MyPaipoBoards Forums

A few photos of my latest board: 50" x 19.5" x 1 1/8".
I've ridden it in small hollow beachbreak and decent 4' point waves. Not as fast as my other boards but holds an edge and definitely fun. Despite the thinness it catches waves ok. More of a pocket board than my other boards but it's limits haven't been really tested. It is light at 2.2kg but very strong because of the build . The inspiration sources were OneHand clapping's board, Soulgliders, Krushers and drawings Paul Gross did for me. Huie from Swaylocks interpreted that pot pouri and after a few e-mails and phone calls you can see the end result.

Bob

Nice one there Bob. Just watched this vid of Maurice Cole, thought that long single concave looked interesting, then you posted yours.

http://www.korduroy.tv/shows/local-lege ... rice-cole/

Nels

Noice !
Have you ridden it without a rashvest or wettie ? Is the cork as grippy as wax or do you need wax as well ?
I'm thinking of incorporating cork into my builds.

Hope you are well, Brett.

Hello Nels,

I had another board made by Huie but the shape of the concave was different to Cole where I'd seen him demonstrate the concave with twin rulers. Funny how these co-incidences occur.

Brett,
I'm not ridden it without a rashie or wetsuit, however I previously had a cork decked board (from Huie) a couple of years ago and traction wasn't a problem.

Bob

looks good Bob! as for me and my household, the pocket is all that really matters!

I often like to just go fast. Both are good.

Looks great!

I'm surprised it isnt super fast, non much to slow it up no fins and little rocker. what do you think is slowing it up?

It's 19.5" wide compared to 21" on my usual board. Possibly the chine from concave to rail as well. Unlike my other boards the tail area is way thinner, with more thickness up front. Perhaps it just needs a bit more testing

Bob

concaves are slower and deep concaves are really "slow," i keep telling people that but no one wants to listen. they automatically think it gives lift, it doesnt, they suck down into the water. " A single concave will enable tighter turns (because its sucks), but it can sometimes stick to a wave face (because its sucks) causing it to track and become less maneuverable (because its sucks). For this reason, many shapers will gradually introduce a double concave to their surfboards." ~ surf science

flat is fastest! double concaves are faster than single but not as fast as flat. also, the more chop the crappier a board with concave works, same with channels but for different reasons.

the "slow" is what is putting you in the pocket and if you trust it, you will get sooooo deep you wont hear a sound and thats what is really addictive. the brown board with the super deep concave i posted a a while ago has the same problem. problem? hahahhaha, its a pure tube rider and that my friends is pure nirvana. embrace the "slow!" ;?}

flat,flat,flat I am a member of the flat world people and flat board people

I've had 4 boards made based on one of Larry Goddard's designs. Board 4 had a concave and was a bit slower but not enormously slower. Board # 3 was narrower & thinner and a bit slower. The concave certainly grips the face better and is the best tuberider.

Given a board is the sum of its parts, the concave + less area in the tail had been my guess. Larry's S was a bit further back to give float in this area, this was part of his design for speed.

I have a flat version #2, it is the fastest of all. I really like the board but it wasn't a great tube rider.

Double concave with some v was discussed if I got another board made in this series.

Bob

Hi Bob, Ive come to that understanding that Flat is Fastest, especially for prone boards. Sure concaves and channels give grip but with a limited area to work with flat uses 100% to reflect the power of the rising water.
I'm not sure if a mat is faster tho ...probably not.

soulglider wrote:concaves are slower and deep concaves are really "slow," i keep telling people that but no one wants to listen. they automatically think it gives lift, it doesnt, they suck down into the water. " A single concave will enable tighter turns (because its sucks), but it can sometimes stick to a wave face (because its sucks) causing it to track and become less maneuverable (because its sucks). For this reason, many shapers will gradually introduce a double concave to their surfboards." ~ surf science

flat is fastest! double concaves are faster than single but not as fast as flat. also, the more chop the crappier a board with concave works, same with channels but for different reasons.

the "slow" is what is putting you in the pocket and if you trust it, you will get sooooo deep you wont hear a sound and thats what is really addictive. the brown board with the super deep concave i posted a a while ago has the same problem. problem? hahahhaha, its a pure tube rider and that my friends is pure nirvana. embrace the "slow!" ;?}

Interesting stuff.

I had though that the concave on my foam and fibreglass paipo was a big part of what was making it faster than my old bodyboards with outer edge channels, but maybe it the fact that they are just stiffer? I had wanted to try a custom bodyboard with the single deep concave to V hull, to see if it speeded one up, but seems from your info that would be a wasted experiment.

If my memory is right simmons had come to the deep single concaves on his boards as with his brothers invention of the strain gauge that was the shape in testing he had found to have least resistance through the water Was he doing something in his testing that was not correct in regards to planing on a wave face?

So next question would be does the drag of a deep single concave on a finless board end up being as fast as a flat board with fin/s due the slowing of fin drag = slowing of concave.

"Flat" for me is flat front to back and side to side. You can't really have a flat board with concave. But a board with rocker can have concave that flattens the rocker along the centreline (stringer)
The concave reduces the original rocker making it potentially faster than the original shape, but still not as fast as Flat.

Fins add minimal drag, but the 'direction' you get from them allows you to travel in a straighter line thus appearing to be faster from A to B.
I've used heaps of commercial fins and home made 3mm flat Aluminium fins and the control is almost identical. The thin fins have almost zero form drag. I set them with zero toe-in and ~6 deg cant. In a straight line they're almost invisible to feel but they hold like any standard fin.

Latest fin build...


Sorry to get away from the Topic.

Brett,
If you had the address I'd write to the people. Snail mail. back to finless.

Bob

So simmons ended up with concave to flatten the rocker? making his test model have less drag?

I would be interesting to be able to see at full speed rear inside corner being the only point of contact whats going on back there, with B's and my board having a V chine back there maybe we are just left on a flat

You must look at concaves as water pressure enhancing nozzles, flat is the best way to relieve pressure

As far as I've seen Simmons tested his boards on flat water, I remember pics of his M2 board. A concave on flat water plane resembles a catamaran so it would have less wetted area and less drag but waves are round and I haven't seen any real water testing on waves from anyone. The closest testing would be real surfing.
Also I would suggest that his testing method is flawed because pulling a board is totally different to allowing the board to create its own speed from the wave.
It's like pulling a model T and a Ferrari to see which one will be the fastest !

Surffoils is right, although I would add that Simmons' concave was open-ended and meant to relieve pressure/drag by enhancing water flow, not by providing lift. Concaves do change the shape of the hull and the rail for that matter. Secondly, Simmons' application of wing foil theory to surfboard rails, and the placement of fins on the rails are much more important and directly related to surfcraft design and function, than Lord's hull "aspect ratio" discoveries. Surfcraft are "surfed" more on the rail than on the bottom. For me, the bottom is most important in terms of how it impacts the shape of the rail.

Thomas,

If you were to make a finless board what would it look like?

Bob