Jane
I used to have a 22, my lump of steel was plated both sides with plywood, shaped to an areofoil, which almost makes it float, thus seeming lighter to lift. I later replaced it with a stainless stell plate, about 1/2 size, with holes as well, this plated up and glassed worked very well, and much lighter.
On my Jenneau Bahia I fabficated a 21 style rudder with aluminium stock and multi layer plywood shaped blade, glass covered. I took the pattern from a 21.
Philip