Attaching Coaming

oldpaint

Active Member
Greetings from Cape Cod.

I am reattaching the coaming to the deck of a 1969 sunfish I've owned since new. The old caulk was cracked and allowed seawater to get underneath when the boat plowed through waves. When I removed the combing I was surprised to see that the caulk was only applied to the cockpit side, not underneath. I was also surprised that the screws were machine screws going into copper screw anchors. What kept the seawater from finding its way past the screw threads into the hull? Should I put locktite or something else on the screws? I've never dried out the hull and this week I weighed it - 129 lbs.
 
My Sunfish is from 1964. When I removed the coaming to clean up the boat, I also found machine screws. I also noticed that the brass/bronze anchors (aka Rivnuts) did not have access all the way through. Therefore, no water could go through the rivnut and get into the hull. Unfortunately, when I attempted to put the screws back in, most of the rivnuts spun in place and would not pull tight. I ended up drilling out each rivnut and using pop rivets.
 
Thanks for the info. The rivnuts are tight and did not spin when I put the screws back in this morning. Now waiting for the 5200 on the trailing edge to cure.
 
Thanks for the info. The rivnuts are tight and did not spin when I put the screws back in this morning. Now waiting for the 5200 on the trailing edge to cure.
I agree with Beldar, there's no need for 5200; it may bite you later on...
 
I appreciate your concerns. You are right that It is overkill, but the 5200 is not under the splashguard so it could be cut off with a razor and debonder. A lot off work but the need to do so is a hopefully unlikely scenario.
 
Hi... I also am removing, painting,and now getting ready to reattach the coaming. About half of my rivnuts have pulled out and they are not easy to buy. One archived article suggested bolts,washers and locknuts. I would love to use them, but....the foam supports are in the way under the deck through my inspection ports. Pop rivets, the other suggested route, also are problematic as here too I would need access to insert a washer and caulk on the underside of the rivet. Any other approaches? I checked out some lead anchors, and some plastic wall anchors, and those Molly fasteners, but they are questionable. What else could I try? Thanks.
 
Hi... I also am removing, painting,and now getting ready to reattach the coaming. About half of my rivnuts have pulled out and they are not easy to buy. One archived article suggested bolts,washers and locknuts. I would love to use them, but....the foam supports are in the way under the deck through my inspection ports. Pop rivets, the other suggested route, also are problematic as here too I would need access to insert a washer and caulk on the underside of the rivet. Any other approaches? I checked out some lead anchors, and some plastic wall anchors, and those Molly fasteners, but they are questionable. What else could I try? Thanks.
I just stumbled on a possible repair for coaming / splashguards that have come loose. :)

Mine had been torn off in some misadventure :oops: and repaired by the previous owner with drywall anchors. :confused: So how to fix when half of the fasteners are blocked by the foam blocks? (And after discovering that the holes were big enough to stick one's finger through)? :oops: "Kap-Toggle" would have been my first choice, but they're over $5 each! :confused:

These are essentially coiled springs, and should accommodate either screw- or machine-screw fasteners. They are also available in "tang-less" form.

Fullscreen capture 8312019 83326 AM.bmp.jpg
Although these are metric, I can see drilling the present holes out to accommodate a tight fit by one of these "sleeves" from this selection. I don't think these are tapered, but you can turn them up-side down, epoxy them in place, and re-use the existing screws. These "screw sleeves" are made of stainless steel, so there's nothing to corrode.

In my case, I've just this week built the holes back together with shredded fiberglass cloth and epoxy. I would like to have tried these :( but it's too late. I've since deleted the page they were on, but a search would be helped using "screw-sleeves", "Preygo" and "Heli-Coil".

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