Folks, I know mast compression is a common thread in these forums, but most of the posts seem to deal with the roof rather than the floor. I have problems with both. The floor in my '79 27' is depressed about a half inch. Judging by the inspection hole I drilled, the problem appears to be the stringer rather than the glass/plywood floor sandwich, which is in excellent shape. First question: Should there be wood in these stringers, as some posts suggest? The one under my compression post is hollow. I didn't find any indication that there was wood there once. I tapped all of the stringers exposed under the bilge cover, and they all sound hollow. That said, it seems crazy to set the compression post on a hollow glass stringer. Second: Can I set an aluminum or steel compression post directly on the bilge bottom? I assume that there is steel under the glass, or Hunter couldn't have bolted the keel to it. Does anyone have a cutaway view of the hull? Thanks and regards Todd Mason
mast compression on cabin sole
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Same Problem On Mine
I have the same problem. I would love to get an answer, too. I've been trying to come up with a jacking scheme to lift the post/roof/mast. Then shim with something like pieces of a poly cutting board.
I have the same problem. I would love to get an answer, too. I've been trying to come up with a jacking scheme to lift the post/roof/mast. Then shim with something like pieces of a poly cutting board.
Early 27's
Seem to have different construction than later ones. I recently got a picture of a 81 being cut up for salvage and noted the rib and strengthing of the hull was quite a bit more sophisticated than my 76. Mine, frankly was a sloppy glass job with hollow stringers, two of which are craked, along with a crack in the hull. I've come to the conlusion the damage was most likly from improper standing - a center stand aft of the keel on these boats is important. I am about to cut out the sole to make repairs, and yes it looks like the compression post just misses a stringer -
Seem to have different construction than later ones. I recently got a picture of a 81 being cut up for salvage and noted the rib and strengthing of the hull was quite a bit more sophisticated than my 76. Mine, frankly was a sloppy glass job with hollow stringers, two of which are craked, along with a crack in the hull. I've come to the conlusion the damage was most likly from improper standing - a center stand aft of the keel on these boats is important. I am about to cut out the sole to make repairs, and yes it looks like the compression post just misses a stringer -
Reply to Bill
This same 27 has an aluminm weldment sandwiched between the teak at the top of the bulkhead. I spreads the load across the whole bulkhead instead of just the post. I can take a picture if you wish.
This same 27 has an aluminm weldment sandwiched between the teak at the top of the bulkhead. I spreads the load across the whole bulkhead instead of just the post. I can take a picture if you wish.
I don't see any metal
Bill, You're describing a L-shape brace tying the bulkhead and the cabin roof, right? There's nothing between the ceiling and the 3/4" plywood bulkhead in my boat. I have the compression post out along with all the trim. Anyhoo, the bulkhead is also a half inch low at the compression post side. Todd
Bill, You're describing a L-shape brace tying the bulkhead and the cabin roof, right? There's nothing between the ceiling and the 3/4" plywood bulkhead in my boat. I have the compression post out along with all the trim. Anyhoo, the bulkhead is also a half inch low at the compression post side. Todd
jacking suggestions
I have mastered the jacking. I doubled up 2x8s, and set them on the raised platform for the head to right (facing forward) and through the access hole on the vanity to the left. I set a basement jack on them and bolted it to the mast step. (A basement jack is a four-inch pipe with a screw jack set in its top; $25 at Home Depot.) You'll have to trim it to fit. You'll also have to loosen the stays as you raise the ceiling. On my boat, jacking took out about half of the deck's concavity uptop under the mast. With the weight off the floor, a small bottle jack or scissors jack in the bilge should get it back where it belongs. But that's not much of an answer if the stringer continues to collapse.
I have mastered the jacking. I doubled up 2x8s, and set them on the raised platform for the head to right (facing forward) and through the access hole on the vanity to the left. I set a basement jack on them and bolted it to the mast step. (A basement jack is a four-inch pipe with a screw jack set in its top; $25 at Home Depot.) You'll have to trim it to fit. You'll also have to loosen the stays as you raise the ceiling. On my boat, jacking took out about half of the deck's concavity uptop under the mast. With the weight off the floor, a small bottle jack or scissors jack in the bilge should get it back where it belongs. But that's not much of an answer if the stringer continues to collapse.
