CD Typhoon Compression Post Question

[Bensimon132]

Hello all,
I have a question directed at anyone who has installed a compression post in a CD weekender. I was wondering if there were any specific measurements for how tall the deck should be, so I know how much I need to raise it, if any at all. If not, and you have installed a compression post that worked well, could you provide me with the measurements? Any advice on how to build and install the post is also welcome. Thank you.

[Paul D.]

Ben,

I put a post in my old Typhoon. I used a 3x3 oak post with a basement jack down the bottom set on a sealed oak 2x4 to spread the load on the cabin sole. I didn't have a specific set of measurements to go with so I put it in and screwed it up to have some tension on an oak cabin beam I made to span the width of the cabin and spread the load there as well. The oak post ended up probably around about 24-28" long. I ended up epoxying the beam in and varnishing so it looked the part. Everything else was removable but I never moved it.

I would only check the coachroof once in a while to make sure there was no dip or hump that was noticable. Never seemed to have a problem with the rigging losing tension. My friend has the boat now and to my knowledge he has not adjusted it either. The basement jack was a basic $20 one from a hardware store.

When I purchased the boat it had a rather profound indent in the hull at the waterline from being improperly stored on the trailer. When restoring it, I used the basement jack to set some pressure on the spot from the inside and set some hot shop lights near the hull on the outside to give it some safe heat. The indent came out for the most part then and after a season or two with the trailer fixed became unnoticable. Fibreglass is some pretty wild stuff.

Hope this helps.

[Dick Villamil]

I have photos of the easily-installed, non-invasive compression post I installed in my Typhoon weekender. It is removable, adjustable and there are photos of similar ones in this web site if you query it in the archives. I placed a 1x10 section of pressure treated wood shaped to fit snugly on the cabin sole that had been varnished to look like it belonged (placed on the cabin floor under the mast step) with a stanchion base. I then used two sections of stainless tubing to another stanchion base positioned on a block of wood with recesses to anchor it under the mast step by positioning it over the bolts that attach the mast step. It has a 12" section of allthread (I used zinc plated to keep the cost down) coated with CRC protectant to prevent rust or corrosion with two ss nuts and washers. You can adjust it according to your boat's needs - only do a little bit of compression releif at a time. I have had this installed for 4 years and it has never moved. SInce the stanchion bases are open I needed to make an aluminum plate to keep the post from abrading the wood blocks. I cannot place the porta potty and boards with cushions over the porta potty spaceunless I remove the compression post but I only day sail Victoria. PM your email address and I can send photos of the finished product. I decided to not cut holes in the cabin sole nor in the boards that cover the porta potty area. The entire post cost me about $30 and some elbow grease.

[Oswego John]

Oswego John
Boat: '66 Typhoon "Grace", Hull # 42, Schooner "Ontario", CD 85D Hull #1 Steve Laume wrote:

I would agree that this would be a major and difficult repair if indeed the mast support structure is destroyed. It does seem like a unique and unlikely problem. This is one area I don't recall anyone posting about problems.




Hi Steve and all,

I realize that what is printed next is not exactly what you are referring to. It does apply, somewhat, to sagging decks, turnbuckles and the spinoff effect that occur when the mast support fails. FWIW:


Oswego John
Boat: '66 Typhoon "Grace", Hull # 42, Schooner Ontario, CD 85D Hull #1
Posted: Sat 3/19/11 6:08 pm Post subject: "What To Look For"

The following is a reprint of a post that I made about a year ago. It concerned a boat with a depression on the cuddy roof that was caused by mast compression.

--------------------------------------------------------------------------------

I would like to add something to the excellent advice that the Tadpole Sailor recently gave. My $.02 is kind of basic info and maybe not worthy of mention. Anyhoo....

I had occasion to help a guy with a sunken roof deck. He couldn't figure out what his problem was. He measured carefully and constructed a compression post. He did a real, fine job of it. Just one little problem, he didn't raise the roof to normal before setting the compression post.

It is possible to jack the deck up with the mast in place. Just make sure that there is plenty of slack in the stays and shrouds before attempting to elevate the deck.

Without going into detail at this time, you can jack the deck up from inside if the indent isn't too much. I jack it a little bit at a time, maybe a 1/4" and let it set for a bit to readjust. How long is a bit? I don't know so please don't ask. A bit is just a bit. After a bit, jack it up another 1/4" or so until you have a crown in the deck. Don't be too alarmed if you hear the deck "pop" to its normal position.

To quick check for what Robert (Tadpole Sailor) was mentioning, I use two methods. The simplest is to lay a straight edged piece of wood, or whatever, across the roof of the cuddy cabin, adjacent to the mast position. The center of the convexed arced roof should be approximately 3/4" higher than the edges. If the roof is flat or concaved, the boat definitely needs a compression post.

There is another quick check. Look at the stay and shroud turnbuckles. If they are made up short as much as possible, there is a good reason to look farther. When the roof compresses, the bottom of the mast drops with it. The lowered mast allows slop in the shrouds and stays. To try to overcome this slop, the owner makes up on the turnbuckles (Ed. this compounds the original cause of the problem /Ed) to the max but in cases of deep indentation, the turnbuckles can't adjust enough to take the slack out of the standing rigging. Hence, an untuned boat.

