Foil section? For foil board

It is hard to see the double concave - actually hard to see any concave at all !?
on the rudder maybe, but that is a symmetrical section.

 

Sorry for late reply,
It minimize drag too, as it minimize leading edge velocities, but the trick with Liebeck wing sections is that they work within a small bucket of AoA.
The Startford recovery typical of these wing section is the shortest possible recovery and therfore the lift is maximize with more of the chord with negative pressure on the upper side.
Googleize AO Smith + High Lift Aerodynamic, I feel confident you will find many academic workpapers on these topics, written by true CFD specialists, I am not a CFD, just an half rookie
Cheers

 

Thanks for your input.
Not easy to find any Liebeck wing profiles that doesn't need serious modification for a windfoil foil section.
I guess it is not desirable to have narrow AoA range for a windfoil ? Stability is key to go fast.
I'm no CFD expert either and a real foil design noob. my first try.
I'm trying to understand all the terms thrown at me The Startford recovery and Googleize AO Smith + High Lift Aerodynamic never heard of those before
just trying to find a decent foil section. Maybe I'll just start out with a NACA 64-210 or similar to get started.

 

I see now, that the NACA 64-210 actually does have a little bit of double concave towards the TE.
very little, but is there.

 

Tom Speer - Home - http://tspeer.com/

Rasmus,
Have a look at the link above mentionned
Tom Speer was CFD guru, he used to work for Boeing Phantom Works department, he has posted great explanations on this forum I feel confident you will find, and he has studied an hydrofoil wing section called H101 or H105, this section should be available on his website or on the forum.

Liebeck's are not for hydrofoil, I mentionned it just for the Stratford Recovery principle, for hydrofoil I would be expecting lower concave on shorter % of the chord.
Starting with Tom Speer's hydrofoil section, and "cooking" it with inverse design method with XFLR5 could be a starting point, but it is just a suggestion, may be there are alternatives I dont know.
Cheers
Erwan