ideas needed to mount hydrofoil to board

[ChristoffM]

I made a hydrofoil out of plywood and fiberglass. The keel part is nice rigid aluminium extrusion. Now I need to tie the hydrofoil to the kiteboard in such a way that it can be assembled/disassembled for transport.

My first try was to epoxy the extrusion into a 1.5inch thick block of wood, and reinforce with fiberglass. I hen bolted the block of wood to the board. This worked well structurally, but the water drag is way too much. I thought it would not matter since the board lifts off the water, but getting the board going fast enough so that the foil can lift is proving difficult.

The board is only about 2inch thick. I was thinking of putting tuttlebox insets into the board, and tying the hydrofoil on like a fin. But I do not know if this would be strong enough, and I cannot get any tuttlebox inserts in South Africa. So now I wonder whether it is possible to cast my own mold using resin.

Does anyone have any ideas?

[ChristoffM]

Here's a picture of what I have now:

[edt]

mount that wood on top of your board, right? Of course you have to cut a slit thru the board and finish it however you are finishing your board and make an extra attachment so you can unbolt or bolt through the keel to your block of wood. where did you buy the keel from, btw.

[ChristoffM]

Top of the board would be difficult. That is where my rear foot goes, and I don't know how I will connect the wood to the keel in a removable way.

The keel is an extrusion off cut I found. The people that do alluminium extrusions in this country has a nice airfoil mold to make 1000's of meters of this extrusions, but the minimum order quantity is huge. Next time I will try using air foiled hang glider down tubes. They might need one layer of fiberglass to stiffen them up slightly.

[cookiemonster]

Did you try to profile the piece of wood fixed under the board?



that should reduce the drag enough.
After you'll have to play with the angles on front/rear wings to get the correct lift

[ChristoffM]

No, I did not streamline the first one. (I did not think it important then). Maybe that is the easiest route to go. Thanks.

[wil]

hi I see you are using a North 2010 race board. Have you made anymore progress with bolting your foil to the board. Can you show both sides of the board. I am planning to buy a North 2010 raceboard and attach a hydrofoil.