What's under there?

[ewoden1]

I have an 8.0 C with a sagging sole in the cabin under the compression post. Before I tear into her to restep this area one question: Is there a cross member under the plywood or is the compression post stepped just on the sole w/o an underlying support?

I ran a wire through the bilge via the table socket hole fore of the compression post and it seemed that there's nothing under that post.

 

[BobM]

Good question

I have an 8.0 C with a sagging sole in the cabin under the compression post. Before I tear into her to restep this area one question: Is there a cross member under the plywood or is the compression post stepped just on the sole w/o an underlying support?

I ran a wire through the bilge via the table socket hole fore of the compression post and it seemed that there's nothing under that post.

It seems that at most there was a block of wood...which may not be there anymore. I have to do this repair myself. You may wish to consider cutting a nice neat access hatch in the sole and trimming it out. It can be used for storage, etc...and prevent the need to totally replace the sole.

Woody tore into his 9.2A and posted some nice photos, if I recall correctly.

Another member loosened his shrouds and jacked the mast back up into place with a 4x4 before putting a new block in. I may go this route as I clearly have this problem and a major refit (such as dropping the mast) would spoil sailing for me next season.

 

[Bron]

Attached are pictures of the hull under the cabin sole of a S2 8.5. It looks to me like the main bulhead is tabbed to the hull, without a true compression post. The integrity of the mast support is the soundness of the main bulkhead and its tabbing to the hull. In the cabin, that bulkhead is built up a bit to look kind of like a compression post, but i believe most of the structural strength is in the bulkhead itself. There is a sort of beam in the head that is fastened to the main bulkead that spans the head door. It may offer some support to spread the mast load to the port bulkhead . But it looks inadequate as a strong structural member. Just my opinion.

Let me know if anyone want more pics. I have some, but these are the best. They were taken by putting my arm into the access hole under the companionway steps and aiming the camera toward the bow.

It seems that at most there was a block of wood...which may not be there anymore. I have to do this repair myself. You may wish to consider cutting a nice neat access hatch in the sole and trimming it out. It can be used for storage, etc...and prevent the need to totally replace the sole.

Woody tore into his 9.2A and posted some nice photos, if I recall correctly.

Another member loosened his shrouds and jacked the mast back up into place with a 4x4 before putting a new block in. I may go this route as I clearly have this problem and a major refit (such as dropping the mast) would spoil sailing for me next season.

 

[ewoden1]

Thanks guys

The pics really help. I figure at best I have some light cross member tabbed in. After Christlmas I start cutting. Start right around the foot of the post and work my way out towards the margins of the shallow bilge. I think I'll form a footer using a block epoxied and tabbed to the bottom of the shallow bilge area but shy of the side walls to allow drainage from forward to aft areas of the bilge. I figre the step will be best placed so that the majority of the force is downward on the encapsulated keel ballast as opposed to the sides of the keel/hull joint. If I used a tapered block I am afraid I'd wedge the sides of the hull/keel area laterally apart, which mught result in a hull deformity.

Yes I'll put in a deck plate to access the shallow bilge aft of the compression post.

I'll post pics for all to see once I get her opened up.

 

[Bron]

Re: Thanks guys

Whoa! Think this through. First can you get a picture of what's under the sole? Is there an access hole/panel under the companionway, at the deepest part of the bilge? If not, you might want to put one in there first (about 6" x 6"), so you don't go cutting into your sole blindly. Save the piece you cut out to use it to place in the opening after putting a "lip" all the way around the hole on the underside of the floor, to keep it from falling through. The access hole would allow acces to the bilge, which would not be a bad thing, if you don't have access now. I can send a rough sketch if you'd like.

Then, if you must cut the sole, plan a similar 6" x 8" or so (big enough to put your hand through, about 2" aft of the main bulkhead. I'd use the thinnest jig saw blade I can find, so it has a small kerf all the way around. I'd make the lip and reuse the cut out because it would match the floor perfectly. I would not go any wider, unless I was planning to replace the entire sole.

I wouldn't put any wood under the floor. I would either build it up with fiberglass mat and roving, and spread the load across the hull as wide as I can go. Fore/aft location would be determined by mast position; you want the step for a "compression post" to be directly under the mast. I'd also glass in a small tube or something in the center, at the lowest point so water can drain from behind the step. You don't want water sitting behind it. (A 1" plastic pipe, shaped to lie flat against the hull, should work fine.) Then build up the step to an appropriate height, with at least a 4" x 4" flat spot for the top of the step.

Configuration of the "compression post" can be another whole topic of discusstion.

Good luck.

Bron

 

[ewoden1]

Bron, Thanks for the post. I will be putting in an access port to the bilge just forward of the companionway bulkhead. No real way to see what's forward w/o dropping the digital camer in there and clicking away, so that happens first.

When you say main bulkhead, this is an 8.0 CC and there are only two bulkheads, one forward of the engine (the companionway), and one aft of the engine which is the forward side of the aft cabin. There is no bulkhead forward of the companionway save for the chain locker. The compression post is just that, a metal post bolted up top to the throughbolts under the mast step and lagged to the sole of the cabin. If there is a cross member in there under that post I cannot feel it with a stiff wire run through there. Is seems S2 used the sole plywood as the only support.

I thought to contour a block wth width of the bilge and beyons to mate with the bottom of the hull on either site of the bilge for a ways, and epoxy/rove hit in. But I might use a piece of aluminum quarter inch wall square channel and glass that in instead as a bridge across the bilge just unter the existing sole level.. In either case the idea is to not have a dam in there as you pointed out. On top of either I'd glass in a new plywood sole that would spread the load further out over the hull.

One old guy in the marina suggested going with a set of forms just an inch or two fore and aft of the post step and use poured concrete with a tube run along the bottom of the bilge for drainage. I don't race so that wouldn't screw with any rating concerns.

I thought of the jig saw but I will use my shallow cut multitool so I don't have a blade running up and down so near the hull.

Any sketches you'd care to share would be most appreciated by the way ;-)!