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post #1 of 13 Old 10-04-2009 Thread Starter
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Compression Post Blues

Sailors,
I would like to discuss a possible mast compression problem with people who have been there, done that, and have the t-shirt.

I am looking at a Southern Cross 31 with lots of deck crazing, cracking around stanchions etc. A survey has turned up no concerns about deck or hull integrity. My concern is the apparent slight crushing or dishing of the cabin top in the area of the mast step. Also, there are parallel cracks in the fiberglass surface where the cabin top meets the deck in the area of the mast.

The survey did not determine a reason for the dishing. The surveyor looked but did not observe a compression post problem.

First, does deck dishing around the mast step indicate a serious problem?

If so, might hidden compression post problems exist that require disassembly for observation? What parts of mast removal and compression post disassembly require yard expertise and what can be done by a do-it-yourselfer? What $ values might be assigned to different repair scenarios?

Any light you can shed is greatly appreciated.

Jim Lavery

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post #2 of 13 Old 10-04-2009
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Lavery, I would post this question over at Brion Toss's site.

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Last edited by jmolan; 10-04-2009 at 08:04 PM.
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post #3 of 13 Old 10-04-2009 Thread Starter
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Thank you Jack. I'll do it.

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post #4 of 13 Old 10-04-2009
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lavery over at sailboatowners.com there are also some post replacement right ups there too. they may not be for your boat but they can still help
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post #5 of 13 Old 10-04-2009 Thread Starter
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Thank you Scottyt - I'll head over there right now.

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post #6 of 13 Old 10-04-2009
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Quote:
Originally Posted by lavery View Post
Thank you Scottyt - I'll head over there right now.
i just looked... if you do a search on compression post you will get 4 pages of results. it will cover all boat types.
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post #7 of 13 Old 10-05-2009
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It's not a rigging problem, but a structural problem. Whatever post/bulkhead or beam that is designed to support the mast in the Southern Cross is failing. Find out what method was used by investigation. Sometimes there is a block under the cabin sole and if wood it can rot over time allowing the post to sink slightly. Sometimes the beam under the cabin top will sag. When you know how it was designed and built you can plan for a fix. Until then you are just guessing.
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post #8 of 13 Old 10-05-2009
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Quote:
Originally Posted by mitiempo View Post
It's not a rigging problem, but a structural problem. Whatever post/bulkhead or beam that is designed to support the mast in the Southern Cross is failing. Find out what method was used by investigation. Sometimes there is a block under the cabin sole and if wood it can rot over time allowing the post to sink slightly. Sometimes the beam under the cabin top will sag. When you know how it was designed and built you can plan for a fix. Until then you are just guessing.
Brian
Agreed..Its either in the deck core or the post top or post base or what the post sits on above the keel. It ain't rocket science figuring it out... that's not meant meanly by the way....just check all the options and you will find the culprit.

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I tried to research how the mast is supported but got nowhere on the web. I did find an original brochure on the 28 http://www.msogphotosite.com/MSOG/pd...cross28bro.pdf , but doesn't mention the mast support.
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Here's a drawing of the layout showing what looks like a vertical post just to port of the head. I do know that some of these hulls were sold for owner completion so your interior may not be the same. If it is I think either the deck is crushed under the mast or the post's support under the floorboards may have issues. But I don't think the post could move much without affecting the bulkhead/door arrangement. If it moved the door(s) would not fit properly.
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