With all the different bottom designs floating around out there..from flat to single to double, to triple concaves, the Starboard tunnels, V bottoms, convex bottoms and all the varieties which combine these...what bottom shape have you personally found to be both stable and slippery in a 26" X 14' race type board.
The board that made you say out loud....Wow! This thing feels like a hot knife through butter. That goes well in chop upwind, wind on the beam, downwind. What did you attributes do you feel made it paddle so well?
Parameters:
1) Not a "Rat on Acid" pace that the top 2% perform at getting their board to practically plane...
2) Relativly flat water (Intacoastal) with chop, and East Coast of Florida (not Hawaiian) open ocean swells.
3) In the neighborhood of 26" wide.
4) Paddles well into the wind (realitively speaking)
Looking for specifics, not general statements like "nice rockerline"...how much rocker? Was it near flat for 75% of the board with 1" nose kick and 4" of tail kick? If so where was the break? Have sharp rails, soft rails what was the radius? Etc.
I developed some very effective rocker lines for windsurf boards in the past, tried most of the options available, even phasers, but SUP is a completely different animal.
My last 14 build, while it works well, didn't give me as great a boost in speed over my 12'-6" as I anticipated. Maybe my expectations were too high. I am a bit faster over all, but I don 't have the ability to dig in and really get the 14 moving in a sprint like my 12-6". My 12-6 really rewards the effort and takes off. The bottom shape is along the same shape single concave to V on both boards.
I was anticipating noticeably less resistance from a board 1-1/2' longer, 3-1/4"narrower with a much finer entry. The way the nose parts the water is glorious, yet there is a feeling of drag to me that shouldn't be. The board is under finned (7" Fins Unlimited longboard classic shape) and I am sure a slightly larger/better foiled fin would help...how much I'm not certain. I have a new foam core fin under construction. The design is halfway in-between a VMG 37 and VMG TT.
This is more for fitness than anything... but I'm getting board looking at the same 9 miles down and 9 miles back...over and over again...want to cover more ground in the same amount of time...and the less resistance I'm fighting against, the better.
Things on the forefront to change...
More tail rocker (1-1/2"-2") in the last 42" (marginal at the moment on the 14') to get better tail release so I can move back on the board and still have a good clean minimum wake. Take 1" of nose rocker out of the first 18" so I can engage the wave piercing nose sooner, and from father back on the board.
Fill out the hips in the out line slightly.
Pull in the square tail width 1"-1-1/2".
Take 1"-1-1/4" thickness/volume out of the board throughout. Way more volume than I need at 150-160 lbs. Should help in weathercocking in wind on the beam.
A little more rail tuck but still keep a hard edge for clean release. Lowering the center of gravity should help compensate for increasing tuck in rails (effectively compensate for loss of stability due to reduced bottom width).
If I stay with single concave, deeper concaves closer to the nose to introduce more air under the bottom when standing forward (going up wind), as it transitions from V/double concave the first 2 feet to single concave.
I am more inclined to go with a double concave from nose to tail to help with straight tracking and reduce strokes per side (single concave seems to work against this).
If it were not for the enhanced tracking aspect of the double concave, I would be tempted to go with a simple flat bottom with a slight V in the tail...it sure worked great for windsurfing. Less is sometimes more.
After trying a dozen or more bottom configurations with my windsurf boards, the fastest ones inevitably ended up having dead flat bottoms with slight V in the tail.
Please share your experiences. What was The magic board for you? What made it so? Always looking to take it to the next level. Always more to learn. The more detail the better. Thanks to all that participate....
Quote from: SUPflorida
After trying a dozen or more bottom configurations with my windsurf boards, the fastest ones inevitably ended up having dead flat bottoms with slight V in the tail.
Yep. You got it.
It's horses for courses. Dead flat bottom will give you the minimum form drag for the profile of the board you build. But it won't track very well and you might waste energy and effort keeping it on line and switching the paddle excessively. You'll also probably wind up with a lot of fin.
Any shape that directs the water a bit will track better, that's why concave bottoms are attractive, and tunnel hulls with chines can almost do away with a fin. But they're draggy. You also don't want water rolling up over the rails.
