Hull to deck joint 34/35

[Sefuller]

I finally tracked a persistent water leak to the fasteners attaching the hull to deck. On our 34, there are through bolt/nuts about every 6 inches or so. Not sure what if any sealant is in the joint. As I looked closer during a three hour rain today, many of the fasteners are weeping slightly and a few are dripping. I have been planning to replace the rub rail anyway, so would plan to tackle this at the same time, but not sure exactly what to do - pull out all the fasteners and rebed them with butyl? That alone will be a daunting task as the nuts are not easily accessible and there are lots of them!

 

[jibes138]

I'm sure the joint is sealed but 30+ years down the road..... best way to fix a leak is from the outside and removing the screws is the way to go but sounds horrific. You might want to try just using sealant on a putty knife to cover the screw heads under the rub rail. Try a few and see if it works. If they are flat head screws this might do the trick without pulling them out.

 

[Sefuller]

@jibes138 I replace a section of rub rail on the front of the boat last year and my recollection is they are pan head screws. I agree it will be a chore, but I really only want to do this once, and I will have all winter to do it I am resigned to removing all the screws, my dilemma is whether to try to clean old sealant out of the joint and put new sealant in.

 

[jibes138]

Without removing the whole deck how could you remove the sealant from the joint? Other than the screw holes I would take a 5 in 1 tool and scrape the edge of the joint out a bit then apply a bead of 3M 4000 or equivalent. That should be good for another 20 years. Like caulking a sink or a bathtub. I see you're in Milwaukee, winter will only last about another month so you better hurry up :>)

 

[jssailem]

I see your in Milwaukee and winter will only last about another month

Then a month of summer and sailing. Then Winter again. Hurry you don't want to miss it.

 

[Jim 5757]

What type of joint is it? Our Morgan 28 has an outward-facing flange. They used 1/4" sheet metal screws and some hard epoxy sealant which was cracked in many places. Removed the screws - 4 ft at a time- and cut through the joint with a circular saw to clean out the joint. Refilled joint with 5200, replaced screws. Done! Rub rail doesn't seal the joint only protects it.

 

[Golden Road]

I'm assuming the 34 and 5 have a "shoe box" type hull deck, i.e deck laps over outside of hull. If so, I'm your man, as I am in the middle of doing my 30, which I found was assembled with pretty much no sealant at all. Clearly someone on the assembly floor had a bright idea to do things quick and clean. First thing: there is a lip along the top edge of the hull which was a 1/4" ply about 2" wide glassed in. On the 30 it ran on the forward 2/3 of the hull. Its purpose was/is to add rigidity to the hull so in bolting the deck ripples in hull are not formed. You will have to rip this out as it will be all soft and rotted. I replaced mine with strips ripped from a good quality fir 2x4, adhered with thickened epoxy, and the wood totally painted with epoxy. I then redrilled and and fastened with new 1/4 - 20's screws, about 150 required (find a Fastenal dealer near you) and lots of 5200 injected up into joint. Obviously, this is a 2 person job and it is messy. You want 5200 because 1.) It does not cure fast, 2.) Its strong as hell, and I'm never doing this again. Also, O'Days have a flexible hull and you want a sealant that is flexible. The rub rail replacement appears to be easy however I didn't want to drill a whole set of new holes as the rail already is drilled enough. So, save the old rub rail and you can transfer that hole pattern by over laying on new rub rail. A nice clean, warm house deck will help as the new rub rail is a bitch to handle and lay out flat. I also made backing plates to go under each rub rail fastener which supports the rub rail and further ties the deck-hull joint together (with another 150 #10 screws. But that's me, as I am aiming to make the boat blue water capable. Will send photos if you like..