...making a quality symmetric curved foil is incredibly more difficult than making a straight one. The tooling alone requires a lot more material, engineering (with quality software tools), and time. The foils on the F20c are truly a piece of art. They're very very light (they float!) and they're obviously very strong...
From my limited experience:
- An asymetrical foil is slightly more difficult/expensive to make than a symetrical one. The same goes for its trunk.
- A curved foil is a little more difficult/expensive to make than a straight one, if built from female molds. The same goes for the trunk. Making the plugs and molds is obviously more expensive, though.
- A curved foil built over CNC machined foam can be extremely expensive, although easier to laminate, if the reinforcements are smartly designed.
- The number of localized reinforcement layers in a lifting foil increase as the vertical load grows as % of displacement.
Each of my boat's straight assymetric boards was designed to lift 50% of displacement, which is probably close enough to the F20c foils, from what I saw on the video.
My foils were built about eight years ago in a small Brazilian shipyard in foam/glass/estervinylic - and they also float. In view of that, the fact that the F20c carbon boards can float is meaningless.
If they are building the F20c foils from female molds as we did, its price depends on the materials, weight and number of layers, labour following the number of layers.
It seems reasonable to charge 20% over the price of a straight symetric foil of similar build (female moulds, same materials, same technique).
However, if they are not building over CNC machined foam, the prices should be a lot lower. I hope this is what is going on, for the quoted prices are outrageous.
Just my opinion, of course.
