How to repair cracked coaming?

Thread starter #1
Hello Sunfish friends:

My recently purchased 'fish came with a crack in the coaming, starboard side, that I managed to make worse while getting on the trailer it at the end of a recent trip to the lake.

Not a big deal, but it keeps me from putting my hand there, and I'm worried a first mate might put weight on it and crack it straight through.

Any recommendations for a repair?

Or should I look into replacing the coaming? How big of a job is that? (The boat has inspection ports nearby.)




Active Member
Super easy job to remove and put some cloth and mat on the back. It's
broken because the coaming ends are a major stress point that keeps
the hull from flexing, (less).
Super easy, yes, but I wouldn’t remove the coaming or you may end up with a much bigger job getting it back on. I took mine off to paint the deck. The screws left big holes. A RIVNUT gun is expensive and proper size rivets were a pain to find. Then I had to fill in and redrill all the holes...
I’d tape off the area and use Marine Tex to repair. Maybe clamp it to hold the shape, use plastic wrap over it to get it as smooth as you can. Sand to shape. You can repaint the whole splashguard or just touchup the repaired area (or not!)


Active Member
It's a structural repair for broken fiberglass so Marine-Tex will
not work. You can get a Rivnut gun if needed for about $45
at Harbor Freight. If the Rivnuts are pulling out they need to
be replaced anyway but removing the screws should not result
in a problem 90 percent of the time.


Well-Known Member
It looks like there's not much material missing. :) Based on the edges, one fragment (shown) can be restored within the repair.

Fullscreen capture 972019 71722 PM.bmp.jpg

I'd mix up some two-part epoxy, and clamp the pieces together. What fragments are missing can be restored with Marine-Tex. Ahead of the repair see if some spaces can't be filled, then add some trimmed fiberglass cloth (or mat) and sand down the excess. Fill small voids with Marine-Tex.

Paint. Sail. :)



Active Member
Splash Rail is structural, it keeps the hull from flexing. That's why the last two or screws on each end often pull out and the hull seams often pop in that area. If you want confirmation remove the three screws on each end and go sailing in chop.
Watch what happens to the gap between the hull and the Splash Rail.


Well-Known Member
Most revealing was a video I took a few years ago, and posted it here. Some misadventure had torn one half of the screws securing the splash guard out. Sailing in easy winds showed the end flexing up and down about 1-1/2 inches. :eek:.

Add to that my borrowed blue Sunfish, where the splash guard was missing. :confused:

It's also possible the mast step and daggerboard trunk would take a lot of twisting stress when sailed in heavy weather. So yes, I consider it structural.