Mast Compression Post – Westsail 32 – Inspection and Replacement

Mast Compression Post – Westsail 32 – Inspection and Replacement

The mast compression post has been of concern for some time now. The overriding evidence that there may be a problem occurred the first time we tightened down the rig for open water sailing. The door to the head compartment became misaligned to the point that the barrel lock would not work properly. The doors were also jamming tight against one another. I surmised that something had to be moving and it seemed logical that the something was the compression post. Mary Rose has had the recommended update to the aft mid-ship bulkhead for added strength so I was not terribly concerned about any major failures. We lossened the rig and we were ready to proceed.

I was hoping to be able to inspect and fix the problem by gaining access from the shower pan side of the bulkhead. This would require cutting the bottom of the shower pan out. I was planning on doing this anyway to be able to store additional anchor chain low and mid ship. However I soon realized that it would be much quicker to drain the forward water tank, pull it out of the bilge and fix the compression post.

Draining the tank and removing it took less than 30 minutes and we were ready to tackle the problem. It was easy to see that the wood supporting the mast support post was showing signs of rot and was soft at the base. Under the mast support post there was a bulkhead that went across the bilge from each side of the hull. Below this bulk head was very soft and black piece of wood that extended from the keel to the bottom of this bulkhead. There was a large block of wood approximately 3 inches thick and 5 inches wide that was screwed into this bulkhead and extended from the keel to the mast beam at the under side of the cabin sole.

All of the old support pieces were removed and discarded and we were ready to begin the repair. I made up a couple of believable reasons why I had to go get supplies to finish the project and went ashore. The Admiral stayed aboard and took advantage of the water tank being out of the bilge and proceeded to clean and sanitize the bilge in the area of the forward water tank. She did a great job and her efforts had a huge impact on the overall project.

I cut two ¾ inch starboard pieces to the exact thickness of the area under the bulkhead and drove them into place for a very tight fit. I used a thick knife blade to shave them to the exact size. The knife blade was used as a draw blade. After they were firmly set in place, they were screwed them together so that they could not separate in the future.

The next step required placing a two pieces of blood wood to fit the exact distance from the keel to the base of the cabin sole on the forward side of the keel supported bulkhead directly under the mast support post. I placed a ¼ inch thick piece of brass plate on the bottom next to the keel to prevent future rot problems from keel/bilge moisture. I drove the first piece of blood wood into place and screwed it to the starboard support and the keel bulkhead. This locked all three parts of the mast compression support into place. Starboard block, bulkhead, post support.

The next step was to drive the second piece of blood wood into place for a tight fit and add additional screws to prevent any chance of the supports sliding out of place.
The final step was to use some minute mend two part epoxy to bond the brass plate and wood support pieces together with the keel to further reduce the chances of any future movement. Yes, I know this was a bit of overkill but I really do not want to ever have to do this project again.

We taped cross cut sections of 4" vinyl hose to the bottom of the water tanks to keep them off the bottom of the keel and allow water movement in the event we get water in the bilge.

We then replaced the water tanks into the shiny clean bilge and the project was complete. The entire project took about 4 hours and cost less than $25. We used blood wood because it is extremely hard and rot resistant along with several other qualities. Boat builders used blood wood for motor mounts a very long time ago.