I've purchased a 1.5" diameter, 18" extension for the rudder 1.5" diameter rudder post, plus a 12" SS tube that slip fits over it (and the existing rudder post).
But I'm having cold feet. There are all sorts of little issues on how to stretch the rudder post, and the fact that I can't find anyone on the internet who's done it gives me pause.
1) The 4" diameter fiberglass rudder tube is now glassed in place, extending about 5" above the cockpit sole, which is about 16" above the waterline.
2) The existing rudder post top is squared off for its top 3 inches (to accept the emergency tiller), and tops off at about 6 inches above the waterline.
3) I can't permanently attach the new rudder extension to the rudder post using the SS tube and some high strength potting material because then I'll never be able to drop the rudder for maintenance in the future.
So I need to be able to:
4) Permanently secure the SS tube to the extension,
5) Strongly and not-permanently secure the SS tube/extension combination to the rudder post
6) Have a way to get at said attachment in the middle of the glassed-in rudder tube to un-secure it, pulling the extension out through the cockpit, and the original rudder post down through the hull for maintenance.
The only thing I've come up with is to:
7) cut out a section the glass rudder tube right around the join. The missing section of rudder tube can be replaced with a high strength rubber boot and hose clamps.
8) Then, after having secured the SS tube to the extension via thickened epoxy, pack the resulting SS Tube socket with more thickened epoxy and slip the existing rudder post with it's squared top generously coated with releasing wax into the socket and let cure.
9) Once it's all setup, drill through the SS Tube and some of the rudder post to put in several set screws. My assumption is that the thickened epoxy working against the squared section of the rudder post will handle the rotational forces, but I need something to keep the extension/tiller from pulling the socket slowly upwards.
I'm really not happy with this solution: it just seems like I've replaced the multiple failure modes of a wheel with multiple failure modes of a strangely coupled shaft. Can this setup handle the tens of thousands of cycle loads it needs to? Because it's, you know, the steering.
Should I instead be getting a shaft extension welded on? It's very hard to get that done right, too.