compression post

  • June 10, 2019 2:07 PM
    Message # 7571079
    Deleted user

    I went to tune my rig and noticed that everything was looser than it should have been and the forstay and backstay turnbuckles are approaching max adjustment.  This led to pulling the water tanks and inspecting where the compression post meets the keel.

    After poking around a bit, this is what I've deducted.  There is a solid 3.5x2" floor joist ruining under the aft half of the compression post.  There are three large stainless bolts going through the joist on the port side and it looks like they are passing through the bottom of the main cabin bulkhead on the forward side of the joist.  Below all this, at the floor of the bilge, is a 4x6" block running athwartships which has been epoxied to the hull..  I guess I will call this piece the bilge block? 

    Sitting on top of the bilge block, behind (forward of..) the floor joist is a small block of rotten wood which I'm assuming runs between the bottom of the compression post and the top of the bilge block.  

    Since my access is pretty limited, and I cant really see much of whats happening behind the floor joist, my current plan is to take the sawzall to the floor joist and cut out a 6" section directly under the compression post.  Then ill remove the rotten block of wood.  Add another block of wood to the bilge block, doubling its width so it supports the compression post completely.  Then insert a fresh epoxy sealed block of wood between the bottom of the compression post and the bilge block and lastly, wedging in some marine ply between the floor joist and bilge block to support it across the section I removed.  

    My only real concern here is that I'm cutting the floor joist, which looks to be part of the bulkhead support, into two pieces.  My rationale for this being ok is that the compression post is now directly supported down to the bilge, not just half supported by a small block, and both sides of the cut floor joist will also be supported down to the bilge as well.  Laminating a new floor joist up against the old one and passing longer bolts through the bulkhead and some on the starboard side to tie it all together crossed my mind but it could also be overkill.  Also drilling the holes and getting access to the far side of the bolts would be a challenge.  

    Any thoughts/opinions would be much appreciated as I would like this to be a solid and efficient repair, while avoiding pulling up the floor or opening up more than I need too.  Cutting out the shower pan could open up some more access but I would prefer not too.

    Also opinions on what wood would be best.  Using starboard or some other composite is definitely a consideration.   

    I'll upload some photos shortly...

    Last modified: June 10, 2019 3:36 PM | Deleted user
  • June 10, 2019 3:35 PM
    Reply # 7571197 on 7571079
    Deleted user

    Heres a photo.

    Floor joist at the top.  Bilge block at the bottom.  Soft block in the middle back.  Theres no visible deformation of the cabin top and it doesn't look as things have shifted significantly, though there is definitely some bad wood in there and now that I'm this deep I might as well sort it out.  The bilge was flooded to the brim with water and diesel for at least 2 years.

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    Last modified: June 10, 2019 3:37 PM | Deleted user
  • June 11, 2019 2:45 PM
    Reply # 7573163 on 7571079

    Please go to my Westsail Service Manual, Page A-19 Mast support problem on Westsail 32, and it should explain what is happening, and the fix.  You can find the Manual on my website,, if you do not already have a copy.

  • June 12, 2019 10:24 PM
    Reply # 7576884 on 7571079
    Deleted user

    I have read the manual and also a few other posts on the repair.  My boat was a kit boat and it does not look to have the same configuration near the keel as other photos I've seen.  The deck beams seem far too thin to put carriage bolts through. Perhaps I need add some material there.  

    What wood is preferred for blocking down to the keel?

    Last modified: June 13, 2019 1:30 PM | Deleted user
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