Coaming question--gap between coaming and hull

[cnovark]

Hi there. I'm working on my new (to me) 76ish (not sure off the top of my head) Sunfish, starting with the coaming. Until this afternoon, the coaming was attached with these rusted screws and a whole lot of caulk. It leaked. I could stick my hand into the hull through the inspection port right behind the coaming and feel the water dripping off the screws.

Today I took the coaming off. I used a knife to remove the caulk (is that the right term?) and then used a rotary tool to make gashes in the screws so that I could get a screwdriver in (actually my dad had to do it; I couldn't get the screwdriver to budge). Anyway, it took about 4 or 5 hours but I got the coaming off.

I ordered the official Laser rivets for the coaming and plan on doing that sometime soon but I have a problem/question:

My coaming was not and is not flush with the hull when I put it on. There's a gap towards the center (see pictures). Is this normal? I'm concerned that this will make the rivets not be watertight. Like, should I try to force it flush and rivet it in? Will the rivets be strong enough to hold like that? Should I just put a bunch of caulk (or whatever) in there and then rivet it anyway? Will that be watertight?

I'm a novice at all this repair stuff, so I would really appreciate any suggestions . Thanks so much!

 

[Alan S. Glos]

There is always a little gap between the coaming and the deck - yours seems a little more than normal but not off the charts.
Yes, lay down a generous bead of white silicon caulk, rivet away with a little down force with the rivet gun then wipe off the excess caulk to get a good water tight joint between the coaming and the hull. When you are all done, put a little dab of the caulk on reach rivet head to prevent leaking through the hollow rivet shaft.

Alan Glos
Cazenovia, NY

 

[sailcraftri]

You may find that when using the rivet the coaming and deck will pull together. Your coaming must have been refastened at some point and they used steel screws instead of stainless steel. You have the rivets already but another option since you have the inspection port is to bolt the coaming back on. I would use large fender washers inside to act as back up plate for the bolts.

 

[danpal]

Bolting the coaming down seems like a good idea. The only problem I see is that the foam flotation is in the way. Do most people carve through the foam to get to the end of the coaming?

 

[signal charlie]

Danpal if that is the last resort then cutting away a little foam in that area would be okay.

 

[minas man]

In a posting that I did on replacing loose foam blocks in a 1980 sunfish the boat also had water leaking into the hull and it was coming in through the pulled rivets of the combing. The deck camber, or it's shape, is designed to shed water to either side of the boat and so when you have a flat it means that there is a problem with the support foam that should be addressed before reattaching the combing because the combing helps the deck to maintain its proper curvature. If you caulk the gap it might hold for a while but the first time you kneel or stand or sit on that part of the deck and the support is not there it could start leaking or cause a well in the deck where water can collect and leak into hull.



Minas man