Hi Cowana,The cross section shows where a slit for the triangular fitting will fit and be locked in by as mentioned,by taping up the the thin saw cut made to let the triangular fitting be slotted into place.The shaded area is where I just tape up the cut end so secure the fitting in place.The tape will not come off as it will be trapped inside the foam tube,with the fitting in place.The tubing mentioned is ordinary plastic pipe used in plumming of 1/2"[12.7mm]dia.should be a close fit to the hole in the foam.The triangular fitting must have a minimum width of 5mm otherwise it has too much freedom
for the cross beam to slop around resulting in the float doing the same,although once under pressure
it is held steady by the side pressure.Well done Cowana I see you are pressing ahead ok,hope the info is ok for you.Just noticed notes on the foil.The angle refers to the water surface as Dick says it only needs a small angle of negative angle otherwise you get something like a submarine[Yes OK I've done it and found out the hard way!!!!!????]In those days I had no contacts to put me right
Regards Scotty