That said I haven't found a magic hull, but I've found some really slow ones.
definitely, partly rounded bottoms. sorry for translation,look here:
http://paddlespot.net/download/les_carenes_de_SUP_race.pdf
but also some pics here: http://www.forumdesup.com/t11154p30-pierrotboards-4-et-5#115117
andin that facebook page:
https://m.facebook.com/Hi.fun.hydroworks/?ref=bookmarks
the board shaped by Dave for Jean_Marie here
https://m.facebook.com/photo.php?fbid=10202428602252046&id=1103446562&set=t.701692111&source=42
best glide performance on flat and light DW donditions.
Pierre ... Is that available in English?
No shape details, but I've owned/paddled double concave (original JL Blade), single concave ( SB Sprint), and convex (SIC X-14 ProLite) and prefer convex based on these off the shelf examples.
I agree, for flatwater a rounded bottom is the fastest as long as you can handle the roll.
At planing speeds, a flat bottom with V in the tail works great, but on flatwater you will be at sub-planing speeds and a rounded bottom with rounded rails is the most slippery in my experience.
http://blueplanetsurf.com/blogs/news/48809349-the-fastest-race-sup-displacement-vs-planing-hulls-board-weights
Quote from: SUPflorida on January 19, 2016, 05:57:43 AM
Pierre ... Is that available in English?
Sorry, not yet, I work on it at times...but still need to translate 100 page, I will prepare an english short version :)
Quote from: blueplanetsurf on January 19, 2016, 09:01:20 AM
I agree, for flatwater a rounded bottom is the fastest as long as you can handle the roll.
At planing speeds, a flat bottom with V in the tail works great, but on flatwater you will be at sub-planing speeds and a rounded bottom with rounded rails is the most slippery in my experience.
http://blueplanetsurf.com/blogs/news/48809349-the-fastest-race-sup-displacement-vs-planing-hulls-board-weights
....sure, because a planing hull is useless on a UL in flat or light DW condition as we never reach those speeds, and anyway works perfect in semi_planing conditions where it slowly accelerates but does not "stick" on water, means keeps better inertia.,however, I succeded fantastic glides including boat wake riding on mines. drive is just a bit special.
Quote from: SUPflorida on January 18, 2016, 12:23:54 PM
The board that made you say out loud....Wow! This thing feels like a hot knife through butter. That goes well in chop upwind, wind on the beam, downwind. What did you attributes do you feel made it paddle so well?
Hi guys
We all know that surfskis (rounded bottoms) a really fast, so SUPs with partly rounded bottoms should be the answer, if you find the good compromise between speed and roll. This compromise depends a lot on the paddler's height, weight, and of course skill. Pierre is really good at finding this compromise.
I already built three 14' boards, based on Pierre's designs.
The 1st one (and my home made board), 14' x 29", august 2014, was just a draft. Too wide, quickly built, too heavy, but really impressive. Maybe not the fastest board ever, but definitely slippery and effortless at speeds around 7 km/h (4.5 mph)
(https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-xap1/v/t1.0-9/10405410_275061019371091_5135965481720855843_n.jpg?oh=b8f70052142158f3b27ac6e0de90bee8&oe=5701BC31&__gda__=1463774957_8802abd487b5e59c4d2d3f1b22c88d5b)
(here on the left, compared with a 2012 Naish Glide 12'6)
And really stable
(https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xft1/v/t1.0-9/10672217_287528544791005_7652720417658473282_n.jpg?oh=ef582308df55c8be7053bea4777618ba&oe=5732D55D&__gda__=1463287511_d28cee53137699b582607818fa448b95)
February 2015 : The 2nd one, 14' x 26". Flatwater version of #1. Really fast, but a terrible roller, my favorite on lakes and rivers but I won't go out to sea with this one.
(https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xft1/t31.0-8/11823089_415453091998549_1160522311689602545_o.jpg)
(https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-xat1/t31.0-8/12017617_415868601956998_7417774728064105563_o.jpg)
#1 and #2 (above)
(https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xta1/v/t1.0-9/10391021_415453075331884_2295755356751333667_n.jpg?oh=3cb7b952db707a31b7fea17271b0cc1f&oe=574214C7&__gda__=1464343886_06f782d121663ff9faa565ff24bf8593)
More than 60 km (39 miles) in 8:32, I was not really tired, I could have paddled a few hours more.
