Hi guys,

What shape do you make the top of your keelfins?
Basically the foil section that is inside the hull/trunk.

I know the two basic plan forms are:
  1. You cut the rear or forward section of the fin at an angle which allows the fin to be drawn up tightly into the trunk.
  2. You build a section slightly narrower than the width of the keel with angled sides and this allows you to pull the fin up and adust it forwards and backward for ballance.

But what is the plan view of that section? if you want to be able to adjust it forwards and backwards then surely the trunk and the appropriate bit of the fin needs to have straight, parallel sides?
How on earth do you build that? If you do get that correct, then what happens to the hole in the hull to accommodate the keel fin? It would need to be long and then you have this hole when it's in the water to mes up the flow? I figured you could just use some play-doh or something to fill it?