Newbie here. Weed fin question. I understand the normal weed fin design moves the center of pressure back compared to a normal fin. If so, why not shape the fin in way that attempts to keep the center of pressure in the same spot as a normal fin? See diagram, not to scale, just to get the idea across.
Select to expand quotegraygeezer said..
Newbie here. Weed fin question. I understand the normal weed fin design moves the center of pressure back compared to a normal fin. If so, why not shape the fin in way that attempts to keep the center of pressure in the same spot as a normal fin? See diagram, not to scale, just to get the idea across.
Many do :-
Tectonic Speed Demon
UFO Weed Forward
Tribal Delta Sym
Unifiber Lessacher Anti-Weed
Black Project Kestrel
etc.
You have drawn 3 different fins there too. Pointer weedspeed & delta. Range of use - no weed, some weed and thick weed in shallow flat water.
The problem is mechanical, you can't shift a fin of any size forward enough, because it's attachment would be too weak.
Your example is very close to how a lot of us make our fins, that fin is short enough for the thickest part of the fin to still be in the box.
But I don't do it like that my boxes are set 10mm further forward in the board, because I always use shortish weedies.
If you have mild weed you can use a more upright fin with less rake, the denser the weed (or a shallow start) is, the more rake.
Sailing predominantly with weedies, it's just a case of shifting your mast base back further.
Tribal weed speeds are a pretty good compromise, but best suited for lighter weed spots due to less rake.
A fillet helps a little spreading the load, but even with 3D printed fins, I can put the box way aft with no structural failures...yet. 
