Thin Decks

[Paul8753]

Every season I contend with a problem of thin decks that crack. Built on the thin side, this boat has a bit of flex that eventually cracks. I gelcoat it but this is only a cosmetic repair and does nothing to make it really go away. I can cut away the headliner below and get at it that way? How about drilling holes and injecting expancing foam followed by the final gelcoat repair?Comments...

 

[Ed A]

NO NO NO!

dont use expanding foam. when foam is injected to a space of known volume you can control how much you put in. when you dont know the space the foam either does not fill the void or overfills it. when that happens thing that are bad start happening, Like the deck raises up a few inches and breaks or the inside expands and breaks. that stuff is wild. try taking a paper cup and spraying it just full of foam, not too full. betcha cant.if the deck is flexing and hollow you may drill holes and inject epoxy, that wont expand and break the deck. then repair the little hole. but the bad news is that will not usually stop the problem. the cracks may be from walking on it but more likely the boat is flexing a bit and cracking the gell coat. it is important to try to stop any water from getting in and rotting the core.

 

[Paul McGhee]

Stiff Decks

The classic way to stiffen a deck section is to laminate a semicircular fiberglass beam underneath it.Typically, a cardboard tube is cut in half lengthwise and taped to the underside of the deck to act as a form. Then, overlapping strips of fiberglass cloth or roving are epoxied over the tube, usually 3-4 layers. If the area is large, you would lay up more than one beam.The problem, particularly with a smaller boat, is getting access to the area that needs reinforcement.This doesn't fix a deck that's spongy because the core is rotten. This stiffens a deck that is too springy because it's too thin.This is such a typical repair that you can pick up almost any book on fiberglass repair and find an example: My favorites are the Hinckley Guide to Yacht Maintenance, Don Casey's excellent book on fiberglass and hull repair, and the West System epoxy repair guide.