Fillet failure.

[skuthorp]

I sail a 12ft ply dinghy designed in 1974 and likely built a year or two later. It has been in our club since new. Over the last season or so I have been puzzled by the leaking of water into the side tanks. I checked the fillets and they seemed all intact. I even did a few repairs two seasons ago just in case. But last week I had cut myself and my hand was bleeding as I mopped out the tanks, and I noticed bloody water filtering through the FG fillets. She was leaking from the cockpit, not through the hull.
Can I repair the fillets with a smear of epoxy, or do I need to rip them out and replace them?
I sail in salt water.

[Larks]

I sail a 12ft ply dinghy designed in 1974 and likely built a year or two later. It has been in our club since new. Over the last season or so I have been puzzled by the leaking of water into the side tanks. I checked the fillets and they seemed all intact. I even did a few repairs two seasons ago just in case. But last week I had cut myself and my hand was bleeding as I mopped out the tanks, and I noticed bloody water filtering through the FG fillets. She was leaking from the cockpit, not through the hull.
Can I repair the fillets with a smear of epoxy, or do I need to rip them out and replace them?
I sail in salt water.

A smear of epoxy won’t give you the strength that the fillets were there to provide Jeff, and any epoxy pushed down into the crack likely won’t have clean and clear surface to bond to effectively. If you want them to hold you’ll need to replace them. Though if they are awkward to get to (ie to get them completely ground out): you could sand them back enough to provide a good glue surface on both sides of the fillet and on the fillet face and build a higher layer of fillet over the top. It wouldn’t be pretty and it wouldn’t be ideal but it would give you more strength and seal than a smear of epoxy.

[wizbang 13]

A crack in a fillet of a dingy built 50 years ago is not a failure, imo.
Anyway, yes we like to advise correct repairs not smears.
photos help though

[Hugh MacD]

50 years ago that may well have been built with polyester, not epoxy. I'd definitely grind as much as I could and perhaps use judicious heat to help loosen the old bond further. I've found poly comes off pretty easy with a heat gun.

[skuthorp]

Thanks for that everyone, I really knew there was no easy solution. Of course if the material there has failed what of the rest of the joints? I had a 1963 built mast fail for that reason, and when I checked the other spars the glue had just turned to powder.

[robm]

Perhaps a bit of fiberglass tape and epoxy over all? This would seal the existing fillet, and add strength as well.

[sp_clark]

Perhaps a bit of fiberglass tape and epoxy over all? This would seal the existing fillet, and add strength as well.

Prolly not a Good Idea. Just adds weight, everything underneath is already suspect, you're just spending money & labor on top of an 'iffy' base layer that may fail a year from now or a week.