Coaming Replacement

LQT420

LQT420

Member
Hi,

Has anyone ever done a coaming replacement? I'm in the process of refinishing a '78 hull and would like to replace a beat up old coaming. My concern is this: Based on diagrams of where the foam blocks are, it seems that I won't have underneath access to the last few screws on either ends of the coaming through the inspection port. I would like to use stainless steel screws, washers and locknuts to secure the coaming in place, but how do I reach the edges with the foam blocks in the way. Anyone have any experience with this? Please advise.

Thanks.
 
I am in the middle of replacing my coaming. I ran into the same problem with the foam blocks. I installed an inspection port between the daggerboard slot and where the coaming goes. I am going to put two plywood backing strips underneath the fasteners not obstructed by foam, and send self tapping screws into these. I grinded the glass down around all of the fastener holes, and filled them with a structural epoxy putty. I will redrill the holes, smaller, so the self tapping screws have something to bite into. Hopefully, this will be enough to hold it down, where the foam keeps me from putting a backing block in. I also like to smear all of the threads of my fasteners with some 5200. hope that helps,
-Nick
 
Originally AlCort used brass inserts that were inserted before the deck was bonded to the hull and later they switched to pop rivets. Both methods were used because of interference with foam blocks and the fastener locations. I agree with Steve use the current pop rivet fasteners. But I would get them from Vangaurd or get the specs so you get the correct length and sealed rivets rather than the local hardware versions.
 
On my 78 hull, the coaming is fastened by machine screws. Will I have trouble removing my current screws from the brass inserts on the extreme ends? Also, will the Vanguard pop rivets fit into the current holes for the screws or will I have to glass it over and redrill new holes for the pop rivets? Again, I appreciate your advice.
- Leon
 
I’ve seen screws directly into the deck and some sort of plastic gasket. The old gaskets always crumbled when removed and caulk seems to last better anyway. I have also run into metal inserts in the deck. The ones I found had broken out pieces of deck that needed repair before the coaming could be reset. Rivets seem to work solidly, but I have used screws and anti-vibration nuts with good results too. When the Styrofoam got in the way for the last holes I just dug out a small piece. It didn’t need to be much maybe an inch or two. I use 3/16” x 3/4" aluminum rivets and back-up washers and some caulk to seal it all water tight. There’s a picture of the repair at Windline Sails or Yahoo Sunfish Group. Dow 4200 is my usual caulk, I think if you go with 5200 you probably don’t need screws or rivets at all. Let me tell you though if the coaming gets broken and you want to repair or replace it 5200 is lots harder to get off.
 
If the holes are too big for the pop rivets you can fill them with sealant then move the coaming back 3/8 to 1/2 inch and drill new holes. If you do it right you can't see the old holes. Aluminum rivets that don't need too much tension to set are better than stainless. They need so much tension that you can crack the coaming around the holes.
 
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