(https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-xat1/t31.0-8/12002539_415869121956946_1257157564130929514_o.jpg)
Testing #1 and #2, debriefing with Pierre
#3, just lauched. The qualities of #2, with just the little more stability I needed
(https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-xfl1/v/t1.0-9/12373174_444206449123213_1579749321020988099_n.jpg?oh=0233dded01409f27d9df81b00215c86b&oe=574390AF&__gda__=1459393197_32a7271afe70c81bb82390dcfa376409)
(https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xpt1/v/t1.0-9/12552613_449822531894938_7062249383703096220_n.jpg?oh=b88ff21143be91f374b1db06683a08ef&oe=57384D56&__gda__=1464427858_07944640137d561179f2fa957ba5e4e6)
If you have minimal tail rocker on the first 14 then I think that is your major thing to change. On my first 14 I was very careful to figure out volume and displacement so that the tail would be releasing exactly at the surface for my weight. But that was all based on standing still and just floating. In reality, with the dynamic lift from the water, the board pitches up and sinks the tail in a bit more. I added more tail rocker in board #2 so the tail sits out a bit when stopped, and it feels faster. It's tough to know what rocker you need, because the volume below the water depends on the rocker curvature, as well as how wide your board is throughout, and not just the maximum width.
I think rocker is going to be much more important than changing from a flat bottom to a subtle concave type shape. Also, while rounded bottom is theoretically faster, the balance thing is a draw-back, and can slow you or require more overall width. I think there are mostly-flat and rounded bottom boards out there that are both fast. Are there any fast flatwater type boards with minimal tail rocker? I doubt it, so that has to be the big improvement, I would think.
Peter
I haven't done 14 footers in at least 5 years, so I'm not up to date, but here are the few bits I learned shaping them.
- The narrowest board was the fastest. I kept adding tail width to allow me to stand on narrower boards. My last board was darn near parallel in template and my fastest board.
- I tested progressive rocker versus constant curve. Progressive paddled faster, but felt speed limited compared to constant curve. I was building boards for down winding, so mine did plane up. For something that will never plane up, I'd go progressive curve.
- Even though everyone knows displacement is the fastest paddling hull, I never considered it due to stability issues. Flat was as close to displacement as I wanted to go.
- Deep fins are slowest, so I'd follow Larry Allison's development path and go short multi-fin. Larry is doing a mid ship fin. It might be what a flat bottom needs to fly straight.
Quote from: DW on January 20, 2016, 04:53:21 AM
Flat was as close to displacement as I wanted to go.
- Deep fins are slowest, so I'd follow Larry Allison's development path and go short multi-fin. Larry is doing a mid ship fin. It might be what a flat bottom needs to fly straight.
Good info. I am planning on modifying a board to add multi-fins.
Cheers,
Luc
Quote from: DW on January 20, 2016, 04:53:21 AM
- Deep fins are slowest, so I'd follow Larry Allison's development path and go short multi-fin. Larry is doing a mid ship fin. It might be what a flat bottom needs to fly straight.
My feeling is that off the shelf fins are awfully thick, 10 to 12 mm (1/2 inch) , heavy and expensive. I build my own fins using 4mm plywood+one layer of carbon fiber, thickness around 5mm (0.13⁄64in), super light, minimum drag.
(http://i21.servimg.com/u/f21/18/23/49/00/captur29.jpg)
Thank you all so much...while experiences seem to cover the spectrum from one end to the other, there are good bits to gleam.
I've also been digging into a lot of video and interviews with board designers. I like Mark R. a lot (SIC). He seems like "what you see is what you get" kinda guy. He shares a lot of good info in his interviews....his approach...what he finds is most critical ...and something I really find valuable...what sounds really good, but doesn't prove out on the water. And while he is world renown as the King of Down Wind ...he's no "one trick pony"
You guy are really helping me focus in. I have come to several conclusions since starting this post.
1) I really like a lot of things about my current board and I have to agree with DW on the round bottom. I have yet to get wet on my 26"'wide 14' but I'm pretty confident I would not be able to say that if I rounded the chines to what Paddlespot has. My water very seldom looks as flat and wind free as his pictures.
