For anyone interested in this topic, I did the compression post repair on my H34 over the winter. I did nearly exactly the same thing dcalif did (2x2x0.25 aluminum square tube with a honking big header block at the top), with one major difference compared to what anyone else has done as far (as far as I can tell) - I left the mast on throughout the process. I estimated the mast and rigging couldn't weigh much more than 500lb, so I loosened off all the standing rigging and just jacked things up. At night I would slip the old post back in just beside the opening I was making so that when the bottle jacks leaked down (and they always did) it would hold things up. I also made a relatively small opening through the transverse beam, only about 4 inches by 6 inches (which made it tricky hollowing things out enough to get my 3 in. by 8 in. by 1-1/2 in thick header in). The net result, though, was that I only needed trim pieces 1-1/2 inches wide to cover the hole when it was done.
I'm really pleased with the result, even though it took over four months to do it. Total cost was about CAD $800.
A comment about the original design: douglas fir has a compressive strength of only about 340 psi perpendicular to the grain. This means that the wood inside the original transverse beam directly above the compression post was not even capable of 5,000 pounds, which is nowhere near strong enough to support the mast on a boat of this size. Even though the beam on my boat crushed down between 1/4 and 1/2 an inch, the wood inside the FRP looked (and smelled) brand new. The principal failure had nothing to do with rot (although the top of the compression post itself was deteriorating significantly and would have caused a failure not too far into the future). The wood inside the beam was simply not strong enough. The 2x2x0.25 aluminum post I put in is good for roughly 30,000 lb, and is never going to rot.
Since so many people have written this up in great detail already, I decided I wouldn't bother unless someone was specifically interested. If anyone is, drop me a note and I'll send pictures and drawings.
I'm really pleased with the result, even though it took over four months to do it. Total cost was about CAD $800.
A comment about the original design: douglas fir has a compressive strength of only about 340 psi perpendicular to the grain. This means that the wood inside the original transverse beam directly above the compression post was not even capable of 5,000 pounds, which is nowhere near strong enough to support the mast on a boat of this size. Even though the beam on my boat crushed down between 1/4 and 1/2 an inch, the wood inside the FRP looked (and smelled) brand new. The principal failure had nothing to do with rot (although the top of the compression post itself was deteriorating significantly and would have caused a failure not too far into the future). The wood inside the beam was simply not strong enough. The 2x2x0.25 aluminum post I put in is good for roughly 30,000 lb, and is never going to rot.
Since so many people have written this up in great detail already, I decided I wouldn't bother unless someone was specifically interested. If anyone is, drop me a note and I'll send pictures and drawings.