Thanks to all of you who have responded with wise counsel.
I took a closer look today after the rigger pulled away the head liner and exposed the problem. The bulkhead is placed aft of an ideal structural location in order to gain room for the head. The chainplate is angled because the starboard shrouds are forward of the bulkhead, meaning the loads from the chainplate to the shrouds are carried about 20% or so from vertical, and that angle is what is torquing my bulkhead and causing it to bulge in the middle as the bottom edge of the chainplate compresses the wood. The head itself is a pre-fabricated affair dropped into the boat before the deck was fitted, and because it is fairly rigid, it holds the bulkhead in place where it meets along the hull. However, the middle of the bulkhead, where the chainplate is attached, is unsupported, and under the load of years of racing it has simply failed.
The rigger is noodling a fix, but his initial idea was to build a stainless steel box (or channel frame) to attach to the salon side of the bulkhead. The box/frame would be much more rigid than the bulkhead and carry the load over a larger area when through bolted. He would then cover the repair with plywood and teak veneer. I am having an engineer with lots of sailing experience take a look to see if he agrees with that concept.
I'll let you know my progress. Best to all.
Bob
Robert E. Izmirian
rizmirian@comcast.net
From: Mark Lemon [mailto:marklemon@centurytel.net] Sent: Thursday, September 17, 2009 8:49 AM To: Robert Izmirian; olson911@sailpix.com Subject: Re: Do I have a unique problem?
I don't think your problem is unique and doubt if a bigger chain plate would make a difference. When the boat is on a starboard tack, the shrouds are tensioned and this actually pulls the bulkhead upward toward the deck, causing compression at the joint, and while on port the tension is released. Over time stress cracks may develop in areas where a load is put on and then released, and it is common in boats that have bulkheads tabbed to the hull and deck, just more noticeable in boats that don't have headliners and trim that hide these points of contact. If the bulkhead has come loose and it isn't due to water damage and there is no rot; the problem can be fixed by grinding out the damaged area and applying a new fillet of structurally thickened epoxy and fiberglass tape. I think West Systems has literature available for such a fix. I'd use an epoxy resin and not polyester. The epoxy is stronger and has some give to it, where as polyester resin is more brittle, and with epoxy, you won't have to deal with the odor from the polyester fumes, which can be overwhelming in a closed area.
I haven't seen any problems like this on our Pacific built 911. Fingers crossed.
Mark Lemon
From: Robert Izmirian <mailto:rizmirian@comcast.net>
To: olson911@sailpix.com
Sent: Wednesday, September 16, 2009 10:48 PM
Subject: Do I have a unique problem?
Hello all, it's been very quiet for a very long time among you O911 owners. Hope this finds everyone well.
I have an early Ericson built boat--1988-which I've raced hard on SF Bay. The Ericsons, like the Pacific built boats, tie off the starboard shrouds to a steel plate affixed to the head side of the bulkhead separating the head from the salon. My bulkhead looks like it's starting to fail. First I had cracks develop in the Melamine finish on the head side of the bulkhead, but they were small and not worrisome. Now I am getting more movement in the bulkhead, as if it is torquing under the load of the rig. My rigger is looking for a solution short of replacing the bulkhead, possibly by fabricating a larger steel plate onto which to tie the chain plate to spread the load over a larger area with more fasteners. The difficulty with this possible solution is that the bulkhead has two separate planes, one of which is the wood trim adjacent to the sink, making fabrication and installation of a new fastening plate much more of a chore.
Has anyone experienced this problem, and if so, do you have a fix? Thanks.
Good sailing to all.
Bob
Jane Doe
28555
Robert E. Izmirian
rizmirian@comcast.net Received on Thu Sep 17 22:24:12 2009