I'm a big fan of skegs for safety and directional reasons. If you
ground by the stern with a spade rudder, usually it's game over. A
skeg can help...maybe...to save it.


Just to clarify: That is a fixed skeg shown on my proposed
modification.

On spade rudders: On power boats, I favor spade rudders. If the
rudder has good clearance from the hull at the top, it will often
remain functional after a grounding. The shaft may bend and the boat
steer funny but it will still be steerable. With a bottom bearing, a
little bit of bending will usually bind the whole thing up so if is
useless. In a glass boat, it will be hard to make the skeg stiff
enough to support the rudder. The whole thing can flex enough that
the shaft will bend and the skeg will then bind the rudder. Even in
metal, the sailboat type skeg will be hard to make sufficiently stiff.

It doesn't take a lot of extra metal to make a rudder stock strong to
be self supporting. If I were designing a boat that was not a weight
critical racer, I would make the stock large enough to be a spade
rudder. The skeg would then be structurally separate with just a line
guard at the bottom. Grounding damage, which usually will bend the
stock aft, would then leave the boat steerable in most cases.

--

Roger Long