Choco, damm you... I hadn't till you mentioned it...boy, that opens a can of worms. I asked chat GPT to design a fin that doesn't spinout, then a fin that can do 60kts....then down the rabbit hole from there. A couple of very interesting new concepts I'd not heard about or considered were introduced....a few appear to be easy to model/3D print1) V-shaped cuts in the leading edge at base of fin on each side at an angle of between 20-40deg. Purpose: The V-shape helps improve stability by creating a more defined leading edge flow path. This makes the fin less likely to veer off course or experience drag when turning into the wind or changing direction (as in tacking).
The cuts also reduce the amount of water contact at the base, which helps keep the fin clean and efficient in turbulent water.
I can't find any examples/images of this but attached image is what I think it means...anyone have a clue?
2) Apply sharkskin texture to the surface. Purpose: Adding a shark-skin-like texture to the leading edge of the fin could reduce drag and turbulence, helping the fin remain efficient at high speeds and prevent spinouts when you're pushing hard.
3) Winglets or bulbs. According to ChatGPT bulbs at the tip of the fin increase low speed stability whilst winglets increase high speed stability.
4) Applying washout along the length of the fin (i.e. Prandtl)
There are harder to implement suggestions like variable rake and variable angle of attack fins using foot strap pressure.
Interestingly 1,3&4 are recommended for a windsurf fin capable of above 60kts. Instead of Sharkskin texture suggests applying a hydrophobic coating like NANOMYTE? SuperCN
