My 1986 MacGregor 21 has large mouthed deck mounts/covers that are riveted with very large rivets. They constantly leak. I've tried to pack them with butyl, I've tried to seal the edges and the rivet contacts with silicone and still have pretty decent leaks. I'm skeptical about using sealants other than butyl because of the worry of crevice corrosion. I've heard silicone can be a good choice because it is flexible enough to handle the loads from the chainplates under tension and not under tension when taking the mast down.
I'm just looking for any advice on the best way to seal them or replace the covers with a better cover that doesn't have huge gaps between it and the chainplate.
I've also just thought about cutting holes underneath the chainplates in the cabin mold to allow any drips to go into the bilge rather than onto the settee cousions.
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Chainplate gaps
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jordans1984
- Posts: 7
- Joined: Tue Nov 14, 2023 9:03 pm
- Sailboat: MacGregor 21
- Location: California
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OverEasy
- Admiral
- Posts: 2989
- Joined: Mon Sep 28, 2020 11:16 am
- Sailboat: MacGregor 26X
- Location: NH & SC
Re: Chainplate gaps
Hi Jordan1984!
On our Mac26X I had a similar concern.
In our case I drilled off the rivet heads to lift the chainplate cover and pushed in the residual rivet sections.
Cleaned it out as best as I could with picks and stiff water bottle straw brush and a bit of solvent.
Packed back as much as physically possible with butyl putty.
Then re-riveted with slightly larger Stainless Steel rivets using a HD riveter (Stainless rivets can be a bit stiff).
Ours haven’t leaked since and it’s been a few years now ( knock on wood).
Personally I’ve always been disappointed by any silicone sealant as they tend to fail at the metal surface interface intermittently and are horrible to adequately remove later. So I sorta prefer the butyl putty caulk as it has repeatedly lasted for decades without fail while still allowing me to easily adjust compression or remove components when needed without being a pita. Clean up is simple and easy too!
(Whereas silicone seal always seem to get every where one doesn’t want it
)
Hope this helps.
Best Regards,
Over Easy
On our Mac26X I had a similar concern.
In our case I drilled off the rivet heads to lift the chainplate cover and pushed in the residual rivet sections.
Cleaned it out as best as I could with picks and stiff water bottle straw brush and a bit of solvent.
Packed back as much as physically possible with butyl putty.
Then re-riveted with slightly larger Stainless Steel rivets using a HD riveter (Stainless rivets can be a bit stiff).
Ours haven’t leaked since and it’s been a few years now ( knock on wood).
Personally I’ve always been disappointed by any silicone sealant as they tend to fail at the metal surface interface intermittently and are horrible to adequately remove later. So I sorta prefer the butyl putty caulk as it has repeatedly lasted for decades without fail while still allowing me to easily adjust compression or remove components when needed without being a pita. Clean up is simple and easy too!
(Whereas silicone seal always seem to get every where one doesn’t want it
)Hope this helps.
Best Regards,
Over Easy