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Building a lightweight compact plywood hydrofoil board

Posted: Wed Sep 20, 2017 1:22 am
by RadDrDuke
Is it possible?

Basically a little bigger than a wakeskate, with the amount of thin ply can it actually be lightweight or does it need to be foam to be reasonably light for air-travel?

Re: Building a lightweight compact plywood hydrofoil board

Posted: Wed Sep 20, 2017 1:36 am
by Jyoder
Mine is 10 lbs (4.5 kg) with glass but no carbon. Could probably get it down to 8 lbs (3.6 kg) if I made it a bit smaller and belt sanded the sides and front to be thinner. Ply boards are durable but not light. I can toss mine around in the car or on sand without worry.

Re: Building a lightweight compact plywood hydrofoil board

Posted: Wed Sep 20, 2017 7:25 am
by K-Roy
I give it a try and loved it. On land it was indistructable, however on the water it snapped in half like a toothpick when I hit a fish at high speed.
No glass or carbon, just 15mm plywood.( 112x40cm; 3.2kg.)

Let me know how you get on, I like to bild an other one this winter...

cheers

Re: Building a lightweight compact plywood hydrofoil board

Posted: Wed Sep 20, 2017 12:09 pm
by Starsky
Not sure a full wood core can be light too.

I have a skim that works well, but to get one that was stiff enough it comes in at almost 10 lbs. 5 layers of hardwood with high density plastic laminate on top and bottom.

Re: Building a lightweight compact plywood hydrofoil board

Posted: Wed Sep 20, 2017 12:47 pm
by kiterocky
Just buy a wakeskate...or a skim

Re: Building a lightweight compact plywood hydrofoil board

Posted: Wed Sep 20, 2017 3:57 pm
by BWD
3mm birch plywood for deck and bottom.
1" Extruded polystyrene foam core.
Wood blocks or stringers around foil position.
Rails can be light wood strips, shaped foam, etc.
Cheap strong and stiff.
150x50 should be around 3.5 kg, less
If you go smaller or use lighter EPS foam, can be a little lighter but you may need some carbon patches and stringers. Even lighter if you skip the ply and use carbon and glass.
But you can get pretty good, easy build and light enough just by using thin ply around a layer of foam instead of ply in the middle.

Re: Building a lightweight compact plywood hydrofoil board

Posted: Wed Sep 20, 2017 4:41 pm
by edt
How does plywood have enough flotation to keep the hydrofoil from sinking to the bottom? I have a liquid force hydrofoil aluminum, there's no way my skimboard would float it.

Re: Building a lightweight compact plywood hydrofoil board

Posted: Wed Sep 20, 2017 4:53 pm
by BWD
Good point! If birch or other heavy wood, it would have to be a big board.
My 66"x18" cedar/glass paipo (~3.5kg) floats my 3.8kg zeeko with only the front 6" above water. In chop it once took half an hour to find it. Wouldn't float a LF or takuma at all I think.
Once I pushed it down with my feet -accidentally- into a slight current and it took a good 30 seconds to come up, somewhere else.
If I cut 6-12" off it it would just sink. Now it has 8" of pool noodle on deck between the old fin holes. Much better!
I plan to build a shorter, more buoyant one with a foam core as above.

Re: Building a lightweight compact plywood hydrofoil board

Posted: Wed Sep 20, 2017 5:20 pm
by Jyoder
My full length deck pad provides plenty of flotation for board and Alu foil.