Bottom countours for Small surf

Hello guys.

I have recently started testing out my summer quiver and I decided to share with you some of my inputs.

I’m an extremely light surfer (121 pounds and 5’5 height ) from Costa Rica, and my go-to board is a performance 5’5 x 18 1/8 x 2 1/8, round squash tail. 

I made some experiments on my 3 last boards, changing only the bottom contours of them.( measures stayed 5’3 x 18 1/4 x 2 1/8) - I know there are many variables regarding to foam density, stringer fibers direction, etc… But it was the best I could have done to make all 3 boards look as close as possible.

After many test drives in small waves, what I could realize was that:

1- Deep single concave really increased the board projection trought turns. In other words, it felt that the board kept really good grip on the face of the wave and all the way trought turns. It felt good for long archy moves, and better in a litlle hollower and powerful conditions(specially in better waves with at least 3 feet). However, in opposite to what I always hear, it seemed that the** deep concave had not increased the board speed at all** (specially in small weak surf).

2 - Flat bottons felt really more sensitive and apparently made the board a bit faster and looser. For me this is the perfect bottom for small waves, combined with a swallow tail, giving excellent manouverability in weak conditions. It seemed that the board felt really more alive trought dead sessions, not to mention the speed. 

3 - Single to double concave - I didn’t feel enough difference from this set up compared to the single concave, but the board felt more alive and with more drive in small conditions. I guess it has increased the rail to rail transition with good precision, and the main difference was that the board looked faster in quick turns with less space to work with.

After surfing with those boards, I started to think about the design differences from one bottom contour to another. 

Mainly, in my point of view, it felt that the single concave really makes the board easy to “sunk”. I guess it creates more drag, and for that, gives the board more control, decreasing speed. In my eyes, single concaves doesn’t reduces stringer rocker, instead it increases the rail rocker, making the rails to be more immerse in the water. 

Flat bottoms felt the opposite. Not enough hold or drag, less control, but full speed… A litlle slipery in hollow and perfect conditions, but perfect for small, and mushy surf. The board feels more up to the surface, and it seems to create that lift at the tail.  Really connects well trought turns and really helps you to catch the next session and to make quick manouvers in short spaces. 

Single to double seems that a mix between single to flat bottom. It hold the board well but the double concave at fins area really increases the capacity to put the board on rail while making bottom turns.

Anyway, I would like to ask you guys your opinion, if you agree or not with me, and what’s the best next choice for small wave surfing!

Any inputs, ideas or critical analises are welcome :slight_smile:

Sorry for my english.


Pura Vida Supershape

PS: My perfect combination was a 5’3 with slight single (1/32) to double concave (1/32) - (almost flat) with swallow tail. 




Interesting - would like to hear your feedback for the same boards in decent head high waves - what break did you ride the boards in ?

sounds like a very fun experiment,

I’m guessing (from your findings with the single concave) that the concave was contrated under your front foot and flowing nose to tail.

It’s all subjective.

My findings with single concaves is you (I) have to have the depth of the single concave, around the side thruster fins (the engine room), the same or even more then at the front foot. Giving spark through lift, and tight arking rail pocket turns.

I too find front foot concaves a bit stop-starty. No doubt they can work excellent if the stringer and rail rockers are matched correctlly.

It sounds (of me) you have a consistant stringer rocker, with med-high tail rocker.

…Machine shape - to get the most out of your single (personally the fastest small wave design) - with the same board outline. lower the tail rocker - 1/8, kick (increase) the rocker at front foot (not the tip-must be front foot) move your back slice to 9.5" up add 1/8" concave.

This should get the single working, for a light weight whipet like you… maybe haha. I’m light to, 160 and ride a 5’8" standard shortboard.

Yorky - I just re-read the op’s post - not sure how you came to the conclusion he made the single concave deeper under the front foot.

I guessed…

From his ride reports and my understanding of single concaves.

As I said it’s subjective.

You cant just add different bottom contours without taking into consideration All other design aspects (such as EDIT ‘stringer’ rocker) 

It’s all a game of give and take… Just look at the Flyer from CI, talk about give and take on performance design characterics, hips, doubles, high nose entery, norrowish nose, etc… they all cone together to make a bloody good surfboard…

Single concaves are very good for light surfers (fit surfers riding high perforance short boards).





… if he just added the bottom designs and not changing the stringer rocker… don’t know… don’t really care either.

Just talking, You want speed? single concave is the ultimate.


Re the single concave deeper under the front foot - I recently rode a 6’6" stepup that had the concave deeper under the front foot than by the side fins - it ruined what I believe otherwise would have been a good board - if you tried to turn off the front foot, the board resisted. If you tried to turn off the rear foot - the board stalled as the tail sank.

Ha about time somebody else is my size on here. I’m 5’5" and like 120lbs as well. What’re we talking about when we say “small” waves?

For smaller waves that’re weak or like waist high I like short, stubby boards, so I’ve got a 5’4"x20.5"x2.25" with a kinda rounded vee/hull type entry, deep double which is deepest near the front fins/between my feet, then to medium vee out the back. It’s a very wide board though, 17" at the 1’ from tail and like 15" or so up front. It’s a remake of the same board with a flat bottom. I find that the concave one generates speed more efficiently and seems to go backhand better, especially when pushing the board to slide a bit at the end of a turn. The flat one felt a bit more lifeless when trying to move the board and hop around, although I do think if I just stood there and cruised the flat bottom was quicker and smoother. The flat bottom catered to less aggressive surfing, more or less, which I don’t really do right now. Maybe when I’m older I’ll revisit that design.

