Well, I'm really seriously considering putting T-foil rudders on my F12 design (actually I have already decided doing that). As I have insufficient funds to buy T-foils I'm considering building my own over this winter. Sanding and glassing a rudderboard over is something I can do at my small appartment (highrise building).

I seem to remember having a 19 mm piece of ply wood laying around. With planing and sanding I should be able to get it to mirror a NACA010 or NACA012 profile. Then glass or carbon over the outside and cut the bottom off to become the T-foil. Sail with it for a while on my F16 and when satisfied with the potential make a proper one or buy a commercially made one.

I have to do this as I have AHPC rudders and they have a Shark Fin ending. Basically I have to saw off the bottom 3 inches to even get a surface area large and wide enough to take the T-foil and screws. I think my rudders are at the bare minimum of length anyway, they do stall on me now and then. So that doesn't seem like an attractive route.

I think your VWM rudder blades are alot better in this respect. You have a tapered ending right, with a square tip ? Matt, told me he that he makes the Blade F16 rudders longer then AHPC (a good decision in my opinion). I guess you could just take the bottom egde off to get a flat surface area and prepare the foam to take the screws and the loadings. Probably take a bit of foam out and fill it up again with resin and filler. Ask Matt what you should do here or have him do it for you. Maybe Matt is interested in doing it as an experiment where you cover part of the costs I don't know.

The T-foil can be fitted to this prepared rudder tip. How you make the T-foil is varied, whatever suits you best.

Wouter