There is wood in our '77 h27 grid
Bill, take down the mast, and the compression is relieved. You might get away with just loosening the stays, which pull down on the mast with around 2 tons if they are tensioned right. Todd, the "grid" or stringers glassed into the bottom is key to the structure, providing stiffness to the hull and keel mount as well as holding up the compression post. There definitely should have been wood in there at one time. In any case, you need to rebuild the wood and the glass under the post. That will require cutting away the floor/liner over the stringer, but you can learn to do the glass work - I have a friend who replaced several stringers and a couple of engine mounts on a Juneau 32, and he said it was just time, not much materials. As for the other stringers that make up the grid, I don't know how critical they are in a structure that we now know was overdesigned due to a lack of sure knowledge about the strength and durability of fiberglass. David Lady Lillie
Bill, take down the mast, and the compression is relieved. You might get away with just loosening the stays, which pull down on the mast with around 2 tons if they are tensioned right. Todd, the "grid" or stringers glassed into the bottom is key to the structure, providing stiffness to the hull and keel mount as well as holding up the compression post. There definitely should have been wood in there at one time. In any case, you need to rebuild the wood and the glass under the post. That will require cutting away the floor/liner over the stringer, but you can learn to do the glass work - I have a friend who replaced several stringers and a couple of engine mounts on a Juneau 32, and he said it was just time, not much materials. As for the other stringers that make up the grid, I don't know how critical they are in a structure that we now know was overdesigned due to a lack of sure knowledge about the strength and durability of fiberglass. David Lady Lillie
Jacking
My boat is an '83. I hadn't thought about a basement jack. That will work. I had already planned to loosen the stays. Right now everything is pretty stable, for weekend day sails on the bay. I'll probably a wait to take this on in the fall. Last time down I replaced the front hatch. It's time to play, if the weather cooperates.
My boat is an '83. I hadn't thought about a basement jack. That will work. I had already planned to loosen the stays. Right now everything is pretty stable, for weekend day sails on the bay. I'll probably a wait to take this on in the fall. Last time down I replaced the front hatch. It's time to play, if the weather cooperates.
Shim
My problem is the calapse at the compression post base. I plan to build up under the stringer and get the bulkhead straight at the same time. My roof looks pretty good. I think entire deck molding has taken up the settlement of the compression post.
My problem is the calapse at the compression post base. I plan to build up under the stringer and get the bulkhead straight at the same time. My roof looks pretty good. I think entire deck molding has taken up the settlement of the compression post.
been there
I had this problem just the other year ago.. At first, the compression was first noticed in the cabin roof but not in the floor and by the time the boat was hauled and mast was stepped, the floor was showing signs of indentation. After the boat was hauled and mast stepped, I used a simple scissor jack under the floor and raised the whole kitten kabootle till the cabin roof was where it should be (eye balling it anyway). Then I cut away at the roof around the mast step as far as I could (or wanted to), removed the foam core, replaced that with a stainless plate, added glass, re-glassed what I could and added some mat to the stringer under the floor; under the compression post. I however did not find any hollow stringers and I didn't have any depressed stringers below the mast compresion post... And yes, the compression post on my 79' 27' is not exactly on the stringer and neither is the mast on the compression post. Everything is just slightly off, by inches. Anyway, it took time, not so much money and now the pocket door to the head has to be latched closed or open or it will just slide all over the place and bang like hell. So, I'll call it a successful repair.
I think the hardest part was the gelcoating and getting the colors to match...
I had this problem just the other year ago.. At first, the compression was first noticed in the cabin roof but not in the floor and by the time the boat was hauled and mast was stepped, the floor was showing signs of indentation. After the boat was hauled and mast stepped, I used a simple scissor jack under the floor and raised the whole kitten kabootle till the cabin roof was where it should be (eye balling it anyway). Then I cut away at the roof around the mast step as far as I could (or wanted to), removed the foam core, replaced that with a stainless plate, added glass, re-glassed what I could and added some mat to the stringer under the floor; under the compression post. I however did not find any hollow stringers and I didn't have any depressed stringers below the mast compresion post... And yes, the compression post on my 79' 27' is not exactly on the stringer and neither is the mast on the compression post. Everything is just slightly off, by inches. Anyway, it took time, not so much money and now the pocket door to the head has to be latched closed or open or it will just slide all over the place and bang like hell. So, I'll call it a successful repair.
I think the hardest part was the gelcoating and getting the colors to match...
A hollow stringer
I think. It sure sounds hollow, and is a lot different than the 81 H27 I've seen. (1976) Jim it sounds like you removed your bulkhead. Ive been avoiding that as most of my problems are aft of the keel, but this is what the stringers all look like, including what I can see below the compression post.
I think. It sure sounds hollow, and is a lot different than the 81 H27 I've seen. (1976) Jim it sounds like you removed your bulkhead. Ive been avoiding that as most of my problems are aft of the keel, but this is what the stringers all look like, including what I can see below the compression post.
