Hull to Deck seam.

[makedevine]

I acquired a CP16 last August and had to replace the forward and aft bulk heads along with the bunks. I made the task easer by splitting the deck and hull. I'm now ready to reattach the two, but one question comes to mind. Should I use 3M 5200 or go ahead and epoxy the two. My train of thought is that by using epoxy there will be a stronger joint and the water infiltration will be stopped once and for all. My understanding is the hull to deck joint is there just to make manufacturing easer and is somewhat a weak spot in the design of any fiberglass boat. Any thoughts on this would be appreciated.

[wes]

I recommend 5200. That's how the factory does it. It is strong as hell, it remains flexible forever so the seam can flex without cracking, and it's the right consistency to fill any gaps or uneven areas along the joint. 5200 is the gold standard solution for this application - I would not re-invent this particular wheel.

- Wes

[Salty19]

+1 on 5200.  Don't forget the rivets or bolts between the flanges as well.  Apply strong tape to the flanges after cure and apply the rub rail.
This area is about the only spot you'll want to use 5200 on the entire boat.

[buckaroo]

At Home Depot I found some aluminum waterproofing tape that is great stuff.  It's backed by butyl, and insanely sticky, but removable if need be.  I wonder if it might be a good replacement for the white duct tape?  I know conventional wisdom says that the duct tape doesn't really do anything, but swapping it out with a butyl-backed waterproofing tape might add an extra measure of watertightness should the 5200 fail because of age or improper application.

[Salty19]

As long it's thin, allowing clearance for the rub rail to fit, that sounds like a great idea!

[buckaroo]

Yep, it's not any thicker than the duct tape. 

[Pacman]

3M 5200 is a very strong polyureathane adhesive.

It is best for permenant installations and something stuck in place with 5200 will be almost impossible to remove without damage.

I have heard of a product called Debond that is said to allow things stuck together with 5200 to come apart but I have never used it.

A deck to hull joint bonded with 5200 will be very strong indeed.

[wes]

I would like to offer another perspective here. Having discussed the duct tape issue with Hutchins when I replaced my rub rail, it's clear that it was just a manufacturing convenience to allow them to apply the rub rail without having to wait for the 5200 to cure. It doesn't serve any long term purpose and certainly doesn't keep water out. The hull to deck joint is an ongoing maintenance point - you will want to inspect it every few years and may need to get to it in case of a leak. Personally I would not want it covered with that foil backed butyl tape; you'll just have a more frustrating time getting it off to expose the joint later.

On the subject of Marine Formula by Debond, it is a miracle cure for removing 5200 when you need to. I went through three cans during my 19 renovation. Best way to buy is direct from the manufacture at www.marineformula.com. My best advice though is NOT to use 5200 in any application where you might need to remove and rebed in the future. 3M says it's "permanent" and they aren't kidding. Perfect for hull to deck joint, not so good for almost everything else. I like 3M 4200 for deck hardware.

My 2 cents.

- Wes

[makedevine]

I'm not trying to reinvent the wheel, but with so many complaints about water leakage at the split line i would like to fix it once and for all. If 5200 is what is used at the factory it must not be the answer since it broke down showing there is flex in the joint. Not a single rivet I removed showed signs of stretch, but the split line did have a bulge between the rivets( rivets were 6 inch on center, i will double the rivet count to 3 inch on center when I reinstall the deck).  After the 5200 breaks down the water will find a way to get in again. With epoxy the joint will not move over time. The deck to hull joint has been the weak link in the chain since fiberglass boats first floated.  The joint is one of the first places your to look at when surveying a boat, power or sail.  The reason for that is theres always flex in the joint . Check out how many times a post was wrote about water infiltration at the joint.  5200 would be a great interim fix if you didn't have the joint apart!  And I"m still in wonder what the tape over the rivets is for, you can"t count on it for any sealing effect!  If you could fix two defects once and for all would you do it? (deck to hull joint flex and deck to hull water leakage). IMO the use of 5200 during construction of the deck to hull joint is a cost saving measure. The only down side i can forsee is if you have to rework the interior of the boat at a later time!  Would it be worth it to never had to re bed this joint? That's just my openion but I would like to hear other openions.

[Pacman]

Makedevine, There is nothing wrong with adding more rivets but 5200 is the strongest bonding agent I have ever used and I highly recommend its use in the hull to deck seam..

Wes,  Thanks for your comments on Debond and 4200.  I appreciate hearing the voice of experience on things like this.

Also, where sealing is needed but not adhesive properties, I have found that DAP elastomeric sealent without silocone is excellent.  I used it on the chainplates of my Contessa 26 and it has worked better than a long list of "marine" products that I tried over the years.

I first used it on the gutters of my house and it worked well, even in the Florida sunlight, so I tried on the boat.  Best sealent ever and cheap too.  Just don't get the one with silocone in it.

[gabi]

on my boat somebody caulked the upper part of the rubber rail to the boat edge with some sort of clear sealant/ maybe silicone?
it doesnt look to prety, but it does the job for now

i dont know how long is been there, or how long is gonna last but it keeps the water out