2)DW I also like my wide tail for stability but now I'm thinking that is the reason for the need for more tail rocker in the last 18". I am seeing two approaches one is straighter centerline rocker with narrow (pintailish) tail or a realitively exaggerated tail rocker with wide tail. Both achieve a level of clean water release but by different methods.
Peter
My current boards tail sits approx 1-1/2" clear of the water at rest with no rider. Maybe 3" nose rocker (no rider).
As I move forward to achieve better tail release, I start moving away from the wide point and the board gives up that rock solid stability it has when standing 10"-12" further back. I believe the overall rocker is almost dead on but needs to be re-distributed. Hence The reason I should lower the nose rocker equal to what I raise the tail rocker.
This would effect multiple things:
A) Lower the nose to bring the wave piecing effect sooner. The current nose cuts super clean with no rail wrap.
B) Give Cleaner tail release.
C) Allowing me to stand farther back on the board for better alignment with the wide point to enhance stability.
D) Which could allow me to drop another inch or two of overall width.
So now the question is to go to a double concave for tracking or not? Nothing crazy...say 1/4" per panel. Extremes always seem to work against you. Water likes gentle changes she moving at slow speeds. One thing I will do is start the concave all the way at the nose...the transition from flat to concave although a staple in surfboard design...doesn't seem to work all that great in flat water at least when one has to move forward to release the tail and use the full waterline length.
My hypothesis is this & the need to raise tail is where my resistance is originating.
My conclusion so far:
Refine & build on what I have now rather than heading in an entirely new direction and starting over from square one.
Redistribute current rocker, drop nose, raise tail.
DW
While I acknowledge the mid-ship fin is one answer to enhanced tracking... I still have doubts if it's the best solution when approaching a new build. I totally get it when trying to "fix" an issue with an existing board, but I would rather change a bottom contour and achieve the same thing if possible. But as you said that could be a simpler solution in the long run...save a lot of work trying to get all the concaves to blend right without causing wierd unpredictable turbulence. Have to give that more thought....
For those with double concave Naish Javelins...does the double concave have a noticeable effect on tracking? Or not?
Quote from: DW on January 20, 2016, 04:53:21 AM
...
- Deep fins are slowest
...
You mean it is more about depth than surface area?
Any idea why this is?
Water density .. re deep fins being slower..
and re the Naish Jav's double concaves effecting tracking.. IMO it should but how would you know?.. There's so many things in a board shape that effect tracking.. They are also there for other reasons than just tracking..
DJ said..."and re the Naish Jav's double concaves effecting tracking.. IMO it should but how would you know?.. There's so many things in a board shape that effect tracking.. They are also there for other reasons than just tracking."
I agree, but would you care to expand on that thought? My overall outline (granted just one small part of the equation) is very similar to a 26" x 14' Javelin.
As one who has owned or ridden pretty much every Naish race board in the last 5 years (?) I would be very interested to hear your impressions of the evolution of the various bottom/rail/rocker designs over the years compared to its current offerings.
When you think about it...many of the bottom designs under discussion have been tried on race boards by Naish. It seems to be a slow but constant move away from the more traditional rounded hull designs...at the same time user comments are made of steadily increasing stability with each itineration. all the while the boards overall width gets narrower, tails wider, rocker lowered, rails harder.
Quote from: SUPflorida on January 20, 2016, 10:25:26 AM
DJ said..."and re the Naish Jav's double concaves effecting tracking.. IMO it should but how would you know?.. There's so many things in a board shape that effect tracking.. They are also there for other reasons than just tracking."
I agree, but would you care to expand on that thought? My overall outline (granted just one small part of the equation) is very similar to a 26" x 14' Javelin.
As one who has owned or ridden pretty much every Naish race board in the last 5 years (?) I would be very interested to hear your impressions of the evolution of the various bottom/rail/rocker designs over the years compared to its current offerings.
When you think about it...many of the bottom designs under discussion have been tried on race boards by Naish. It seems to be a slow but constant move away from the more traditional rounded hull designs...at the same time user comments are made of steadily increasing stability with each itineration. all the while the boards overall width gets narrower, tails wider, rocker lowered, rails harder.