I didn't remove
I didn't take any pictures, although I might have one of the step in the cabin before I started the work. The construction is definately different on my 27 than the pictures you posted. But no, I didn't remove the bulkhead at all. The whole thing had dropped just enough that I could actually see the construction pencil marks from the carpenter on the cabin roof and was able to bring everything back to where it was originally. The scissor jack I used, was borrowed from the local fire department and I was able to just barely get the head in there and lift the post up from inside the bildge. Of course, this didn't take much pressure at all because there was no weight load. The hardest mental part I think, was taking the 7.2v makita skill saw to the top layer only of the foam sandwich deck outside... I'm glad it's done though, even the deck in adjacent areas feels a little more solid and when the kids are diving off the deck, I can hear their footsteps without hearing the foam crunch. So all in all, a gallon of epoxy, some mat and a little bit of ingenuity and all is good..
I didn't take any pictures, although I might have one of the step in the cabin before I started the work. The construction is definately different on my 27 than the pictures you posted. But no, I didn't remove the bulkhead at all. The whole thing had dropped just enough that I could actually see the construction pencil marks from the carpenter on the cabin roof and was able to bring everything back to where it was originally. The scissor jack I used, was borrowed from the local fire department and I was able to just barely get the head in there and lift the post up from inside the bildge. Of course, this didn't take much pressure at all because there was no weight load. The hardest mental part I think, was taking the 7.2v makita skill saw to the top layer only of the foam sandwich deck outside... I'm glad it's done though, even the deck in adjacent areas feels a little more solid and when the kids are diving off the deck, I can hear their footsteps without hearing the foam crunch. So all in all, a gallon of epoxy, some mat and a little bit of ingenuity and all is good..
thanks
Thanks for all of your help. I plan on filling my stringers with resin on the general principle that too strong is better than the opposite condition. I also plan to install a metal compression post right under the mast for the same reason. Regards Todd Mason
Thanks for all of your help. I plan on filling my stringers with resin on the general principle that too strong is better than the opposite condition. I also plan to install a metal compression post right under the mast for the same reason. Regards Todd Mason
One more picture
I have been thinging about this since my earlier post - Maybe the intent was to support the offset of the mast to the comperssion post, it is'nt the width of the bulkhead as I originaly thought. Injecting epoxy into the stringers - thats one I never thought of, I would think it woulf have to be thickened epoxy, but maybe there is a way to do it with a caulk gun These are important topics for all of us who own old boats - -
I have been thinging about this since my earlier post - Maybe the intent was to support the offset of the mast to the comperssion post, it is'nt the width of the bulkhead as I originaly thought. Injecting epoxy into the stringers - thats one I never thought of, I would think it woulf have to be thickened epoxy, but maybe there is a way to do it with a caulk gun These are important topics for all of us who own old boats - -
hey Randy
I didn't add any supports to the inside, and yes I know, I'm bad at explaining things... The glass I added inside the boat was to offset the load to the stringer as the compression post seems to be 3" aft of the mast and the mast appears to be centered over the stringer. The plate I added outside in the sandwich went from porthole to porthole and not down to the porthole, thus, evenly distributing the weight over a great deal of deck and transferring it to the hull. This eliminates the need to add the gauky stuff inside, or at least, it has for me. After all of this discussion, why would one center the load of the mast offset to the compression post and on top of that, not put the compression post on the stringer and rely on a foam core sandwich of a deck rather than being center through directly with maybe even a wood block in the cabin roof?
I didn't add any supports to the inside, and yes I know, I'm bad at explaining things... The glass I added inside the boat was to offset the load to the stringer as the compression post seems to be 3" aft of the mast and the mast appears to be centered over the stringer. The plate I added outside in the sandwich went from porthole to porthole and not down to the porthole, thus, evenly distributing the weight over a great deal of deck and transferring it to the hull. This eliminates the need to add the gauky stuff inside, or at least, it has for me. After all of this discussion, why would one center the load of the mast offset to the compression post and on top of that, not put the compression post on the stringer and rely on a foam core sandwich of a deck rather than being center through directly with maybe even a wood block in the cabin roof?
Jim -
Thanks, you explained it better than I read it. Good question as to why these things seem to be off - I guess they were production boats built by different crews. I also have a Hunter 25 and everything lines up, but there is a big wide notch cut in the bottom of the stringer so the bildge would drain - All factory done, needless to say I have a few wedges pounded under it.
Thanks, you explained it better than I read it. Good question as to why these things seem to be off - I guess they were production boats built by different crews. I also have a Hunter 25 and everything lines up, but there is a big wide notch cut in the bottom of the stringer so the bildge would drain - All factory done, needless to say I have a few wedges pounded under it.
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