Cabin to Hull joint - is there supposed to be a gap?

[handmeawrench]

Hi again, c-bratistas. I have another question and am seeking your wisdom and experience.

The set-up: 1987 c-dory 22' Angler. Second owner. Previous care and maintenance unknown (but a bit suspect based upon her appearance).

At the joint between the cabin bulkhead and the hull, this particular c-dory looks like it was caulked at some point, but the caulking is gone. It is not water tight now. The same is true for the forward cabin bulkhead (molded piece that forms the shape of the cuddy cabin seating).

Both of those bulkheads have a threaded plug indicating that they should be water tight, but the caulking is gone and water can most certainly find its way through both of these joints.

I am considering laying in a fillet of epoxy there rather than caulk (run a bead of epoxy into the inside corner joint, then shape it with a tongue depressor so it makes a nice radius). This would not only seal it up good, but would add strength to the structure.

But here's the thrust of my topic: This is my first c-dory and for all I know maybe it is deliberately NOT epoxied there to allow for movement. Epoxy could create a 'hard spot' in the hull which might have negative effects.

Long story short - what do people use to seal the joint between the bulkhead and sole?

WHEW! Thanks for sticking with me on that one. And thanks very much for your experience and advice.

[Sunbeam]

I'm not sure which forward joint you are describing, but on the after one that joins the cabin wall (the one with the cabin door in it) to the hull: Mine is tabbed to the hull with fiberglass/resin, and does not look like it has been changed since it was built. I think you are right to always question whether or not a particular joint should be rigid, but in this case, I would say it should be, as this seems like a bulkhead with some structural qualities. I think I would tab (i.e. add fiberglass tape) rather than just a fillet, myself (that is, I would make a fillet, but as a curve-support for the ensuing tabbing).

Just so you know, later 22 Cruisers (~2007 onward) have a permanent/raised/flat cockpit sole, and that is (from what I have read) caulked to the cabin bulkhead. But even on those boats I would imagine that the "real" joint (hull to bulkhead, below the raised sole) is tabbed.

Sunbeam

[ghone]

From what I can tell, on my 2011, the flat floor looks like it has a vertical front to form a "bucket" or tub type wall in front of the bulkhead. I think the new floor/ cockpit has raised sides all around where it meets hull and cabin This would not allow water into the cabin. The sealant visible is then backup to a structural joint. Inside the bulkhead is a glassed join about a foot up. i will maintain the sealant when needed with white 4200 or Lifeseal white.

[ssobol]

According to the previous owner of my 2008 CD-22 there was a gap between the outer cabin wall and the flat floor of the cockpit. This would collect water which would end up inside the cabin either from splashing water into the cockpit or from the rain. When they added the flat floor, they removed the sump and pump that was just below the main door on the inside. It took him awhile to figure out where the water was coming from.

The PO got a couple of tubes of 5200 and "caulked the **** out of it" from one gunwhale to the other. He did a nice job and it looks like the boat was built this way. No more water in the cabin.

[thataway]

I cannot comment directly on the 1987 boat, since that was a year of transformation form the original C Dory to the modern hull. The assumption is that the aft bulkhead is not removable, and thus was tabbed in place initially.

A filllet is a filler between the hull and bulkhead and gives a radius for the layers of glass to avoid a sharp bend in the glass. When we were fiberglass boat building, we cut foam trapezoids inserted between the hull and bulkhead, for the basis of the fillets. We then laid in the actual fillet with polyester resin and microballoons. (new construction) That was a small spacer off the hull (so the solid bulkhead would not press on the hull and make a hard point). The radius of the fillet then was the basis for the decreasing width of the fiberglass strips :6", 4" and then 3" which tabbed the bulkhead to the hull. I feel that just a fillet does not give good support, nor spread the load out enough, and in handmeawrench's boat would be the way to go.

When we put the new floor in the 25, we tabbed it to the hull with a fillet, but where the floor met the bulkhead, we caulked it. I would do the same on the more recent C Dory 22's which have the raised tabbed in floor--caulk it to the bulkhead as in ssobol's boat.

I believe that both bulkheads--aft and the foreword, which is molded with the platform for the "V" berth and head platform- are structural. Again--I don't know exactly how the 87 angler was initially made. However, in more recent boats (1992 to 2007) The forward bulkhead should be glassed in. The aft bulkheads are cored--initially with balsa, more recently with foam.
Again the sandwich gives more strength--and tabbing in increases this structural strength. Also the core can get wet and rot (I am aware of several boats where this has occurred). To keep water out--again tabbing works well over the fillet.