IMO as far as Naish DW boards go I think the rails have actually got a bit softer.. and the noses have got a bit wider.. and the rocker is where the biggest changes are.. I much prefer concaves in the bottom rather than flat.. You can feel the air they trap unsticking the board from the water.. I'm thinking the wider noses has more to do with the added stability in the newer boards.. But the is key.. You want the most suttle entry curve/rocker.. Both to stop pushing water and allow use of the total waterline.. and I'm thinking they have brought the start of the tail rocker slightly forward to allow you to get back to lift the nose when needed without needing to get too far back and bog the board down.. I'd like to see a bigger and deeper rail that goes further back like what the Allstars have.. I like the Maliko nose but I'm thinking something between the Maliko and normal Jav might be best because it's the volume that brings a nose back up after pearling rather than just the nose rocker.. I think if you're going with an Ace like nose you need a narrow tail like what Fanatic are doing.. Because when the nose goes up the tail needs to go down.. Personally I'd rather pierce than boof but boofing might end up being the way to go.. It's still early days in these boards.. Particularly DW boards.. I'm looking forward to see what Naish comes up with next.
(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5956_zpshd10twcy.jpg)
(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5954_zpspz5pvil1.jpg)
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(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5960_zps0hzzzofm.jpg)
(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5965_zpsiiq62chc.jpg)
(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5966_zpstcbfozeq.jpg)
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(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5967_zpshd9ttote.jpg)
(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5968_zps5rhi2gbh.jpg)
(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5979_zpscmg9tela.jpg)
(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5975_zpsu72hsgtj.jpg)
(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5977_zpstzynehnw.jpg)
(http://i774.photobucket.com/albums/yy27/djp-3/DJ%202012%20pics/IMG_5974_zps1lb2drmb.jpg)
DJ
Thank you for posting all those pictures. I have watched many of your video reviews before on these boards but the stills give a much better perspective than the go pro.
What jump out at me is:
1) Rails are softer with more tuck than I originally thought.
2) There is not a crisp well defined centerline on the double concave the complete length of the board. Fairly crisp at nose but rounded considerably as you moved back...no close up tail shot...does it keep the subtle rounding? go back to a chrisper V? Or run out flat?
3) The concave under (what looks like) the standing area, while still technically a double concave....has the centerline deeper than the rail line forming essentially a single concave effect.
One of my windsurf slalom board designs has a double concave where the centerline was even with the rail line...it would accelerate and go up wind like nothing else...the down side was a decent top speed but it would only go so fast and hit a wall. That of course is not an issue for SUP as an SUP would never get to that speed in the first place. Might be a good application for lower speed craft.
I totally agree with your rocker comments, notice several of the latest and greatest with the rocker break positioned right behind the main standing area. Allows easy access to raising the nose without having to move as far back to execute. That's something I learned about building waveski's, with those you are planted in one place. Waveski's Rocker break is hypercritical as you can only shift weight by moving your upper body.
Reading again initial post, I suggest another solutionof bottom shape with semi_rounded bottom and slight concave inside rail edge, and quite rounded rails, more rounded bottom section near to nose. i suggest abt 2 " nose rocker and progressive 2" tail rocker for a piering nose, this nose rocker to be increased to 3" in case of wide nose.(for more choppy condition, non piercing nose) Idea is to allow more lift under the rails, keeping advantage of a rounded bittom for clean water entry at nose. water exit to be slight V section.
Pierre
Good stuff...Your description seems to line up with the Naish Maliko which seems to be doing very well. That's quite a step away from where I am right now which would be closer to a slightly less extreme nose profiled Javelin.
Can't imagine giving up the clean entry I have now for the broad nose Maliko or the boof style nose.
The more I picture the nose of my current board cutting through the water, the less I want to touch that part of the board...other than lowering the rocker in the front 18". Funny if I had kept with my original rocker hot wire template I would be right where I needed to be...or at least closer...but at the last minute I cut in about an 1" more rocker in the front 18". Even with the added 1" of rocker my rocker entry is very subtle.
My rails are just short of knife hard (1/8-3/16 radius) and there is zero turbulence, no bubbles, no splashing at all going on ...none of the sprinkler effect I see in videos of other boards...zero rail wrap...this part of the board is near perfect going through the water. Especially when the bottom tip of the nose is even with the water line. If I can get the rest of the board to that level of performance I would be a very happy camper.
