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T O P I C R E V I E W
Chichester
Posted - 04/22/2023 : 10:49:17 Hi all, I am looking for some insight, previous posts, on replacing the 1981 C25 mast compression post/block. (The block of wood under the post mast step support post.) Thanks
6 L A T E S T R E P L I E S (Newest First)
sefoiler
Posted - 02/12/2024 : 21:07:54 Fixed keel owner here with some rot at the bottom of my compression post block. Any insights into repair/replace appreciated.
Lee Panza
Posted - 06/10/2023 : 07:55:09 Just realized how long it's been since I've checked here. However, Chichester, if you're still concerned about this I have some info to pass along that could be quite relevant. However, I've got a swinger, and I'm not 100% certain it would be the same for a fixed keel (I suspect that, in most respects, it would be).
The swing-keel Cat25 is entirely different from the 30 in this respect. The hull is gently rounded - almost flat - in this area, so there was no need for Catalina to provide a tapered block there. I had installed an inspection port in the sole next to this spot, and I have a photo of the area in question. Evidently, the structure between the wood compression post and the area just above the inner surface of the hull is just fiberglass; it's an integral part of the cabin liner assembly. Between this and the hull itself, Catalina apparently just piled a mound of a purple-colored resin that hardened after the inner cabin assembly was lowered into the hull assembly. The excess squeezed out, and this allowed for an imprecise tolerance between the cabin assembly and the hull. I can post pictures to clarify this if you're still interested.
Voyager
Posted - 04/26/2023 : 05:28:09 Looking at the mast compression post base block in the photo it appears to be a nice solid piece and I see how it could fit underneath the compression post and rest on the keel. Being made of wood, however, it seems like it would quickly be attacked by wetness in the bilge, be it from rainwater or seawater. I think that I’d try to do something to add a wood preservative, either some kind of paint or resin products, but I don’t really have any idea about what kind of coatings to use other than creosote (which is toxic and nasty). That’s what they used to coat telephone and utility poles with to prevent rot. I’d probably try to figure out how to take all the downward force off the post and perhaps jack up the cabin top a few mm to somehow remove the old compression post. You’re right, it’s best to talk to someone who has actually done the job before. They’d have the most accurate and informed perspective on the job.
Voyager
Posted - 04/24/2023 : 17:08:33 Which cabin layout do you have? I have a dinette style that provides access to the bilge and underneath the compression post. The two other cabin layouts (2 settees and a drop down table) and the third layout doesn’t make it so easy to access the bilge. Good luck if you have to deal with this.
Chichester
Posted - 04/24/2023 : 10:51:12 Hi Voyager,
Thank you for your input. so, the block I'm referring to is situated under the sole at the very base of the mast compression post, in the bilge.
After a great deal of searching, it seems the terminology for this component differs from place to place. E.G. If I search C25 compression post block without clearing out search history, I end up with an array of blocks and pulleys. Some call it compression block, others call it bilge block.
The challenge is to find someone who has actually carried out this repair, preferably without tearing up the sole....if you see what I mean.
Cheers
Voyager
Posted - 04/22/2023 : 20:21:57 The block is embedded in the top of the cabin fiberglass and could be made of a hardwood or teak. That block sits atop the mast compression post that spans between the keel (on the bottom) and the underside of the cabin top directly underneath the mast. If my tabernacle block had deteriorated from age or rot, I’d consider replacing it with a block of pressure treated lumber, typically southern yellow pine, or several layers of pressure treated plywood sandwiched together.
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.