I always have a heart to assist an Irishman.
First, is this the correct boat: http://cdn.yacht4web.com/users/8779/low/COLVIC%20CRAFT%20Colvic%2027%20salty%20dog~yw652535-11.jpg
If so, I have a suggestion for a replacement rudder. I have the same on my boat, smaller and trailered. If you let the boat dry out, you may need to rig a temporary leg to prevent the boat from resting on the rudder. I can only imagine how much pressure that puts on the little rudder.
Stainless steel (INOX) rudderhead, robust lifting mechanism. Not inexpensive, plus shipping overseas.
I have no connection to the company but as an endorser, they make a strong product. I am tough on boats.