If you take a look at the beautiful job that Performance Catamarans of Santa Ana, California did on the new Nacra 580, you'll find that a kick up centerboard, that has a proper foil shape, can indeed be self sealing with no added gaskets.
Pictures of the Nacra 580 with kick up centerboards

This centerboard seals the trunk when it is fully retracted and it also seals the trunk when it is fully extended.

Flashback in time: Check out my April Fools Post from 2003:

Quote
A Nacra Formula 20 CB is the centerboard version of the F20 boat
that is based on their new F18. The hull shapes are very similar to
the newer Nacra F18 but a bit larger. They are narrow, have a very
fine entry, tall plumb bows, and a super-cool ultra thin walled
chromium-alloy (chromolly) super strong and lightweight mast that
has better flex characteristics than other current aluminum or
carbon fiber masts.

The centerboards are high aspect ratio eliptical shaped foils that
employ a new centerboard gasketing system that provides a near
perfect seal in all the centerboard trunk that is not occupied by
the long slender foil. When the boards are lifted half way up, they
swing so far aft that the center of lateral resistance is moved
significanlty aft and thus provides a superior resistance to
broaching.

It's my dream; very much a dream boat!

GARY
post



GARY

Attached Files
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Santa Monica Bay
Mystere 6.0 "Whisk" <--- R.I.P.