Attachment:
DSCF0562.JPG [ 460.11 KB | Viewed 0 times ] This is posted as a
caution to all owners with a C/B and I'm also looking for
advice to fix the problem. The attached picture is my C/B. I removed it this fall to inspect the padeye that lifts the board. When I first looked at it, it didn't seem very bad, but I did notice some minor delamination, cracking and
rust stains. I started chasing the cracks with a grinder, and soon I found some real surprises. First, originally there was a backing plate embedded in the centerboard for the padeye bolt.
That was virtually gone. It was about 3 3/4" x 3/4" x 1/4", but was made out of
aluminum. The biggest piece I found was only about 1/2" long and was attached to the aft bolt on the padeye. The rest had completely corroded away, and only the pocket in which it originally sat was left. So water got in, caused the aluminum to turn to aluminum oxide, which displaces more volume causing the fiberglass to crack further, letting more water in causing more corrosion and damage from freezing. Second, what also really surprised me was that the whole affected area was solid fibergalss resin, with no glass reinforcement. As best I can tell, the outer skin of the C/B (at this location anyway) was gelcoat followed by a layer of fiberglass roving. The rest is solid resin.
The pictures I attached are not great but what they show is the ground out area. There is a large gap which once contained the backing plate (dark area), and the rusted piece is steel plate (~1" thick) that's embedded in the top portion of the C/B. The brown stuff is solid resin. This solid resin is strong but brittle, so its no surprise that it cracked. The bottom line is that the only thing holding my padeye was cracked solid resin, and the bolt treads in that cracked resin. Knowing what I know now, I would inspect this padeye connection frequently. If there is any cracking or delamination, or more importantly rust (which comes frm the embedded steel plate), I would assume the worst and grind out/ repair accordingly.
As repair, I plan on grinding out all the cracked resin, and rebuilding the area with epoxy resin with roving and mat. I'll embed a new backing plate fabricated from Stainless Steel.
If anyone has experience, or repair suggestions please let me know. I'm kinda winging it here!!
On a similar note, I replaced my C/B hinge bracket last year. There are 6 bolts that attach the bracket to the keel, which I understand thread into embedded plates. When I tried to reinstall a few of the bolts last year I found some of the threads in the embedded plates were stripped. I retaped to a larger size in some cases; in other cases, where this didn't work I replaced the bolts with SS lag screws. At the time I thought it strange that the bolts threaded out OK, but the threads were shot when I reinstalled. I'm thinking now that those embedded plates may also have be made from
aluminum. If that's the case, there not much holding that bracket and my C/B to the keel, so not to take any chances I'm replacing all bolts with lag screws this Spring.
Good luck. I hope this was helpful, and any repair suggestions/comments would be greatly appreciated.
Jim Voelxen
Odessey #191