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Dear folks
When I had my boat surveyed prior to purchase, the surveyor noticed an indentation in the deck area around the mast. Below decks, the door to the head would not close. Recently I had the mast removed to inspect the rigging, etc. and the deck redressed itself and the door will close. Now the yard has put the mast back on and all was well until they tighten up the rigging screws and, sure enough, the door will not close!!!
So...something gives. It would seem that there is compression of some sort at the bottom of the mast support. They are investigating now, but I wonder if anyone else has had similar issues. What does the mast support rest on? Could the bottom of that support have become soft due to water over the 40 years since construction?
I was intending to just leave it alone, shave the top of the loo's door and hope for the best, but with the mast off I thought it should be investigated.
Thoughts? Comments?
Many thanks in advance.
Bob
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So you should look at the base of the compression post under the floor of the boat. sounds like you have some rot in it and it is compressing with the mast up. Probably should fix that. If it compressed a lot say in a storm it could cause slack in the rigging that could allow your mast to do bad things. Not to mention it is damaging the deck under the mast. This is a semi common issue. All our boats have a teak compression post that acts as the corner of the the forward bulkhead. so it is between the bulkhead and the door. I had looked at ours once 🙂 and it look like someone had repaired ours at some point in the past. Though teak is a great wood over time it will rot sometimes if left wet to much. Causes are water from anchor locker running length of boat to bilge and wetting base of post where it sits on keel or water following wiring in mast down through deck and keeping it damp in there.
Common fixes include total replacement of compression post which is pretty serious as it is also corner of head. It's a lot of expensive teak and craftsmanship to replace 🙂 A few have used the existing box beam structure and put a heavy stainless pole with flat stainless plates top an bottom that go under the deck and on the keel that runs up through the center of existing compression post to offload the teak taking the stress anymore.
Next and most done is cutting off rotten bottom and building up solid fiberglass base on keel to keep water for hitting it and then using solid fiberglass or metal built up between that and base of post to give it a support to sit on again.
Make sure however you do it that it is designed so that if water does follow wiring in future down through deck it can't pool at base and leave wood sitting in damp. Instead give it easy method of draining to bilge.
Third make sure wiring is sealed so water can't get below decks following it. put in drip loop or something to make it drain out from under mast on deck not through deck.
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just a note... it is the door sticking that is making me think the bottom of compression post is rotting rather than the core in the deck giving way. If it was just core in the deck then it shouldn't affect the door. door sticking tells me the floor is actually deflecting down there at the corner. This would be the weight of the compresson on the mast pushing the deck down which pushes the corner an bulkhead down which pushes the floor down. for all that to happen the bottom of the compression post has to be squishing and compressing so it is no longer as long. ie.. rot.
Scott
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Ugh! Sounds dreadful, but your logic about the door to the head not closing is exactly what I have been thinking. However, if the compression post is rotten at the base would you expect it to spring up when the mast is taken off? I'll have to get over there on Monday and crawl around to scope out the problem. Are there any drawings of the details at that point? Would be useful.
Thanks for your insights. I'll let you know what I find out.
Bob
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No drawings that I remember.
and yes I would expect it to spring up when you take the mast off. The compression of the mast is pushing down on the cabin top and the floor inside the boat. Both of these will want to spring back some when you take that weight off them.
good luck.. it is a tight space under there. Doable but not fun at all. You might need help wiggling back out once in. I think you have to go down in the hatch vberth and then sort of crawl back about 4 or 5 feet to get to it. I have done stuff with the drain on the floor of the head which is about 2.5 feet closer and it wasn't fun. Not as bad as crawling into the engine compartment for me but still bad. Having someone else to help you out and hand you stuff while your in there working is going to be needed I think. You should be able to with a flashlight just be able to stick your head in and see it. Take a good camera or cell phone camera and get a few really good High resolution pics you can blow up on a big monitor to look at. Really bright flash light so you can see well and get good pictures. Also maybe take a long stick or something with a nail or other sharp object on the end that you can poke the bottom of the compression post with from the hatch. .. if it sinks in you know its bad bad.
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I went over to the boat yard this morning, took some photos and discussed with the boat yard's owner.
I did this before reading your post so did not think to poke into the wood, but the owner assured me that it is soft at the bottom.
The attached photo shows some strange features. First, the support post is not vertical. It seems that the original compression post has been cut off about 3 inches below the floor above and a new section added and glassed in. Can you comment on this? Does it look "original" to you? Second it seems that there is a "new" piece below what looks to be the original post. This suggests a prior repair for a similar incident earlier in the boat's life. I'll ask the original owner if he recalls such a repair.
In any case, the boat yard man proposes to cut out the middle section and replace it with a stainless steel support made up of two "cups", one fit to end of each post with a screw jack in between. Once the mechanism is in place the screw will be turned to push the original support back into its proper position. This seems like a sensible solution with out a huge amount of work. Yes, its very cramped down there, but it does seem "doable".
Any thoughts or comments will be greatly appreciated.
Bob
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Sorry it has taken a few days to bet back on this. We got to do a free mini vacation so I have been not checking email as much or following the forums. 🙂 it was nice to relax a little.
ok... I have never heard of that method of doing this but it sounds good.It would not just need to be cupped around the post and a bottom post? but physically bolted to them both I would think. At least for a worst case scenario of the boat is knocked down or rolls. I could see the mast pumping and maybe deck rising and pulling cup up and it falling out or twisting? This is just out of the box thinking. Ideally you have a single long post from bottom of deck to keel. Honestly though given limited resources I would would probably do this.
Not sure you couldn't open up hollow box beam in corner of head with removable section inside head and slide a full stainless post in there with stainless flanges on top and bottom. Have it cut in half so you can get top and bottom in with a 12 inch to 24 inch slip joint section it slides into top and bottom and once in place and deck lifted to correct height you weld and bolt it all together.
You could also do something similar with a threaded section to adjust tension on this also.
How about some of our other owners brainstorm on this and share your thoughts. I have already learned something new and I'm sure there are other good ideas out there.
Looking at the picture it looks like they glassed the bottom in place but then didn't drill drain holes at the bottom of the wood post. The created a fiberglass cup that held water against the bottom of the post. If doing the steel cup jack idea make sure the upper steel cup that goes around the remaining post has drain holes in it so this doesn't repeat itself with the new setup.
Scott
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Thanks, Scott. Glad you got a well deserved holiday. Best to take these when the opportunities present themselves. Carpe Diem!
The plan is still essentially as I described it earlier, except that the whole "new" section has been removed and instead of a cup at the bottom it will be a flat plate epoxy glued to the fiberglass floor. I do like the idea of fastening the upper cup to the bottom of the wood post for the reasons you mention.
Another point which I did not mention before is that the screw jack itself will have a double nut to keep it from unscrewing with the twists and turns of the boat.
I'll get some pictures of the parts before installing and after its all in to share.
All the best
Bob
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Had similar problem 20 yrs ago and tried to lift deck and put a large beam over doorway. Could not come up with reason for sag in deck other than the compression post was too short. The floor step under the post inside the boat was not distorted and the short post under the floor was not rotten. The foam core in deck did not seem compressed. Did not have any loose standing rigging. I still put in this beam and marked with pencil to show any distortion. To this day these marks have stayed the same except for one mark that has dropped about 1/16 inch. My gut feeling is that all my work was for nothing. The best test would be if your standing rigging starts to get loose. If it does not, I would just monitor the situation with a lot of pencil marks.
Cheers and beers,
Jim
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