As stated earlier, there are at least two methods I use to raise a compressed roof to its proper position. Jacking from the inside is the easiest and quickest method. When dealing with severe compression, most times the roof can be pulled up from the outside. I helped another guy with a brand X who tried to jack his roof up and in so doing,he opened up his hull to deck joint. When you pull the roof, this won't happen.
_________________
O J
"If I rest, I rust"
Voting Member #490

[Jim Buck]

I raised a cabin top on a Ty Weekender several years ago now and used the measurement of 38" from top of floor to underside of cabin top where the mast step bolts are located. the measurement came from a post in the archive (I think this was one of Bly's posts). I used a hydraulic jack and a hardwood post with a hardwood base on the floor. Atop the post I placed a flat square of hardwood maybe 4"(?) square. I also placed a stack of hardwood under the floor as I was afraid the point load on the floor might cause a failure of the floor or at least flex which would throw off my measuring. In other words, I had support from the keel all the way to the cabin top with the jack in line. My cabin top raising was done during the dog days of summer as I thought I would have more elasticity in the materials I was trying to move. As OJ suggests, take it a little bit at a time. You might consider waiting until it's warmer to reduce the potential stress on the hull-to-deck joint. I think maybe the compression of the cabin top was caused by leaving the mast in place over the winter in a cold environment and maybe the yard cranking it down tighter in the spring. My main point is to support that floor underneath while jacking to avoid flexing or failure, doesn't take much to provide some insurance there. As to compression post, I'd opt to go for something like Dick's set-up as it seems to be the best from a structural point of view. I now sail a Ty Daysailer which doesn't have this issue; you just get wet when it rains. Just my $0.02.

[Steven_Shore]

I would like to resume the discussion on this evergreen topic.

I've combed through 17 pages of search results and agree with the gentleman who wrote that there are as many variations to this solution as there are personal Scotch preferences.

Having been through everything, I've settled on my choice of materials: 2 lengths of 1" stainless steel tubing, with a zinc plated, 3/4" threaded rod, stainless washers and nuts, placed into stanchions. This assembly would be placed beneath a hardwood block, approximately 4" square, with with recesses to anchor it under the mast step by positioning it over the bolts that attach the mast step.

That's the easy part.

The $64 question is do I rest the compression post stanchion base on a piece of hardwood 2x10 (x the width of the cabin sole directly beneath the mast) on the cabin sole, or do I cut through the sole and set the post on a block or a plate that's mounted directly atop the keel?

My gut tells me to set the base on the hardwood set on the cabin sole. If I allow an extra 5" length for the threaded rod, I'll always have the option of drilling the sole and extending the compression down to the keel later. My rationale is that since Cape Dory designed the mast to sit atop the cabin top to begin, how much support do I really need for the compression post? The accounts that I've read where others have mounted the post to the cabin sole seem to have worked well. Distributing the pressure across the 2x10 should be enough.

Would anyone be kind enough to share their experiences, opinions or warnings? I'd love to hear from you!

[Markst95]

I did the drilled the hole in the floor method and ran a 1"stainless pole from the cabintop to the keel. My boat didn't have any compression just wanted to strengthen it. I cut out a piece of 3" PVC pipe to fit from the bottom of the sole to the keel and placed it under the hole for the post. I cleaned out an inch or so of the balsa core around the hole and then proceeded to fill the pvc pipe around the stainless post up with thickened epoxy and chopped strand. I filled it up until it flowed into the gap in the floor where I had removed the balsa, effectively locking the post in place. I used a piece of teak on the top to make it look nice. It is solid as a rock and I used it to help pull myself out of the forward bunk.

[shavdog]

Heres a picture of what I did

[Steven_Shore]

Thanks everybody for your generous advice,

I settled on the 'hole in the sole' approach, resting the base of the post on a small square of stainless steel, epoxied directly atop the keel.

From McMaster Carr I ordered a 36" length of 1" stainless steel tubing, with 0.12" wall thickness. I also ordered an 18" stainless steel, 3/4" threaded rod that fit snugly inside the tubing, as well as a 5 pack of stainless steel nuts. With tax and shipping, that set me back $131.67.

I also purchased 2 1" stainless steel, 90 degree rail bases and they cost a combined $66.00. You could probably find them for less but I needed to eyeball them so I picked them up at my local West Marine store.

Finally, I scrounged a hardwood block and like just about everyone, drilled 3 holes in the top so it would fit flush against the three mast step bolts that come through the headliner. I attached one of the rail bases to the underside of the wood block.

I cut a hole in the sole and then screwed the other rail base above the hole.

I cut the steel tube in two and passed one through the rail base and the hole, coming to rest atop the stainless steel plate epoxied to the keel.

Finally, I passed the rod through the lower tube and set the upper tube into the upper rail base and then screwed the nuts to form the compression post. I used two sets of two nuts, upper and lower, to lock everything in place.

Now let's see if the shrouds don't slack off on me halfway through the season like they have the last couple of years...

[Markst95]

Very Nice- Combines the best of all the ideas!