Roof rail leaks

Pandion · Posted: Mon Jan 28, 2019 2:06 pm Post subject: Roof rail leaks

Apologies if this has already been covered, but I have been getting leaks at the points where my roof rails are attached to the cabin top. The leaks have been showing up at the corners of the wooden handrails inside the cabin.

As a temporary fix, I have caulked around the mounting points on the roof with 3M 4200, which seems to solve the problem for a time. I'm thinking the correct long-term fix will be to remove the roof rails and interior handrails, scrape off the dried 4200, and rebed the rails using Boatlife caulk or butyl tape.

Does that sound like a good plan? Have any among you attempted this repair?

Andy

journey on · Posted: Mon Jan 28, 2019 3:17 pm Post subject:

Did it with 3M 4000. Has stayed dry for 14 years.

Boris

thataway · Posted: Mon Jan 28, 2019 3:56 pm Post subject:

Yes, you need to remove the rails. If that area is cored (most likely) you need to undercut and remove the balsa core (Likely wet). I would use 4000 for sealant. It was most likely not originally 4000 or any other 3M product. The butyl tape has to be kept under pressure. The 4000 is going to be better at stopping leaks and not allowing the bolts to vibrate loose.

Pandion · Posted: Mon Jan 28, 2019 4:24 pm Post subject:

Thanks guys!

ssobol · Posted: Mon Jan 28, 2019 5:04 pm Post subject:

Just remember that the forward handrail bolts also hold the overhead self at the front of the cabin. If it is like mine you may have equipment up there that needs access (mine comes done at least once a year). Might not want to make the front bolts too secure if you ever need to remove the overhead shelf.

Pandion · Posted: Mon Jan 28, 2019 5:26 pm Post subject:

journey on · Posted: Mon Jan 28, 2019 6:29 pm Post subject:

My memory isn't that good, but I don't think so. You'll find out after you remove the first bolt.

I don't remove the shelf often but remember, one would seal it every time. I just reach in and drill any holes with a right angle drill.

Boris

thataway · Posted: Mon Jan 28, 2019 7:11 pm Post subject:

Generally both the 22 and the 25 (which Boris owns) have core in the part of the cabin roof where bolts are attached. You can hold the shelf in place with a temporary strut from underneath when removing the bolts. I have done this in several bolts--not a problem. I used 2 x 2 lumber and some wedges against the floor--there was no discernible movement of the shelf when I removed the screws.

My current 25 has core in both the upper part and lower parts of the roof. My 2003 C Dory 25 did not have core in the upper part of the roof;. (Upper part was that which is raided up for "head room", in the center.) A 2002 boat should have core--and that should be sealed.

Interesting, I have never removed the upper shelf in any of the 5 C Dorys I have owned--but have made the mounts so that any electronics could be easily removed for service if necessary. The reason was I didn't want to compromise the seals for that railing once properly bedded and get water onto the electronics mounted there.

lloyds · Posted: Mon Jan 28, 2019 10:42 pm Post subject:

I have had really good luck with butyl tape I purchased from Sailrite. Easy to use and not messy like caulk.

ssobol · Posted: Mon Jan 28, 2019 11:00 pm Post subject:

My rails are also sealed with butyl tape I got from some place recommended on this site.

On my boat the shelf is wedged into the roof. There is a slight lip that the shelf fits in. The clearance on my shelf is such that it can only be taken down on pretty warm days when the boat has been sitting in the sun for awhile. On insufficiently warm days, the roof contracts enough that the shelf is held in place by an interference fit and would require a pretty big hammer to release it.

I suppose that if I wanted to I could resolve the fit problem with the shelf by trimming the edges a bit. This never occurs to me at the times I have the shelf out though. Maybe next time....

FWIW, I have a cooler rack for the transom that also can only be installed or removed in the summer when the hull expands in the heat.

Hunkydory · Posted: Mon Jan 28, 2019 11:48 pm Post subject:

Our 22 CD didn’t start leaking until our 2016 SE Alaska cruise. I think the leaks started due to the stress from using the rails as tie down supports for our rubber dinghies & the Mokai. The only through bolt area leaking was the starboard side furthest forward holding the over head shelf. On the cruise I temporarily stopped the leak with 4000 around the top side through bolt. When back home, I took them all completely apart & noticed several nuts were more loose than they should have been. Following removal I cleaned well & resealed with 4000. No leaks since & it was 16 years before the first leak appeared. I also used 4000, when installing four additional handrails several years ago. I think over time my leak started from the strain of the tie downs & the nuts loosening, which seems to be another item worth checking periodically.

Jay