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Compression post misalignment

Short story:

Over 42 years and being sailed in heavy weather with the standing rigging improperly tensioned, the top of my compression post has shifted one half inch to starboard. As a result, the head door is out of alignment and barely closes. Everywhere I measure, (door latch, top of door, bottom of door) it seems *at most* one half inch at the top of the compression post is all that is required.

The post is not rotting at the bottom. The post is not sagging downward and there is no sign of deformity in the cabin top. The top of the post has simply slipped a bit and needs realignment.

Yesterday, I slacked way, way off on all the standing rigging to relieve the compressive forces on the post, and attempted to use a 4-ton hydraulic ram braced in the top of the doorway, to push the compression post (which is also attached to the port bulkhead) over. No luck.

Next, I placed the hydraulic ram vertically on the keel, and attempted to jack up the cabin top to relieve even more compressive forces, and tried to knock the post over. Again, no luck.

The problem is, I am unsure of how much force I can *safely* apply before blowing something apart. I was being pretty conservative with the ram.

I could use some advice. I know that Jeff H. and Rich H. are usually pretty good at this stuff.
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Re: Compression post misalignment

Take the door off and get a planer and make it fit. The boat has been sailing for 40 years just fine, NO? Properly tension the rigging and see if it will come back into alignment, with, natural forces....
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Re: Compression post misalignment

I have properly tensioned the rigging with a Loos gauge.
While this did not bring the post back into alignment, it did stop it from moving further.

Yeah, I could plane the door and more the striker plate but I was wondering about a more complete repair.
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Re: Compression post misalignment

I guess I would start by asking a couple questions such as:

What makes you think that the compression post has moved? The clues as to why it moved may also hold the clues as to why it won't move back.

Do you have any pictures that you can post?

Are there signs that anything else has shifted?

Could the boat have been constructed that way?
Pearson was not always all that great at precision building. I helped a guy replace a rotted bulkhead on a P-26. When the old bulkhead and some of the bunk parts were removed there were a series of paired marks in two lines on the hull that were labeled 'blkhd'. The bulkhead sat against a fiberglass bunk base and was aligned with the far side of the marks and completely outside of the pair of marks which appeared to be where it was supposed to be located. What we did not know was whether the bulkhead was in the wrong position or the marks were in the wrong position, or perhaps we were misinterpreting the marks but either of the first two suggested a questionable layout procedure.

In any event, I would be careful about applying too much force until you figure out what had caused the post to move. The fact that you could not move it suggests that it may actually be structurally okay in its current position.

Jeff
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Last edited by Jeff_H; 3 Weeks Ago at 09:35 AM.
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Re: Compression post misalignment

Maybe 40 more years of hard sailing will bring it back? Did you notice any difference in speed or performance on one tack or the other? Possible that the hull has been deformed as well? Any difference now that you've got the rig better tensioned sailing performance wise?
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Re: Compression post misalignment

Bulkhead tangs cracked or broken?
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Re: Compression post misalignment

Is the door issue the only evidence that things have moved, or can you see the original location of the post against the overhead or liner?

Is the bulkhead 'dadoed' into the post? or is the post attached to the face? Is there any evidence of the post and the bulkhead itself having moved relative to each other? or together as one?

Could be the boat has 'racked' over time and the entire bulkhead post assembly been somehow 'displaced'.....?
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Re: Compression post misalignment

Bulkhead tabbing doesn't *appear* to be broken.
Boat sails evenly on each tack. The entire boat isn't warped.

Jeff:

I agree that Pearson wasn't very precise, especially on the early boats.

Why I think the post shifted:
When I bought the boat, the head door closed without too much fuss, but the latch still didn't line up.

Before I had a better understanding of rig tuning, I sailed the boat with sloppy rigging in some pretty snotty weather. The post seemed to shift 1/8th to 1/4 of an inch more, and then door refused to close at all.

I think the shock loading of the rigging while sailing, caused the mast to "float" at times, allowing the compression post to slip. I have since replaced ALL of the standing rigging, and put it under proper tension. Since the mast can't "float" anymore, the post has stopped moving.

Sorry, I can't post photos from work, but I can email them to you.

What else may have shifted:
On the port bulkhead, there is a pencil mark from the factory, traced along the cabin liner. It is now 1/2 of an inch or so, away from the cabin liner. I'm betting that this pencil mark was not quite visible when the bulkhead (and compression post) were in their proper location.
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Re: Compression post misalignment

I don't know how your 30 is set up, but I, like Jeff, have also replaced the compression posts and mast support crossbeam on my P26. I don't know if any of this will be of any use, but here goes anyway..

On the 26, there's a big crossbeam supported by two compression posts, with the one to port being much closer to the mast/center of the boat and therefore supporting most of the weight. On my boat, the crossbeam had almost completely rotted and, while the compression posts were still in fairly solid condition, the main one had shifted downward, bending all of the screws that attached the bulkhead to it and it to the interior of of the foremost dinette locker. The PO's solution was to remove the door because, obviously, it no longer shut, and replace it with a curtain. Solved! sheeeeeesh.... of course, the mast wasn't really supported by anything other than the deck at this point, but hey, what did he care, right?

Because the screws were so bent and damaged, it was a nightmare to remove; required a lot of grinding. I know... too much info, and may or not have any bearing on your issue...

I learned that the MAIN reason that post shifted downward was not a deformation of the deck or crossbeam, but the fact that the wedge that was supposed to support the BOTTOM of that compression post against the keel was missing. On the P26, the compression post rests on a fiberglass tang built into the sole, but there's supposed to be a wedge under that tang to couple the load to the keel. There wasnt' one on mine, so the whole thing shifted down about 1/2". I replaced both compression posts, the crossbeam, built an apppropriately-sized wedge (white oak in several coats of epoxy), dug out and filled all of the mast step mounting holes with epoxy, redrilled, and put it all back together. It's been perfectly solid and immovable for two years.

You mentioned that your compression post had shifted 1/2" sideways. Are you sure? Is it possible it shifted downward and that's what's causing your door binding issue? Is the base of your post solidly resting on a support?

Just thinking out loud.. I really have no idea what I'm talking about.

Barry
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Re: Compression post misalignment

No problem, Barry.

Unfortunately, our boats have a different system.
There is no crossbeam, only the port/stbd bulkheads and an overhead cabin liner.
The compression post fits into sort of a socket in the cabin liner. The socket is larger than need be, and allows the top of the post some movement to be in proper alignment.

The foot of the post simply sits in the forward bilge, on a built-up hump of fiberglass.
If the bilge is allowed to remain full all the time, the foot of the post can rot.
Symptoms are: a "dish" in the deck around the mast, and visible sinking of the post.

My post is exhibiting a more lateral move to starboard, and ONLY the top of the post.
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