So I removed the "L" profile teak cover strip on the underside of the deck hiding the nuts on the genoa track bolts and noticed that one of them and only one of the 30 has a rust stain around it and seems to have wet the teak cover strip below.
Obviously it's a lot of work to remove 30 bolts, over drill every hole, fill with epoxy, re drill and caulk the new bolts whilst affixing the track again. Especially when 29 of them seem to be ok and might be best left alone on the if it ain't broke principle.

What do you guys think of removing only the suspect bolt and then drilling only that hole from below with an oversize bit until it hits the underside of the track then filling with epoxy. After that I would drill down from the top with the right size bit for the bolt and then before inserting the bolt insert Sika 291 from the top and the bottom. Obviously I need to be careful not to drill significantly into the underside of the track and also the caulking job may not be totally effective in which case the bolt may leak a little but this doesn't really matter as long as the core of the deck is isolated and sealed with epoxy. Hopefully in that eventuality after finishing the job I would keep an eye out and see/rectify any drips from that bolt.

Comments please?

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julesmoto said..
So I removed the "L" profile teak cover strip on the underside of the deck hiding the nuts on the genoa track bolts and noticed that one of them and only one of the 30 has a rust stain around it and seems to have wet the teak cover strip below.
Obviously it's a lot of work to remove 30 bolts, over drill every hole, fill with epoxy, re drill and caulk the new bolts whilst affixing the track again. Especially when 29 of them seem to be ok and might be best left alone on the if it ain't broke principle.

What do you guys think of removing only the suspect bolt and then drilling only that hole from below with an oversize bit until it hits the underside of the track then filling with epoxy. After that I would drill down from the top with the right size bit for the bolt and then before inserting the bolt insert Sika 291 from the top and the bottom. Obviously I need to be careful not to drill significantly into the underside of the track and also the caulking job may not be totally effective in which case the bolt may leak a little but this doesn't really matter as long as the core of the deck is isolated and sealed with epoxy. Hopefully in that eventuality after finishing the job I would keep an eye out and see/rectify any drips from that bolt.

Comments please?

Personally, given that it is only one bolt I would remove that bolt, clean it up with a wire brush, load the threads with either butyl or simpsons sealant, reinstall and clean the excess that will have oozed out on reinstallation and keep a close check on it to see if the leak persists. If it does then the method you propose would be my next attempt.

I agree with the butyl. But don't seal the underside like in the photo. Any water that leaks past the thread needs a place to go.

If it is a cored deck, I would take the extra precautions as you describe. I'd use plain epoxy to wet the hole out before using a epoxy filler mix. You will have to have some way of preventing the epoxy filler droop or fall out then fill from the top to avoid voids. If solid deck then Bob's way would be simpler. I am facing the same thing but have a few more than one bolt to seal, not quite sure how many are leaking plus I have stanchions to fix as well.

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john24 said..
If it is a cored deck, I would take the extra precautions as you describe. I'd use plain epoxy to wet the hole out before using a epoxy filler mix. You will have to have some way of preventing the epoxy filler droop or fall out then fill from the top to avoid voids. If solid deck then Bob's way would be simpler. I am facing the same thing but have a few more than one bolt to seal, not quite sure how many are leaking plus I have stanchions to fix as well.

Thanks everyone for your answers.
Yes it is a ply cored deck at that location and yes the Megapoxy 1to1 filler which I use is unlikely to wet out the edge of the ply sufficiently without putting some plain less viscous epoxy around the hole with a paintbrush 1st.

Also yes the filler does have a nasty habit of leaving voids and I'm not quite sure how to avoid that because I don't fancy filling from the top and getting it all over the alloy track. I tried a syringe previously but it was a bit thick for loading and dispensing.I guess I will just bung it up there with my gloved finger and perhaps jiggle around with a screwdriver from below before taping over it. Not a lot of work really with 1 bolt hole.

I have recently done a stanchion and as there are only 4 bolts involved I took the whole thing off and did it from the top. I also used butyl tape rather than 291 since I was doing it from above with a wide contract area and I and I also chamfered the holes a bit from above to help with compressing a bit more butyl tape into the relevant area.

Ok so did the first steps today over drilling the hole from the underside coating with free-flowing epoxy then putting Megepoxy filler in a syringe and injecting that in from the top. Contrary to my recollection from previously it works fine in the syringe. Will drill out the hole tomorrow and seal with either butyl tape or 291 I haven't decided which yet. Will be conscious to only seal at the top to let the bottom drain if any water does get through as per @Ramona. Two-person job because I don't want to rotate the screw once the sealant is in.

If you use Butyl you can rotate the screw for a couple of days after and it will reseal.

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Ramona said..
If you use Butyl you can rotate the screw for a couple of days after and it will reseal.

Thanks. Might just do that as I would like to get it done tomorrow then go for a sail and I will be by myself

I'd be worried about how long it's been leaking and how much rain water has been getting soaked up by the plywood, if the ply is wet and soft it wouldn't be ideal for resealing

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bullrout said..
I'd be worried about how long it's been leaking and how much rain water has been getting soaked up by the plywood, if the ply is wet and soft it wouldn't be ideal for resealing

Yes that's what I was worried about although it seems that Northshore (impressively) flow coated the inside of the existing holes. However as I had to bash the bolt out I ended up damaging this finish but when I over drilled it out all appeared dry. My epoxy filler job went slightly up into the track which I didn't think was a problem when I drilled down from the top with the correct size bit for the new bolt.

Unfortunately I had forgotten about the track insert insulators which are wider and I needed a bit 2 mm wider to drill out that first little bit of length from the top. I had assumed that the insulators would not extend down past my filler through the track but unfortunately I must have filled more of the track than I realised.

I didn't realise any of this until I had already put sika on the bolt and insulator and in the top of the hole. I then tried to expand the hole in the first 8 mm by using the undersized bit that I had. I didn't drill far or wide enough as I was dead scared of going back down into the ply so ended up cracking the only insulator I had trying to screw it down hard. Of course Sika mixed with drilled out epoxy chaf and it ended up being a complete balz up.

Will be redoing it tomorrow with an 8.5 mm bit and new insulator.

Wish I had used the butyl tape now.