Compression post surgery

Scott · Nov 21, 2011

You are correct that the transverse beam above the compression post is rotted. When I have more time I will post some pictures of our repair.

Steve Dion · Nov 23, 2011

Jared:

There are some photos of the H'34 with a beam repair. You may want to look that up.

kloudie1 · Nov 23, 2011

Mast Support Beam

Jared, I did mine without taking the mast off, and I am sorry I did it that way because I couldn't fully address the wire conduit, where the leak is that is responsible for the rot. I replaced the block under the mast with a block of solid aluminum that I had machined to go up in there with all the wires and the tube stub in place. That is the block sitting on the table. The other picture is of the cut in the beam where the rotted stuff was removed. I drew a line around the post before removal and made a cut after the post was removed so that no glass work had to be done. The post bears on the aluminum block now. Last picture is the finished job.. Can be done without removing the mast, but you'll have to remove it later to address the wire run. A vibrating "multi-tool" is the perfect tool for this job..

lnikl · Nov 24, 2011

With the possible exception of early production H34, compression post problems are an issue on H34s as well (very similar boat to the 31). There is a very good solution to this problem posted on the H34 Owner Mods by Ian. I would suggest that you check it out. http://hunter.sailboatowners.com/in...mid=267&cat_id=31&aid=7802&page=article&mn=34

Scott · Nov 24, 2011

compression post repair

Hope these pics help. Couldn't get them in order - sorry.
Long story short. Had a reputable yard perform first fix, thought it was permanent (~$1,700). Several years later had leak and buckling of bulkhead head again. Removed trim aft of post and trim along the underside of the transverse beam the yard installed and found the deflected fiberglass, galvanized CP, and rotted wood within the beam.

The yard had fabricated a 1-7/8" square post with 2" plates welded on each end of X? length. Don't know how they came up with the length.

We then loosened the shrouds, jacked up the coach top, and made the repair. Like Kloudie, we had an aluminum block made with a slot for the wiring. We slathered the plate and bottom the aluminum embedded mast base plate with West System epoxy and placed the alum. block (2"x2" 1-3/4"). Fortunately, the yard had a hole drilled in the top plate through which the wiring was led, therefore unlike Kloudie, we were able make the repair relatively easy. Let it cure and removed the jack. No movement and now a permanant fix.:dance:
As far as the bulkhead repair, we simply routed out 2 plys of plywood in the damaged area and used contact cement to lay in some masonite. Still have to do the glass work. Hope this helps and if you want more info, let me know.

Mike Culik · Dec 17, 2011

Thank you Claude and Scott for your information.

Yesterday, I confirmed what I expected and have significant compression post rot on my (new to me) 1986 Hunter 31

After removing the door jam trim I found 2 to 3 inches of the post disintegrated as well as the lower bulkhead wood. Additionally it looks like there is 2 to 3 inches at the cross beam rotted also.

I haven’t removed the post yet to see if the cross beam itself is rotted, what should I expect.

In your repairs, does the aluminum block replace what was removed of the cross bream?

The boat is in the water with the mast up and I plan to loosen the shrouds and jack the beam up to replace the post.

Does the bulkhead provide and structural support?

Any additional detail or pictures (removal of the cross beam) of your repairs would be great.

Thank You, Mike

PS… I’m really liking the boat even with the work!

kloudie1 · Dec 18, 2011

Compression Post

Mike, The beam is a fiberglass channel filled with fir 2X4. The mast base wire tube leaks and the wood rots and collapses. The beam itself is not strong enough to support the mast loads. The bulkhead should not do any structural support, but as the post and beam collapse, it picks up some load. The aluminum block takes the place of the collapsed wood under the mast step and the little layer of glass that the post used to bear on. Pictures attached are: rotted wood under mast base; Struts (pink wood) holding the aluminum block for epoxy to set; jacking rig to get post out after loosening the rigging.

Scott · Dec 19, 2011

In your repairs, does the aluminum block replace what was removed of the cross bream? - Yes

Does the bulkhead provide and structural support? - No

Any additional detail or pictures (removal of the cross beam) of your repairs would be great. - Sorry no.

We used a Demel multi-max to cut the fiberglass to expose the rotted wood and "hogged" it out with chisel, srewdriver, etc. in the cross member.

Be certain to remove all rotted wood and fiberglass to the underside of the aluminum mast base plate to ensure a solid surface.

