"Toller" wrote ...
SNIP
Is there anything inherently wrong with making a solid rudder, possibly
covered with fiberglass? . . .

Toller,
If we are talking about the two 'outside' pieces that hold the lower 'blade'
to the upper 'stock' . . . mine are made COMPLETELY of 'fiberglass'.

MY P19 is a 1989 'vintage'. While I have heard of 'aluminum' side plates,
I've never seen any, or know when they were 'current'. I have accidentally
'grounded' a few times, and had the rudder shoved upward, out of it's
gudgeons, a couple of times. Once I've even been shoved by a current
BACKWARD into a mud-bank and had the rudder blade jammed in and taking all
the force. I was 'pinned' in place and had to struggle to pull the entire
rudder out of the gudgeons to get free. With all these 'events' . . . the
'cheeks' look brand new.

They are only about 1/4 to 3/8 inch thick. Their strength is partially due
to the 'shape' molded in to them. A 'half-circle' ridge is molded in, about
a half-inch in from the edge. Each 'cheek' is approximately square, with
rounded corners. The edge is unfinished. The outer surface is heavily 'gel
coated', the inner is not.

If it were up to me, and I HAD to do it {because of extreme expense, or
non-availability}, I would duplicate this structure. Make a mould out of
wood {router and a round-nose bit should do nicely}. Slather it with wax as
a 'release agent', let dry, then buff. Now slather on a layer of 'gelcoat'
{available in half-pint cans - should be more then enough} and let cure. Now
simply build up your own 'fiberglass substrate'. For this I wouldn't use any
'roving' or 'mat'. Just layers & layers of 6 to 10 oz. cloth - well
impregnated with EPOXY and well squeezed together. Let the whole mess cure -
well. Pop it out of the mold, trim & file the edges, mark the holes {using
the original as a template}, and drill. For the sake of paranoia, give the
holes & raw edges a coating of epoxy and let cure.

And 'Bob's your Uncle' !!

IF you have the epoxy and cloth available, or can get it at a REASONABLE
price, the cost factor is low. It's mostly a case of TIME and PATIENCE.

Regards & Good Luck,
Ron Magen
Backyard Boatshop