The Rot Doctor


Subject: caulking
Date: Tue, 03 Nov 1998

I own a 42' trawler, pine on oak built in'67 in Nova Scotia. 12'beam 4.5'draw 7kt cruise @ 1500 rpm great fun but will need re-caulking soon enough any suggestions/comments? She is at Big Bay Point, Lake Simcoe, Ontario Thanks


Oh boy! The caulking question....

There are basically two ways you can go: 1) The old way, with traditional cottons applied by a professional caulker (you can learn to do this yourself but you need someone who knows to show you how) and then with the seams final-fill with traditional oil-based seam compounds; 2) The "new" way with special synthetic seam prep compounds, some cotton, and final fill with a polysulfide or polyurethane compound.

Which is best? It all depends.... I personally suggest that if when your hull seams are reefed out and the planks seem good and true and free from rot or other wood decomposition, you stick to the traditional method. For a boat used locally in cold water and hauled annually this is the best -- and for sure the simplest. I suggest you ask around for the very best caulker and have him do the whole job for you -- from reefing to final fill. When he's finished, he'll be able to tell you a lot about your hull as well.

If you were telling me that you were going to take your boat to Florida and live aboard it in those tropical waters, then we might go over some of the advantages of the "synthetic" system. But for you, where you are, the old way is best -- in my opinion.

If you run into any significant amount of bad wood, then get back to us and we can talk about what you are seeing and what the simplest repair solution might be.