compression post repair failure

Allan12210 · Jun 22, 2013

Splax,

At first I was confused. Now I see you have removed the side trim of the post, rather than the more typical door jamb piece. Take a look at my picture. So what you will see is that the post in your case only has solid support on the front side and that thin section is on the aft side where a lot of the mast weight and rigging load is supposed to be carried. On mine, there is solid material on the two sides of the post for front to rear support of the load. I don't think your previous owner did a very sound repair.

Ideally you probably should pull the mast anyway, but if you don't then my suggestion is to use a jack and temporary brace to support the beam (after loosening the rigging a bit to help de-load). Remove the post and reconstruct with a U-shaped post like mine that you can re clad with the teak. Don't use an L with the rest of your post as you want a more continuous solid piece with just enough channel for the wires.

While the post is out, inspect up in the hole for any problems. Its much easier (and I think better) to fix from underneath than going through the top. There is too much between the deck and the underneath to mess with including an aluminum plate glassed in. If the piece of transverse wood is up there still and starting to compress due to load or rot, you can cut just enough of the beam away (the area of the post contact) to cut the wood in half and shove it out of the way. (But by now you should remove the mast as you won't be able to support the beam with nothing inside to push against. In fact, the more I think about it, you should take the mast off anyway). Then use a solid block of aluminum with wire passage holes to form a solid couple from the underside of the deck to the bottom surface of the beam (4"x4"x the height). Once the newly fabricated post is back in place it will be covering 90% of the hole you cut in the beam skin which will be covered with a little piece of trim.

From my photos, you can see what that wood looks like in the overhead. You don't have to cut out anywhere as much as I did. Maybe your previous owner already took care of that, but the post is definitely not correct and band-aiding it won't last either. I'm surprised that the whole thing hasn't collapsed. Go ahead and do the entire repair all at once and be done with it. It doesn't take that long. With the mast off you can make sure the conduit for the wires passing through is well caulked to the deck to avoid leaks, the wire connectors are not all corroded (like mine were) and there is a drip loop in the wires where they go below the conduit, turn and go back up before entering the conduit so rain doesn't go in the boat.

Allan

Claude L.-Auger · Jun 23, 2013

Splax,
Allan gave you a very good explanation on the things to do to fix the problem once and for all. I totally agree with him that removing the mast is the safest and most advantageous way of doing a thorough and complete job. I have attached a pictorial on how I did it using a square 2" X 2" SS tubing. I did have access to a friend's machine shop which allowed me to do the machining myself. Don't hesitate to ask questions as lots of guys on the site have had to do it. Good luck with the project

heart of gold · Jun 23, 2013

The post you are looking for is in the mods section under "compression post repair from the top". It is a way to eliminate the wooden post by using a stainless pole and plate. It also avoids tearing into the beam saving a lot of interior work. When I contacted the Hunter Factory at the time I did this, they said "this is the way we construct all new boats" and gave me the green light. Good luck how ever you do it.

waternwaves · Jun 25, 2013

The more I looked at those two photos the more I was concerned.

The material the previous repair used does not seem to be appropriate. It looked like a softwood Fir/Hemlock type post, With all the of the moisture/expansion related issues possible, it seems to be a poor choice for that function on a glass boat.

Soft woods should be avoided in that possible damp location due to both moisture variance/expansion and temp issues with rot.

There is a reason that fir/hemlock has limited use on a boat.

metal or glass posts are a better bet, and bolt trim and furring wood onto them for show.

heart of gold · Jul 25, 2013

splax said:
Well, due to doors not closing and VHF transmission problems, I thought I might have a compression post problem. I took part of the trim off, it was held on with screws, and found what you see in the picture.
Apparently the previous repair has failed due to further degradation in the structure, causing the beam to twist aft. The interior you see is dry. I think that there must be an issue inside the fiberglass beam. I am interested to hear your suggestions on how to approach this issue.
Since it does not appear the fiberglass beam was modified previously, I want to leave it. I propose jacking the beam to release the force causing the thin piece of wood to bow and replacing the wood with a L shaped piece so there is more support and still space for the wires. Then, removing the mast and mast step, try to remediate the problems that I find there.
I remember someone writing about doing a compression post repair from the deck, but I haven't rediscovered it yet. Any help you may provide is appreciated. Thanks.

If you haven't started, take a look at my mod. If you are taking the mast down, this is the end all fix. Cheers, Ian

http://hunter.sailboatowners.com/in...mid=267&cat_id=31&aid=7802&page=article&mn=34

justsomeguy · Aug 2, 2013

splax said:
How do you measure the tension on the stays? I want to get this correct.

Via a tensiometer. There's one that sailors use called a Loos gauge, simple and stupidly expensive.

Claude L.-Auger · Mar 23, 2014

splax said:
Well, the compression post repair is done. It got warm enough yesterday to put the aft piece of trim on the aluminum post with construction adhesive. This is how it looks with the V-berth and head doors trimmed to close properly.

Looks good and with the aluminum post you used should last you years.

MY first one · Aug 23, 2019

I have found all these posts very informative and it has helped me begin the repairs on my compression post my 1984 H31. I have all the symptoms of the well documented failures of the compression post. Mine was rotted out through-out and very wet. Funny enough, the top beam is completely dry and not rotted. So here is my issue, what I found was that the top beam is dry and not rotted, water infiltration from passthru cable tube and compression post rotted but what I have found on my boat is the block of wood below the the post was soaked and rotted, I suspect that this partly gave way and the post dropped. I have not found any repair/replacement for this issue. I would require help and suggestions. The block of wood is placed so the grain of the wood is vertical and it is encased in some sort "basket" made from fibreglass (im guessing to keep it dry from the water from the head on it's way to the bilge). Has anyone done this repair also? I have attached some pictures.

Michael

heritage · Aug 23, 2019

My 1984 H27 had a very similar compression post to yours. It also had a rotted out post. A friend and I constructed a 2.5" stainless steel replacement. After the mast was removed, I used a hydraulic jack and 4x4 timber to raise the coach ceiling about an inch to make room to position the new post. I did not have the cracking that I see in your pics of the lower support area. Somehow you have to fix that before you go to the trouble of constructing a new post.

MikeHoncho · Aug 23, 2019

Nice work!

compression post repair failure

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