C&C 27 Association Forum

ibanezplayer

Member

Compression Post Help

I'm in the middle of replacing my compression post on my '29 MKIII. I've temporarily braced it with a jackscrew while I replace the wooden post. The problem is the compression post has rotted away to the point that I can't get a great measurement.

Could someone check the height from the sole to the wooden cross beam ( shown here: https://i.imgur.com/nSt2H5h.jpg) and comment on whether you have a wooden sole or just the regular fiberglass?

Thanks!

carriden

Member

Re: Compression Post Help

John, someone else's measurements are not likely to do you much good. Although these boats come out of the same molds and are in theory exactly the same, the actual truth is that each boat is a unique individual. Bulkhead placement varies slightly from boat to boat, the exact size and placement of the support beam varies, etc. So, the measurements of my 27 Mk III will be at least several fractions of an inch off of the proper measurements for your boat.

A number of years ago, I had to replace the compression post in Carriden, because the original laminated plywood post had rotted at the bottom. Like you, I used a jack to push up the support beam across the top of the cabin.  When I had the support beam completely straight, I measured the distance from the cabin sole to the underside of the support beam and the deckhead beneath the tabernacle.  I managed to source a piece of solid teak from Exotic Woods in Burlington, which I then cut and shaped to my exact measurements, mimicking the general shape and profile of the original post. I then slipped it into place, tapping it into final position because I had cut it to be a snug fit. This post has served me for over a dozen years now without any problems.

The reason that the original post had rotted was that water which came in through the forehatch, or was spilled in the head, would sit on the cabin sole, having no suitable drainage because it was blocked by the teak sole in the main cabin. To eliminate this problem, I created a small limber hole in the bottom of the main bulkhead, more or less on the centre-line of the boat. I coated the insides of this limber hole with epoxy so that water could not penetrate the bulkhead itself.  Water now drains through the limber hole into the locker under the forward port settee, where it then has a clear and straight path into the bilge. Problem solved. I also cut away the portion of the teak sole under the compression post, so that the new post is resting directly on the fiberglass sole.
Marcus from Carriden

Mk III, Hull #847
Oakville, Ontario

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Marcus Opitz,
Formerly from Carriden, Mk III, Hull #847,
now skippering "Everdina," a 1975 Ontario 32

ibanezplayer

Member

Re: Compression Post Help

Understood Marcus,

Just trying to get as close to standard as I can. There's at least 3/8" of goop slopped on top of the post so I'm not too critical of the overall length, Just want to make sure I'm in the right ballpark.

Secondly, The balsa in my cabin sole is shot so I can't take that as too accurate of a baseline either. I'm considering making a solid section or fitting a hole and going straight through the cored floor to the Knee in the bilge with the new one. 

Thanks for your help and thoughts,
John

chad

Member

Re: Compression Post Help

I have a 1975 mark III and my compression post seams to be bulging at the bottom.
I was thinking I would cut off the offending bit, 6” or so, and add in a shoe of white oak or similar water resistant wood. I would fix it to the existing post with epoxy and an aluminum collar.
Dows anyone see a problem with this kind of repair?
What is the post made of?
Can I do this with the mast up?
The rail for the sliding door on the head needs to be removed?
Will I run into something unexpected cutting it off in situ?
Chuck