Author Topic: Chain Plates - Hull/Deck Joint  (Read 1399 times)

deLight

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Chain Plates - Hull/Deck Joint
« on: April 06, 2016, 08:34:01 AM »
Like all CSY owners, leaky chain plates were my nemesis. I considered Ron Sheridan's solution of outboard chain plates and did not like it for two reasons. (1) The windward performance of the 33 is abysmal to start with and adding more width to the rigging would only make it worse. (2) In order to install the chain plates in there original location something had to be done about the rub strake. Ron eliminated his on Memory Rose, but I find the rub strake invaluable in my "dock by braille" method.

I looked at a few production boats who have their chain plates well inside the hull and used those observations as my inspiration. The objective was to create a sandwich with the external hardware connected to the shrouds and a internal hardware connected to through the hull with a water tight connection through the deck.

I had a machinist make identical pieces from 6mm SS angle. One piece would have a hole for the rigging above the other piece would be welded to the shortened existing chain plate below. And a backing plate for the hull/deck joint sandwich. 4 bolts went through both pieces and the backing plate to secure the upper piece and backing plate in a water tight joint and allow for tension adjustment with the existing chain plate.

In keeping with my standard construction technique, I drilled out the 4 corner holes to 5/8" and by inserting and aligning the bolts from below cast threads using epoxy and chopped fiberglass completely through the cap rail, deck and hull. Be sure to wax the threads so it is not permanently installed backwards.

After carefully, measuring and welding the shortened existing chain plates to the below angle piece, I assembled the entire mechanism using silicone caulk on threads and joints to assure no salt water could enter and cause crevice corrosion. Nylon locking nuts should be used.

While I only have 5 years and a couple of thousand miles on this solution, I am confident of its effectiveness.

Max





deLight

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Re: Chain Plates - Hull/Deck Joint
« Reply #1 on: May 29, 2016, 11:37:36 AM »
Photo of complete lower assembly and chain plate.

Max