Mike Culik · Dec 19, 2011

Thanks Claude, Scott and other previous posters….
Your words of encouragement sure help this “newbie”

My Plan is: with mast stepped but shrouds loosened
1. Jack up and support the cross beam
2. Remove the remaining support trim
3. Mark the cross beam where the compression support is
4. Remove the rotted compression post
5. Cut the cross beam fiberglass with a vibrating multi-tool (picked one up from our local Harbor Freight today)
6. Remove the remaining cross beam timber and what ever else is up there …
7. Manufacture a replacement compression post out of:
a. Pressure treated wood? Easy and cheap-may only last as long as the OEM (1986 hum 25 more years)
b. Stainless pipe? Expensive and time consuming to get done
c. Other ideas?
8. Install new post and trim out etc.

Questions:

1 Why did you use an aluminum block spacer in the beam hole vs. just running the replacement post all the way up?

2. is there a critical height measurement – I am planning on extracting that from the post/trim remains

Anyway, I sure appreciate any and all comments and advice and hope to tackle this as a Christmas present

PS. the boat is in the water (bubbled) and I have dock power, thus heat with my ceramic disc heater YEA!

HAPPY HOLIDAYS TO ALL………… Mike

kloudie1 · Dec 19, 2011

I used a Harbor Freight Multitool.. Excellent for this job.. Worth every bit of the $19 that they cost today.
1. Original post was fine except for a little rot in the first 2".. Teak was all fine.. so I routed out the top and replaced with oak, then treated all the internals with the green preservative (copper naphtenate).. Wanted to keep the fine looking teak post so put a spacer in there.. I thought about pressure treated wood too but it dries and compresses a lot ! .. I wouldn't go there.. The vertical load from the mast is pretty big.. a coupla tons.. Ya really don't want any "spring" in the mast base support.
2. I don't think the measurement is REALLY critical but I would put it within half an inch of where it is now.. When I pulled my post, it had written on it "34" and a measurement, "70" .. May be different on the 31, so don't use that number. but when I measured the post it was exactly 70" Note that you can still see the "70"" in the first photo on the end in the right bottom corner.

Scott · Dec 19, 2011

Mike,

Kloudie was lucky finding the dimension. I contacted Hunter about the post dimension. Told them we jacked uo the coach top to provide positive drainage. They could (would) not provide the number, but were kind enough to suggest jacking it another 1/4 to 1/2". Everything seems fine now. Keep at it, you'll get there!

Ed Schenck · Dec 19, 2011

What I see is a DeWalt saw. I had to sell mine when I moved to the condo. Sure miss that saw. Really do like your fix. Hope it ends up in the Mods forum with more pictures. Hope Brian is watching.

Oh, and that heavy box that was delivered and I am not allowed to open? I think it might be the Bosch version of your MF tool. I can hope.

BillyK · Dec 20, 2011

Jared1048 said:
I've been kicking around different ideas on how to fix this and finally took some action. Placing a jack next to it was able to relieve the pressure on it (after slacking the stantions first) and remove the door jam cover to inspect for rot. To my suprise I didnt find anything. Top or bottom of post looked good to me. Nothing like some other pictures I've seen.

Now what i did see is that pressure from the mast has leaned forward on the bathroom wall and causing it to buckle. I can only assume this is because of the cross beam giving about a half inch.

What to do?!
-Jared

Why in the world did they use plywood for compression!? :-/ I'm going through the same repair on my Catalina bilge block where they used ply.. At least the compression post was solid teak.. I know cost is a factor for these manufacturers but jeeze....

Patrick Lombard · Dec 27, 2011

Replaced my years ago: http://sbo.sailboatowners.com/index.php?option=com_mtree&task=viewgallery&link_id=7376&Itemid=257

Mike Culik · Jan 30, 2012

My replacement compression post was made of two very fine grain pressure treated 2X4’s laminated together, which I routed out a 1”x1” channel for the wiring. I wasn’t to concerned about the beam profiles, a little larger cross section(s) is better for the load as far as I’m concerned. The cross beam was opened up with the vibrating tool (cut like butter) and cross beam wood replaced… The length was measured from what remained of the existing post and the "raised" distance, plus 1/4"

The existing wiring coming out of the cabin ceiling beam, was more offset to the stern, so I rotated the post backward so the wiring channel is now facing stern. This past Saturday, I noticed that even with the new pipe and lots of caulk, I still have water leaking down the wiring. For now the mast load issue has been resolved. I had new trim boards milled to the new dimensions, but I’m holding off installation because of the continued leaking ...

The final resolution will be to pull the mast…..
At that time, I will do an instrument upgrade i.e. new Windex and wiring.

In the mean time …. I noticed there is no weep hole at the base of the mast!
Do others on this site have experience with adding weep holes at the base to help eliminate or reduce the water leaking down the wiring/pipe in the mast?

Regards to all,
And thank you for the words of encouragement,

Mike

Compression post surgery

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