'rudder - shudder...
Bill, These are NOT rocket science, naval archtects re-vamp, and revise plans on rudders, or placements alla time.You can find a used rudder that "looks" like yours, bigger is better for a cruiser, a racer, yes needs to be much more precise, but look at these 'survival' rudders; heck some warps towed aft will steer you.Or rebuild yours outta foam then glass it with micro-ballon, and some cloth if needed. There is always a simpler, and cheaper way.