Wooden Fin Strength

General Discussion
1

I’ve been loaded with questions lately, so i figured now is a better time then never to unload them here…

 

Okay, so i’ve been foiling some wooden fins (dee, pins, hucks) and saw greenlight had tabs for wooden fins so you can make them compatable with boxes.  I’m making these fins from 1/2" baltic birch (common ‘craft’ plywood), so they’re a little thicker than most box fins… that’s not the problem though, as i can always take them to a table saw to thin out the bottoms need be…

The real question is how much glass would they need to be tolerably strong, with out making them awkwardly thick? what weight? and how necessary is roving to make a halo around the fin? i’m not saying i’m a surfer who runs there boards into the beach, but who knows who will be borrowing the board, and on empty days i usually ride without a leash.  also, spots out furhter east on the island have rocky shores…

and if the required amount of glass will make them too thick, what size plywood should I step down to?

Thanks for the info duders.

2

I guess only a proper seal would be necessary. They won t last long though

 

My advice would be 2 layers of 6 oz both sides and to put roving at least on your leading edge. A couple of millimeters halo is fine. thickness is fine but make sure you foil them without any flat spots. try making glass ons first. Cut the outline but make the fin a few inches deeper. This helps with clamping and doing both sides (trailing and leading edge) in one go. This also makes for a nice flowing foil. Don’t worry about the weight too much they will end up lighter then anything else compared to g10. A thicker foil will also be more efficient in creating more lift

 

good luck and maybe try the search button there is a lot of info out there on this subject