Thanks carlbohannon.
that was quite a journey thru the RC airplane world.
Seems that more links are dead there than in cat sailing ?
Now I know how to build a foam cutter in 4 days from HomeDepot parts, sanding, vac bagging with a 40$ pump, getting stringer in with an iron etc.

But I rather prefer to use a somekind smaller daggerboard
if I can get one ready made, before I start that adventure.
At this moment, I just try to plane and sand down some plywood and put some epoxy around it.

But anyway, thanks for the insight into the foam wing world.
May come in handy later.
What was that part of you making those things ?

Michael