Best way to make a daggerboard

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#1

Hi,

I would like your opinion on the best way to make a catamaran dagger board. The profile is an airfoil. It will be a copy of the one in the picture. The original is made in 2 halves. Each halves has the skin laminated then high density foam is poured in the halves. they cut the excess foam to create a flat surface and the 2 foam faces are glued together.

I could use the same method but would like to make it one piece and empty to reduce weight. Some ribs will probably be necessary inside. I would like to use carbon fiber.

#2

These foils are under a LOT of stress at times. I wouldn’t even consider using a hollow structure to handle the loads.
Henny has a good set of pictures and some notes here

#3

https://www.youtube.com/watch?v=ToUGy07JUVY

those are hollow…
Unfortunuately I cannot disclose anything about how they’re build.
But I know of other foils which are build with siliconerubber inserts which get pulled out.

#4

I would imagine that those a built much like the hollow foils made by other large marine composite shops. Monolithic skins with hollow square tubes bonded between them.

#5

I can comment on that, as it is previously publicised. The foils in the video are made in one shot, no glue, no secondary bonding. one autoclave cure for the whole structure. I believe forum member fasta could be doing something similar.
With silicone inserts in a straight section the same could be done.

#6

Thanks for the video link Susho. That’s amazing!