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Update on my recent (old) Sunfish purchase, huge gaps where cockpit meets Hull (pictures included)


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Hi guys, so a few days ago I posted a few questions about my recent sunfish purchase and a rather "sketchy" tiller it came with.

You guys were super helpful and pointed me in the right direction to learn more about what parts I need, and where to get them.

What I ended up doing was removing that sketchy tiller and making my own makeshift tiller and extension with a broom handle (lol) It worked for the week, and I had a great time sailing this old boat.

It was fairly leak free, the bottom had some damage, which I fixed up quickly with Marine goop and fiberglass patches, and it was bone dry after a day of sailing.

However, the second day I was doing some capsize practice and that's when I noticed the leaks. The entire hull was full of an inch of water (or more!) and it weighed a ton. The performance was also sluggish and I couldn't figure out where all this water was coming from until I did an air test and put my hand in the cockpit. Thats when I noticed huge gaps around the entire edge of the cockpit.

What I imagined happened was water just pooled into the gap while the boat was laying on its side in the water and it took in water until it matched the water level outside. You can even see this in the port photo because of all the rocks and sand in the gap (that was the side I capsized on)

Based on the Sunfish timeline PDF, I have a very old Sunfish. Probably 60s or 70s. The bailer is still metal, and there is no ID plate at all except for a very worn little stamp in the cockpit itself (see front picture)

The TLDR: What can I do about these gaps? Someone in another thread recommended biaxial tape, and another recommended sealing it with caulking.

As for the rest of the ship, there is very little dmg or leaks on the top deck, and the bottom seems leak free after I did the fiberglass patching and marine goop sealing

I don't want to go all out with expensive fixes or fancy professional fixes - this boat is old and not pretty - but it still sails amazingly well and takes in no water. (Unless it capsizes)



New Member
Fairly old - probably 1965-1975 judging by the info I could find on Sunfish Timeline PDF.

Deck hardware is decent, a lot of it is new/replaced. The mainsheet ratchet is brand new. The cleats are in good shape and the mast pole also has a cleat.

Damage on the deck is very minimal and I've seen no leaks using the air test.

The bottom and keel was in rough shape due to the horrible trailer that I imagine it was bounced on for years, but I patched that up with fiberglass/marine goop. There is no leaks on the bottom now.

The gaps in the cockpit are now the issue. Is it as easy as just caulking it and then taping it up with something like biaxial tape?

I think cleaning up the joint between the cockpit and deck as best you can (wire brush / sanding), wipe it clean with acetone and installing a good bead of thickened epoxy or maybe 3m 4200 would probably do the trick and wouldn't be too expensive.


Well-Known Member
Biaxial fiberglass tape requires bonding to the surfaces with resin. :oops:

Biaxial tape will make a strong angular support for the deck that surrounds the cockpit. It will strengthen a deck that already shows surface cracks in its thin layer of gelcoat. If the expense is too much, overlapping 6-inch squares of regular fiberglass (placed diagonally) will also work.

Brush two coats of resin over the fiberglass material, throw away the brush and gloves, and you're done! :)


New Member
I repaired my 69' or 70' by hanging it upside-down, ground down the gelcoat and the deck. I thickened up epoxy and created a fillet where the cockpit wall meets the deck. Then I layed up 3-4 layers of fiberglass cloth (not the chopped stuff). It is very strong and should be waterproof.


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New Member
Thanks guys! The tips and photos definitely give me some very good ideas going forward.

When it comes to Fiberglass and Resin, is there any type of Resin that works better for boats? Specifically, the gaps in the cockpit, or is it generally all the same?

I plan to go with LAWilliams idea with the 3M poxy to fill in the gaps first, and then I'll copy Wolo4's pictures and fiberglass the inside with a few layers after
If you’re using fiberglass, then you want to use polyester resin or polyvinyl resin. If you are using epoxy, there are different kinds of fiber matting that doesn’t use styrene as a binding agent.