Wet beds, mildew, rust stains in the cabinets, water stained and rotting paneling, stained headliners, rotted deck cores with soft spots . . . these are just a few of the damages caused by deck leaks.

Let's begin with the fact that nearly all boat decks are cored with materials like balsa, plywood and foam. The coring is necessary for several reasons, including strength. But the cores are also good heat insulators too, and there's nothing wrong with the basic concept of coring a deck except when water gets into it. Leaking decks usually have two basic causes:

Improper design, construction and installation of hardware.

The cores must be designed to be completely water proof, followed by the rule that nothing must ever be done to the deck to damage that water proofing. Of course, people find it necessary to attach things to their decks, and that's where the second basic problem arises. They drill holes in the deck and screw things down without realizing that what they are doing is creating a point of water entry into the core.

If you own a used boat, you may find yourself the victim of the former owner's ignorance. If you bought your boat new, pay heed to what you should and should not do as respects adding hardware.

Pre Existing Holes About 75% of boats have holes drilled in the decks, holes that are revealed by the removal of hardware, and holes that were never even properly repaired. Whether there are existing holes in the deck, or you plan to remove a piece of hardware, the first thing you must be aware of is that you just can't fill the hole with putty and forget it. Fiberglass expands and contracts with heat and cold, so that just filling the hole with putty won't seal it. The putty will loosen and the leaking will begin.

 

If you have existing holes, or holes with open seams around the filler, they need to be repaired immediately.

Drill a total of four more holes on the under side in a rectangular pattern, bracketing the area. You can just take a small drill and run it straight through the deck from the hole(s) that you're going to fill to locate the area from the underside. Temporarily cover the holes on deck with silicone sealer, and then wait at least two weeks for the core to dry out. Once the core is dry, then take a drill that is just slightly larger than the old holes and drill them out to get a nice clean surface to which your epoxy paste can adhere to. Using a nail or something similar, work the epoxy paste down into the hole until the hole won't hold any more. On the surface, pile the epoxy up a little to make a slight hump that you'll come back with a razor blade and slice off nice and smooth after it has cured. Its not likely that you're going to go to all the hassle of gel coating the finish, so you can just touch up with a dab of white enamel.

Railing Stanchions The most common point of leakage is from stanchion bases. For some strange reason, the boating industry has never seen fit to manufacture stanchion bases that are wide enough to resist the tremendous amount of leverage that is placed on the base by a 36" stainless steel pipe.

Notice that there is no core in way of the point of attachment, an area of solid fiberglass called a 'boss." This eliminates any possibility of water getting into the core, and provides a very strong point for mounting. Obviously, if your boat is not built this way, there's nothing that can be done to change the original design.

Repairing Leaking Stanchions Leaking stanchions can be repaired if you have some access from the underside. Unfortunately, in most cases you have to tear the interior of the boat apart to get that access, which accounts for the reason why deck leaks are rarely ever repaired. The leaks just go on and on until the interior is ruined and the boat gets junked, or some poor fool comes along thinking he can restore it.

There is only one way to effectively stop the leaks, and that is to rebolt the stanchion bases, and to add aluminum doubler plates to the underside if it doesn't already have them. Its the lack of doubler plates that is probably part of the problem in the first place, and unless you resolve this, nothing short of strengthening the mounting will help.

If the core is deteriorated around those bases, then what you are looking at is a repair job of major proportions, and one that almost no one will foot the bill for. If there is no core in way of the bases, then all that is necessary is to remove the headliner or whatever is covering up the fasteners on the inside and remount everything. The thing is, if they were bolted on in the first place, they are not likely to be loose, meaning that what you've got is probably screwed on stanchions. The only way to remedy this is to bolt them on.