For better waves I had a 5’5"x19" flat bottom, although I’m remaking it as a 5’7x19 with a deep single and more overall rocker. I increased the length as to not compress a lot of curve into a very short board. I’m doing as yorky said, with the single concave being deeper near the fins/between the feet than in the middle and under the front foot. Seems to give it that propulsion effect. The flat one felt sort of lifeless, again, when moving the board and hopping around. If the wave had some power or a steep face then the flat one felt better, but I still like how concaves feel over flat bottoms. 

I’ve never really had something like if I just went to the store and bought a 5’5"x18 1/8" performance shortboard. 19" seems versatile without too much penalty as far as sensitivty edge to edge goes.

Hey York, how are you my friend? 

Thanks a lot for sharing your thoughts with us.

In my designs, I always make the single concave deeper between the fins area. 

I once tried to put the single concave deeper under my front foot, but it turned out to be cathastrophic, just like patrickfreen have said. The board felt so stuck on small waves (up to 3 feet) and I had to keep putting all my body weight foward so the board could get enough speed. I personally didn’t like it, but of course, this is my opinion based on the board that I’ve made. Since I like faster boards without having to lean my body forward, I was forced to sold that board and later I made a new one putting the concave deeper between the fins… It felt like the balance point was back to the best position for me (right before the front foot).

As for a theorical analisys on that factor, I have to return to my previous toughts… The deeper the concave, the more drag your surfboard will have… If this drag is placed mostly under your front foot, you will be late for manouvers and turns, and you would have to make a huge effort to compansate that drag, i.e leaning your body forward… If the deeper concave is placed between your fins, it could make your turns a lot more precise, since the drag is concentrated there, helping to hold the tail a litlle bit longer trought turns.

For me, singles don’t lift up the board, specially when placed in the midlle of the board, where you have the widest point and the most concentration of volume and wheight.

Maybe between the fins it could lift the tail a bit, but I don’t know what benefit it could provide.


You’re totally right when you say that a lot of other factors matters… For sure you can find a good combination that the deeeper single concave under the front foot will work better than what I’ve experienced. But in my boards (I work in the same model for over 8 years, improoving just a few points), it didn’t feel like the way to go. Maybe with front footed surfers, or beginners, or hollow barrelling waves…

I surf with my weight backwords, and I like fast and easy boards to ride (larger and shorter). Since I’m not a pro, I don’t care much about having extreme precision trought my turns. My most concern is a board that stays on top of the water and have plenty of speed to carve and performe in non classical conditions…

I once rode a DHD 5’8 (project 15) that was amazing in small conditions… I tried to make a replica but it didn’t work the same, and not even close…

I guess lamination plays a huge factor at the board wheight and the quality of the surfboard blank also matters a lot when making replicas…

Anyway, let’s share more toughts…



Hey my friend drzoidberg, I’m referring to waves up to 3 feet, mostly beach breakes.

Yes, it’s hard to find someone with our size and weight.

I was surfing a lot with stubby boards as well… like 5’4 x 19 x 2 1/8 (swaush tail) or 5’3 x 19 1/2 x 2 3/16 (half moon tail) . I think going wider is good to make the board alive in really small mushy conditions… But when it gets bigger I think those boards are a litlle unprecise and tend to be slippery while carving… Maybe with a greater concave between the fins, or with a wing to reduce the tail area, those boards can be a litlle bit more accurate and hold on better trought turns…

For me, if you put a flat bottom in a very large board, it would work like a fish, going super fast but without projection and precision while carving or aiming to hit the lip.

Did you feel the flat bottom holding the board better comparing to the concave (on hollower waves)? For me it felt exaclty the opposite… In powerfull waves, the concaves gave me more controll. 

I’m right now inclined to surf with a small performance wave shortboard (5’3 x 18 3/16 x 2 1/8), with full rails, almost none concave (just 1/16 of double conc. between fins) and a wider tail to increase release and manouverability in short spaces… Maybe in the next model I’m going to try a small swallow tail to reduce tail area and add more control during turns, or even a wing remembering a performance fish.

Have you ever tried to surf with narrower boards, with less than 19"? I guess it’s a good combination with flat bottoms. The narrower you get, the more the board feel stuck and precise, but with the flat bottom it kinda compansates it, and gives the board a litlle freedom and manouverability.

The good thing about this discussions is hearing other thoughts and experiences… Maybe the way we surf is so different that some elements work for you and not for me, or vice-versa… 

That’s why I love being a shaper and have the chance to study this design elements, and try to fit them toghether personally to each surfer :slight_smile:

That is why surfboards are customized, and I hope it never changes.,

Thanks for sharing, cheers my friend!





Here’s my take on bottom contours for what it’s worth: Unless you’re a skilled shaper I’d recommend sticking to flat bottoms. Much easier to shape. They’re a nice neutral design.

I’ve made identical boards with concaves and without. I couldn’t tell the difference. Kelly Slater probably would, but as an average surfer and shaper I can’t. I used to put a V in my guns, but now I don’t even bother with that. It’s all flat bottom for me nowadays!

I’m sure there are much better shapers on this site than myself who could make a concave board where you would notice the difference. I’m just not that skilled yet.  



what about vee? alot of small wave low aspect ratio boards (think firewire potato series and lost bean bag i think?) utilize a lot of vee.

I guess the V helps the board to always be prepared for a rail to rail transaction…  Helps to carve at the pocket of the wave…

I personally put a litlle V on the tail of one of my models, but I couldn’t realize any difference… I couldn’t feel any improvement on carving or drawing a cut back, for example. Maybe it was such a small V that didn’t make any difference at all… (almost 1/16V from the tail up to 2")

Just want to say that i love what you have done with this. something i would have always loved to do with more time and more resources, CHAMPION EFFORT.

Before some SWALOTROLL tells me its all been done before, i know, but credit where credit is due, great work Supershape…