Hi,
I am in the middle of designing my first Efoil board shape.
my only variable that i am not sure about is the bottom contour.
should it be a flat or maybe convex?
thanks in advanced.
Shahar.
I recommend concave in the front half for early lift, tapering to flat for you foil connection. Its kind of the easiest option.
If you really want to put some work in you could put a heavy double concave with a raised center chine. This has the advantage of reducing ‘sticking’ when you come down off the foil.
1 Like
Thanks @michion for the advice, i will take it under the consideration, looks like that both of them will work great in choppy water as well.
I would go for flat, the board does not spend that much time in the water. A shape is nice to look at but the extra work to get it done is just not worth it.
3 Likes
A rotary cut with a hot wire cutter will add strength to the nose, this will be my next build. ,
The cut out could then be used as a rear “chine”
Easy to draw a little harder to make.
.
thanks @Riwi, i thought about that too, but i wander if there is much different in choppy water for the first meters on the water.
looks interesting…
You would need a deep v-hull to cope with that type of sea. Not so practical and way harder to build. If the sea is rough you will learn to use the waves when starting. It all about practice.
My two first boards were old sup/surfboards. Works and is simple to modify.
For my third build I decided to make my own board. It’s so much work. I don’t know if I will do it again.
Keep it simple. Good luck!
1 Like
@Dynamik please no more private messages on this topic. Can you share your impressive skills on the public forum so others can gain from your knowledge. 
From Dynamik" Dynamik
Hi, I think this shape of the bottom of the board https://efoil.builders/uploads/default/original/2X/0/09b910d74444786de5047d31059e2ee66be126fd.jpeg is not at all suitable for e-foil.
Hydrodynamics for e-foil is a rocket science. This is the main reason that there are most posts on the forum about finding out the ideal shape of the propeller, pipe and wing. So far, there has been no one on the forum who can solve these tasks.
I’m a hydrodynamic specialist. I have been researching and developing technology (propellers, turbines, pumps, …) for many years, which uses hydrodynamics - optimizing hydrodynamics, modeling in 3D CAD, prototyping, measuring efficiency, etc. I am also the author of a new physical rule that allows you to design a propeller, wing and bottom of the board with the highest parameters in the world.
How did you find out that the lower part of the board (pictured) is ideal for e-foil?
Thanks
Peter, EU"
Lets chat !
How about Peter (@Dynamik) gives us some real credentials and company details to back all his criticism. Or link us to his paper where his new “physical rule” is demonstrated with factual evidence. Hell even a video of one of his propellers running in the water would be good at this stage…
2 Likes
@Dynamik please share your thoughts about this topic, and if you have more info about the board specifications it would be great,
thanks.
Hell even a video of one hand stroking his ego would proof . …we do not need to see that video? lets just say peter AKA “DNT” etc… maybe a stalker ? Lets get back to the bottom of the board. I consider having turbulence to avoid stick is an advantage. the prior proposals are basic concepts that are not optimised. I was just making a suggestion, other options will be better.
1 Like
I’ve never had problems with any of my boards (all flat bottomed) “sticking” and the one board I ride is only 60L and I am 90Kg.
1 Like
Dynamik is a difficult charakter, but he have no facts for his themes 
My Boards have a little V… It’s OK so.
Greetings Frank
1 Like
I’m with you on this one no doubt
Thanks guys for the info, i will take it under consideration 
Yeah I got the same pm.
He’s such a troll.
1 Like
I find concaves much smoother through the water. Less ‘slapping’ through chop. Most boards I own from surfboards to sups to wingfoiling boards all have a concave through the nose for this reason, and early lift. It’s not there for looks.
I usually put in about 15mm of concave which isn’t much work.
3 Likes
It’s not really a problem. More of a feel of how the board touches down and releases again.
From all our different builds we can see pretty much anything works for an efoil.
I enjoy seeing new shapes and features and there affects on riding characteristics. Building to the status quo is boring.
2 Likes