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Old 24-11-2012, 08:40   #1
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Compression Post Rot

We've determined that the rot spreads ~ 2 " up the post from the bilge. The rest of the post appears fine inside and out. There is no warping or visible distortion of its seat on the keel, however it is only a matter of time.

Would a fix be to sure-up the post with 2x4's, cut out the damaged section and replace it? (Or leave the 2x4's in place).

This a bottom up problem with no deck leakage or distortion and I will not be able to take the boat out for a full replacement.
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Old 24-11-2012, 09:18   #2
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Re: Compression Post Rot

Quote:
Originally Posted by Adjsut View Post
We've determined that the rot spreads ~ 2 " up the post from the bilge. The rest of the post appears fine inside and out. There is no warping or visible distortion of its seat on the keel, however it is only a matter of time.

Would a fix be to sure-up the post with 2x4's, cut out the damaged section and replace it? (Or leave the 2x4's in place).

This a bottom up problem with no deck leakage or distortion and I will not be able to take the boat out for a full replacement.

What is the compression post made of? Solid wood? Hollow? What type of wood? A picture would help of the post and the base. You should also check the coring of the deck above to be certain there is no delamination. A deck may appear sound, but the core material could be damaged or compromised. If the post is solid, a splice could be acceptable if properly fitted/mated and could be installed without removing the post above with some 2x4's and a couple house jacks to keep the deck properly positioned during the installation. Also, it might help to seal the base of the post in fiberglass to prevent water from rotting the new structure. A few coats of good marine paint will seal the glass. I would not use 2x4's in the base even if they are treated. Good luck.
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Old 24-11-2012, 11:32   #3
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Re: Compression Post Rot

I've experience this in a different boat. I replaced my entire compression post with starting from the top of the keel in the bilge with a solid block of teak, then a solid 2x8 piece of teak spanning two floors, then a stainless 4x4 square tube to under the cabin top. What I imagine you would want to do is just part of what I did by cutting out the bottom 2" plus and adding a solid block of teak or non-compressable plastic, or non-corrosive metal, held in place by shoring or fiberglass.
I used a hydraulic bottle jack to get clearance enough to install the compression post. Don't over do the jacking.
Good luck in your repair.
kind regards,
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Old 24-11-2012, 14:50   #4
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Re: Compression Post Rot

Don't forget to slack off your rigging before you jack up the deck.

When you have the compression post out take a very close look at the mounting structure at the keel. Many builders used wood encased in FG and often they need rebuilding. You may be able to do something about drainage to keep the bottom of the post dry so you don't get the same problem again.
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Old 24-11-2012, 14:59   #5
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Re: Compression Post Rot

Would it be possible to cut off the bad wood and use a block of Marelon (Sp??) the black plastic like stuff that can be machined and make a socket with the added height to compensate for the wood that gets removed and eliminate the continued threat of rot from the bilges. I am not sure of the compression loading for this material, I imagine it wouldn't be too hard to suss out.
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Old 24-11-2012, 17:25   #6
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Re: Compression Post Rot

Quote:
Originally Posted by DeepFrz View Post
Don't forget to slack off your rigging before you jack up the deck.
^^^^^^^^^^ +1^^^^^^^^^^

FWIW, I'd screw two opposing blocks on each side of the comp post and work two short pieces of shoring at a 45 angle from each side resting on dunnage across the stringers (or bare hull)... the idea being to displace the load over a large area... think a "peace" symbol for the design.

Quote:
use a block of Marelon
I have a big ass block of it... how much you need? I'm 45 miles south of you!
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Old 24-11-2012, 19:47   #7
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Re: Compression Post Rot

Yes on the marelon. You could build up layers of fiberglass stretching up the sides of the hull in the bilge too but its a lot of work down in there.
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Old 24-11-2012, 20:22   #8
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Re: Compression Post Rot

I'll have images up soon, as i'm currently traveling.

Thanks for the input - it will definitely guide me in finding the safest way for replacement.

One note from memory:

The compression post does not sit in a mounting on the keel (the area does appear to be reinforced with Fb however).

As I understand it reinforcement was built a little ways up the side of the hull parallel to the keel. From these two parallel rays a solid flange (finger) extends which connects with the post about 5" above the bottom of the bilge.
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