not sure what.
Fortunately I just stumbled on a cache of two Larry Allison ventral fins that I have for my Speedboard. One bigger than the one I have, and one smaller. They aren't the click-in fins, they have a normal fin screw, but they'll be great for further testing. I'd go out now but the wind is up a bit.
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Hey Bill,
you almost need a table of definitions of the fins and an Excel spreadsheet with the combination and results.
So your latest results look like:
Larger surface blade => larger surface central/kick fin
Smaller surface blade => Smaller surface central/kick fin
My fins and boxes should be arriving hopefully this week and I should have the board retrofitted the first week of October. I can then test with both the Mana 82 and Mana 90 (same blade shape, different surface) but I will need to borrow a small kick fin from the friend I sold my previous board to. Curious to see if this also apply to a weaker and lighter paddler.
Cheers,
Luc
If I was going to theorize, it would be that the Mana, catching way out front, is torquing the board more, and needs the bigger kick fin. The Konihi pulls steady and straight so it doesn't torques as much. At least that's my story for this afternoon. I think I'm learning a lot, I'm just not sure what.
YEAH BILL, You are Not Theorizing, You are EXACTLY right now you are talking Sup fin Language. Right ONNNNNNNNNNNN!!!!!!!!!!!!
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Actually I think it's more a matter of the catch differences in the Mana vs Konihi, though at this point any explanation will work for me. For me, the Mana catches big right away, and then softens up a little as I pull it. The Konihi catches softer, but pulls hard all the way to the end of the stroke. the Konihi also pulls straighter, no draws allowed, it just won't do it, and I have to push the Konihi deep--good for the Puakea stroke--or it gurgles.If I was going to theorize, it would be that the Mana, catching way out front, is torquing the board more, and needs the bigger kick fin. The Konihi pulls steady and straight so it doesn't torques as much. At least that's my story for this afternoon. I think I'm learning a lot, I'm just not sure what.
Fortunately I just stumbled on a cache of two Larry Allison ventral fins that I have for my Speedboard. One bigger than the one I have, and one smaller. They aren't the click-in fins, they have a normal fin screw, but they'll be great for further testing. I'd go out now but the wind is up a bit.
Works for me. After paddling exclusively the Konihi 84 for a season, I still bury the Mana just like the Konihi...
Cool that you have now all three sizes of ventral which might end-up kick fins actually.
Cheers,
Luc
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Nice to see the other side of the world follows me and understands Allison multiple fin combos like this that popped up on my facebook this morning.
Quote from facebook:
Sup Race Fins
31 mins · Edited ·
CROSSWATER Running Allison Ventral Fin combo in Sweden
Like This Page
Henrik Friberg shared a photo to your Timeline.
1 hr ·
Waveriding a 12'6" raceboard with a ventral here in Sweden works great. Probably works great in the rest of the world too :)
Ulrik Kursten med ventralfena.
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That is a pretty awesome shot!
Larry, has anyone done a ventral fin using a ProBox instead of a traditional single fin box? Does the ventral fin-tab need to be longer than a ProBox?
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New wallpaper!! 8)
Will
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That is a pretty awesome shot!
Larry, has anyone done a ventral fin using a ProBox instead of a traditional single fin box? Does the ventral fin-tab need to be longer than a ProBox?
Yes Bean Thomas Max of Future tried using this set up for a Ventral which failed the performance test and they stopped in 2012. The base on my small Ventral is 7 inches long. You could use a Probox but the lateral torque will give you less lateral resistance and the foil section of the Probox verison would be to thin which also plays a role in performance of the Allison Ventral.
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Be ready Larry....I'm going to ask Patrick to talk to you about fin placement on my new unlimited......you guys will be talking for hours. I'm getting cauliflower ear just thinking about it..... :) 8)
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That is a pretty awesome shot!
Larry, has anyone done a ventral fin using a ProBox instead of a traditional single fin box? Does the ventral fin-tab need to be longer than a ProBox?
Yes Bean Thomas Max of Future tried using this set up for a Ventral which failed the performance test and they stopped in 2012. The base on my small Ventral is 7 inches long. You could use a Probox but the lateral torque will give you less lateral resistance and the foil section of the Probox verison would be to thin which also plays a role in performance of the Allison Ventral.
Rats! I suppose a carbon fiber fin would be too stiff...but what about a hybrid CF fin tab and base with a FG blade?
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More pics show up from PPG showing Ventral and Allison Probox Twins in the Elite Race. Kristin Thomas for Infinity here in these pics.
