Chain Plat Bulkhead 1976 SJ21

[dtexpert]

I am a newbie to sailing and boat owner. I recently bought a SJ21 and am working to get it in sailing condition. The chain plates are mounted to a translucent nylon material and screwed to the sink panel on the starboard and the storage compartment on the port side (which has pulled out). I am not sure if this is a good support for the chain stays. My question is there supposed wood bulkhead there and if yes how is it supposed attached to the boat.

[cklamp]

Any chance you can take some pics? It would help to see what you're talking about.

Thanks
Christian

[kuriti]

I don't have a sink, so i am not exactly sure of what you speak, but yes, there is traditionally a wooden bulkhead. Here is a pic of what mine looked like (not my boat in the pick though):

http://www.tommysolomon.com/photos/1981 ... small/#nav

His are painted white and glassed to the boat, but have the same dimensions as the original. I stole Krysia Ry's idea below. He did his in steel, I used aluminum.

http://www.sj21fleet1forums.org/viewtop ... 1152#p1152

here are mine and some cost info:

viewtopic.php?f=20&t=152

[dtexpert]

Thanks for the photos. They are a great help.

[Kensho!]

Same question, but mine is a '71 MKI. It looks the chain plates are an inverted "T" that have been glassed into the wall of the coach-house between the port-lights. There is a small stiffener at the intersection of the deck and the side of the hull. Last weekend we were out sailing in a nice little breeze (10 knts) with a few gusts (15 knts). The last gust to hit us (probably closer to 20 knts) was accompanied by a rather loud "pop" that shook the whole boat. Once back in the marina we noticed a crack where the stiffener (noted above) joins the deck.
My thought was to fill the crack with 3M 5200 and then re-glass the stiffener to the deck and hull. Any thoughts?

[kuriti]

a rather loud "pop" that shook the whole boat.

Not words one likes to hear. a pick would be good. I would imagine that all fiberglassing should be done first and then stuff mounted with 5200 (i prefer 4200).

[Kensho!]

Finally figured out how to attach some photos - (Sailor - not a computer guy)

Close-up of damaged stiffener

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looking inside, starboard, forward, and down

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Note, A previous owner had cut a hole in the shelf. As luck would have it, he kept the piece that was removed, so I epoxied back in.

Starboard side

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The "T" that is faintly visible in the side between the portlights is the chainplate.

The Port side looks very similar. Only the crack is not nearly as visiable

[kuriti]

Looks like a previous owner fiberglassed a vestigial bulkhead into the deck and hull. You're in a MK I, so i can't say with certainty, but i have never seen that set up before. I would recommend cutting out the previous work and either replacing with a traditional wooden bulkhead or the aluminum T that I posted earlier. I don't think that that set up is sufficient for the forces at play. You could either buy new bulkheads from Steven, or just track the outline of the side of the boat onto marine plywood and cut the other side flush with your box. I don't think there is some highly engineered design to the bulkhead, but it needs to transfer the load down into the bottom portion of the hull, or the cracking you are seeing will continue.

[cklamp]

MKI's don't have the inside wall things you MKII\III guys have... All forces are directed down the side of the hull by that glassed in inverted T. His setup looks fairly stock as compared to my Mizu. I'd say pull out that thing next to your "stiffener", grind things out, and reglass it all in.

Up to you how you want to handle the chainstay. You could pop the top off and make sure it's nice and dry inside, and then reseal it, or grind the whole thing out to make 100% sure it's really dry inside, then glass the whole thing back in.

Later
C

[Kensho!]

[img][img]

Pictures are in the wrong order, but you get the idea

I started but grinding down the stiffener and all of the surrounding area. I got down to a layer of glass and then cleaned it all up. It looked like the stiffener was just epoxied on originally. it is a 40 year old hull though.
I glassed on three layers of mat tieing in the stiffener to the hull, deck, and coach roof.
I very closely inspected the chain plate and the cap on top of the coach roof. It still looks good and solid with no signs of water intrusion.
Heres hopping for good winds next wekend