The Rot Doctor


Subject: 1947 65' Grebe deck....
Date: Mon, 29 Jan 2001

Dr. Rot,
My wife and I recently purchased a 1947 65' Grebe motoryacht and wish to restore her to original condition. The previous owner started removing the original canvas decking material but didn't finish as the boat was shed-kept at the time. Since we've been unable to locate a shed slip locally, we're dealing with multiple leaks in every stateroom along the deck/hull seam.

I'm sure that's true!

Grebe's design called for water to flow along the toe rail from bow to stern, to be drained via flush scuppers located at various points along the inside of the toe rail. What we've noticed is that these "flush" scuppers (bronze) plug very easily, and there are no cutouts in the toe rail proper for the entire length. The deck appears solid in these areas, remarkably. What we're seeing is that water flows under the edges of the old canvas that remains anchored by the toe rail and leaks into the boat.

We will most probably restore the decks in canvas, and knowing this is not specifically your forte, would ask this: How do you recommend we approach these side deck areas that obviously see major water runoff/drainage? Do you recommend we canvas the fore and aft areas (large areas), and glass these side decks with your epoxy? How would these different materials blend?

Your comments would be most appreciated!

Gary & Sandy M.

Gary & Sandy,

It's possible to mix materials (that is, canvas in one area and epoxy/glass in another), but because of the different physical characteristics of the materials, appearance and junction seams can be a problem. If it were me, I would make a decision on a single covering for the entire deck area and go with that all over.

Canvas is traditional, and in '47 was about the best thing available. It's remarkable that yours is as good is it is...obviously a well-kept yacht. There are some traditionalists who will still use canvas, bedded in an adhesive compound and then painted. If the yacht was kept under cover I would say this approach would be satisfactory, but if the yacht is going to stay outside then I think one of the more modern approaches would be more enduring.

This being said, you have, in my mind, the following options:

1) Saturate the dry wood decks with CPES (Clear Penetrating Epoxy Sealer), and then use canvas bedded down in a deck adhesive. Then coat the canvas with CPES (2 coats), allow it to cure, and paint. Advantages: Relatively inexpensive and removable if repairs are required. Disadvantages: Not as sturdy as options that follow.

2) Follow the same steps outlined above except use a light glass cloth bedded down in epoxy resin. Advantages: Very sturdy and long-lasting. Disadvantages: More expensive and not removable, which make repairs more difficult.

3) Use one of the newer polyurethane systems, which eliminate the cloth and bedding. We have just completed phase I of our testing on a 100% solids polyurethane base coat that bonds VERY strongly to wood, fiberglass, steel and concrete. It's impressive stuff, slightly elastic and very tough. We have tested two topcoatings, which are also very impressive and bond strongly to the polyurethane basecoating: an acrylic/epoxy water-based blend available in grays, tans, a medium green and a brick red. It has spherical sand suspended in the emulsion and lays down very easily and looks quite classy. The other option is a aliphatic polyurethane topcoat, available in the same colors, but is a MUCH tougher final coating. Anti-skid material must be added. Advantages: Simple to apply, easily repaired if necessary, totally waterproof. Disadvantages: About the same expense as epoxy, and not easily removable.

We are going to re-do the decks on our old tug and use the polyurethane method.

That's the way I see it, given your particular situation. I haven't exactly answered your question, because I don't think mixing the covering processes is the best solution. Please feel free to come back with additional questions. We'll help you any way we can.