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I did find that pounding my ventral fin into the cobble on my clumsy PPG dismount didn't do the fin box much good--it sprung a leak even though I glassed under it. I guess that's a bit too much to ask of an ounce of carbon and glass.
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I did find that pounding my ventral fin into the cobble on my clumsy PPG dismount didn't do the fin box much good--it sprung a leak even though I glassed under it. I guess that's a bit too much to ask of an ounce of carbon and glass.
Ponobill, You are lucky with a leak my friend. Because some of the boards I seen that hit the beach were done period. Great seeing you on the party video Dave Boehne was doing for Supthemag. , but missed you at the beach. Got to give you thumbs up for doing that event conditions were crazy.
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Larry W. Allison
16 mins ·
View on Instagram
Glad to see after this last weekend at Pacific Paddle Games people are realizing and understanding the need of having a Allison Ventral assist added to their 3 fin combo. Super excited to see major board companies like @infinity_sup leading the charge using Allison 4 Fin Race Combo and now Starboard in Testing mode. Super excited to see companies in 2017 moving into the next level of evolution in the Sup world using Allison Probox 4 Fin Race combos. Think super hard when buying your next board, that it comes with the Allison Race Combo to give you all the options to enjoy your paddleboarding experience. Tell them Larry sent you.#twinstowin,#sup,#suprace,#supracefins,#paddleboarding,#standuppaddle
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No, I didn't plug it. The side fins are toed a little, according to my laser the intersection point of the toe is about six feet in front of the nose of the board (about 19' total), so pretty small. I'd convert to degrees, but who cares other than my old trigonometry teacher, who is probably safely dead.
I'm finding this very odd. I think your explanation might be on the money DW, which leads me to wonder how small the fin can be and still get the same result. I'm pretty certain that bigger fins are slower for me (stronger paddlers might not have the same result), but will smaller be faster. I think all the work of making the board track and resisting the torque is being done by the nubs, and the middle fin might just be a flow straightener.
I'm just guessing, but it opens some interesting options. Larry is definitely onto something.
UK, I suspect you're right about the refresh for SpeedCoach being triggered by stroke. Makes sense for what it's made for. I didn't think of tagging fin changes by distance. Duh.
Any updates on this Bill ?
I'm waiting for calm weather to do my usual scientific testing but i've now had a 4 fin set up in the water for a couple of weeks with mixed impressions so far. I'm certainly not sure either way yet based on how it feels so far. I've now got a smaller ventral on order to stick between my two twins to see how that feels on flatwater.
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Nothing in any way scientific, just a lot of impressions. I'm currently (currently being two months ago) using two small Larry fins that I made even smaller--the trapezoidal ones that came with the board. They are now 3.5 inches long and 1.5 inches tall. I have a .040" aluminum fence with the edges sanded round between them that is 4 inches long and two inches tall, pushed all the way back in the middle slot. And my smallest ventral fin--I don't remember what that is. This is the fastest setup I've found for flatwater. It's fine for chop and even upwind too, though if the nose gets too far across the wind it's a challenge to get it pointed back upwind.
This setup is more than 10 percent faster than a big single fin with my limited testing. I'm sure that number isn't real, but it's a big enough change to be interesting even without disciplined tests.
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They are now 3.5 inches long and 1.5 inches tall.
Whoa, that small.
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This setup is more than 10 percent faster than a big single fin with my limited testing. I'm sure that number isn't real, but it's a big enough change to be interesting even without disciplined tests.
Cripes ! Even half that would be impressive.
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They are now 3.5 inches long and 1.5 inches tall.
Whoa, that small.
I'm amazed any surface turbulence isn't large enough to overcome them and therefore not allow them to function properly and would make the board slide around. That's great work though Bill. I'm still bedding in with mine but I do wonder if the concept isn't so effective on a deep triple concave board like the '17 allstar.
I'm still at the 'replace the kick fin for a ventral' phase......
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They are now 3.5 inches long and 1.5 inches tall...
Are you sure about those measurements? my tail would drift like a puppy happy to see its owner
after a year long vaca. Your board must be sitting so low you could probably run with just a groove
in the back :)
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Me fat, you not. Brain fart though. 5.5 inches long, 1.5 inches high. I took the 9" X 4.5" trapezoidal Larry fin and drew a line from the end of the front overhang parallel to the original edge, then drew a line parallel to the upper edge the same width as the first line. Cut them on my bandsaw and foiled them with an angle grinder. The idea was to not take small steps--do a big jump and see what happens. When I looked at them I thought "shit--overdid it. these are way too small." But they work fine and track well. Things get very touchy if I pull the ventral fin, but with that in place it goes very well.