As DJ was saying about the concaves trapping air...that's what I have experienced with them before on surfboards/sailboards/waveski's. Using rounded rails and bottom features to accomplish this seems a little counter intuitive to me, want the air to remain trapped under the board and exit the tail...hopefully supplying at least a minuscule amount of lift. I have always gone with much harder rails on all my surf/water craft than has been the norm...it just always worked better for me personally.
Something in my single concave bottom is just not tweaked right. There is some funky turbulence going on. I say that because when you look at how effortlessly the nose of the board parts/skims on the water you would think the whole board should feel as resistance free as an "air hockey puck". Also when going down breeze every so often the suction breaks loose and the board takes off so fast it wants to throw you right off the back. Don't get me wrong my current board is no dog but it is screaming to me that there is a lot of untapped potential very close to be captured.
As I said before, maybe the concave needs to start farther forward to inject more air under the board sooner? Maybe instead of transitioning to flat V panels in the tail it should maintain at least a subtle double concave all the way through the tail? Thoughts on how to alivate suction on concave bottoms? Already planning the obvious....more tail kick..I'm all ears on what you have experienced.
If the weather cooperates this weekend (not too likely as it is suppose to blow like stink) I want to find some really flat water and use my phone to video how the boards moves through the water at various standing positions. See how much of shift in rocker ( take away from nose/add to tail) I really need without swinging the pendulum too far in the other direction.
This discussion is really helping...in addition to all your great insights, there are many things I experimented with years ago and have forgotten....you guys are reawakening them as well....I appreciate it all!!!!
There is a really good explanation of the bottom shape of the 2016 AllStar in this video, they reveal the "secret sauce" of the board.
https://www.supboardermag.com/2016/01/18/sup-review-2016-starboard-all-star-all-round-race-sup/
TN_SUP
Thanks for posting that 2016 SB Allstar Review.
That's certainly a unique amalgamation of approaches to achieve their goal. Beautiful board and appears to check all the boxes the designer was going for.
Interesting points on their application of concaves. Trying to think of a way to apply the design attributes of the Allstar highlighted in the video to my issues..
That sprinkler effect at the nose of the board is not necessarily a bad thing. IMO at cursing speed it's good to have a piercing nose cutting through the water, but when you want to hammer it to reach maximum speed you want a nose that is designed to lift and break over what I think is the bow wake the board is creating. I may me wrong but that is what I feel is happening when the sprinklers turn on as my speed increases. My board has a piercing nose transitioning to a rounded bottom, to a double concave (2014 Allstar). Just want to add that you have to have good technique and be fit to take advantage of that design. Something I'm working on.
Chilly
I get where your coming from ...correct me if I'm wrong....but here is my logic... that sprinkler effect is pushing water and wrapping it up the rails...that water doesn't move by itself...some of your paddling effort is being used to move that water. Whatever energy expended generating the sprinkler effect is not moving you forward. Any wasted effort, regardless of its source is keeping you from attaining your personal best speed for a given amount of effort.
That is one reason why I'm "married" to the idea of keeping my existing nose design.
It too can easily lift free is you have the strength/skill/endurance to push it hard enough. A quick video check of Kie sprinting on a 2015-16 Javelin will demonstrate how well a piercing nose can "plane up" if you have the horsepower and enough gas in the tank.
There are multiple approaches to accomplish the same thing, so whatever flavor that gives you the best experience is the one right for you. Thank you for your comments.
I agree with your logic and I'm hesitant to comment on this subject because I know nothing about hydrodynamic. I'm just going by feel. My logic is that yes you're pushing water, but at the same time the board is lifting up off the water which causes less resistance. It's a tradeoff. If your nose design can easily lift than I wouldn't touch it. Personally I don't like pure displacement boards unless maybe on an unlimited because you have the advantage of board length (Hull Speed) and I would think it will take a massive effort to get it to semi plane.
I just picked up the latest 2016 Antoine Albeau race board (windsurfer). He's won the world title the last 4 years on these boards.
Apparently flat bottoms still dominate racing in 2016, for windsurfers.
