If you want to make another rudder it is relatively easy. The best construction is marine plywood (teak ply would look stunning), covered in epoxy/fibreglass, then finally a layer of varnish or paint. You could use your rudder to have a piece of plywood cut or I'm sure a template is available somewhere.
The same applies to the rudder stock.
Done right you should end up with something strong AND very attractive.
Bristol 31.1, San Francisco Bay