(http://i238.photobucket.com/albums/ff242/fishersfort/IMG_1257%201_zpsujaxgosl.jpg)
^ yep. Concaves, lots of concaves, came and went in windsurf boards.
I really notice the pendulem swing in new sports and try to stick to the middle ground.
Thanks for posting that DW. I really like flat bottoms, they are fast, stable, create a lot of lift and are neutral when turning. The old C4 Waterman 14' Vortice XP boards had deep double concaves, which at the time seemed like a great idea but compared to modern downwind raceboards with flat bottoms or very subtle contours they are pretty awful. I would stay away from deep concaves and instead focus on getting the rocker line just right.
From DW > I tested progressive rocker versus constant curve.
Hi DW --- could you expand on this just a bit for my old slow mind --
I have used a constant curve from about center of the board or just a bit forward to the tail for that section of the rocker and the same concept for the nose -- am I right the "progressive" is more curve as the rocker approaches the nose and tail -- ?????
thanks for the post you all this is a great thread -
aloha
willi
Quote from: blueplanetsurf on January 28, 2016, 04:34:10 PM
Thanks for posting that DW. I really like flat bottoms, they are fast, stable, create a lot of lift and are neutral when turning. The old C4 Waterman 14' Vortice XP boards had deep double concaves, which at the time seemed like a great idea but compared to modern downwind raceboards with flat bottoms or very subtle contours they are pretty awful. I would stay away from deep concaves and instead focus on getting the rocker line just right.
I so agree on principle and seeing fads fail the tests of time. Yet I still am really intrigued by this years SB Allstar. Haven't heard a great deal of feedback other than so stable one can go a size narrower. Wondering how that's is working. When tipped is the rockered chine acting like a single rockered "hammock" like stable DW shape?
Sizing down is width is definitely faster and better for paddling so something is going on there.
In regards to the SB Allstar...is it their take on the Infinity Black Fish ST? or the other way around? Seems both boards have a lot in common...not exact, but both seem to have a rounded entry, to flat to a single concave that gets progressively deeper and extends all the way to the tail. They both have the chines outside the concave. SB took the attribute to a bit of an extreme...history has shown in the vast majority of cases, that that more subtle uses of these type bottom tweaks are more advantageous. I own neither brand so I don't have a dog in this fight.
Quote from: willi on February 01, 2016, 07:06:17 PM
From DW > I tested progressive rocker versus constant curve.
Hi DW --- could you expand on this just a bit for my old slow mind --
I have used a constant curve from about center of the board or just a bit forward to the tail for that section of the rocker and the same concept for the nose -- am I right the "progressive" is more curve as the rocker approaches the nose and tail -- ?????
thanks for the post you all this is a great thread -
aloha
willi
You are correct from my point of view. Just beware, when marketing people create their BS, use of the word progressive could mean, progressive design, cutting edge, etc and not what an engineer would mean.
Quote from: DW on January 20, 2016, 04:53:21 AM
I haven't done 14 footers in at least 5 years, so I'm not up to date, but here are the few bits I learned shaping them.
- The narrowest board was the fastest. I kept adding tail width to allow me to stand on narrower boards. My last board was darn near parallel in template and my fastest board.
- I tested progressive rocker versus constant curve. Progressive paddled faster, but felt speed limited compared to constant curve. I was building boards for down winding, so mine did plane up. For something that will never plane up, I'd go progressive curve.
- Even though everyone knows displacement is the fastest paddling hull, I never considered it due to stability issues. Flat was as close to displacement as I wanted to go.
- Deep fins are slowest, so I'd follow Larry Allison's development path and go short multi-fin. Larry is doing a mid ship fin. It might be what a flat bottom needs to fly straight.
DW ...how narrow did you go with your last 14 (overall width) and how wide was the tail?
I keep re-reading all the comments trying to keep an open my mind as to what's really being communicated.
26 wide. Tail width I don't recall. It was probably 5 years ago.
To sum up then, flat is fastest until you want to do something other than go straight in no wind.
FWIW, we called the old Vortice the Tortice.
^ excellent summary
Likewise my mid 80's Cobra radical 260 and 290 windsurf boards with major concaves were a dream to turn but ended up being way slow compared to other boards.