Repairing an old Cedar-Strip Canoe

IMG_0586 My parents have several cedar-strip canoes. They all have keels, which do help tracking, but can cause stress to concentrate, and can lead to cracking of the canoe if it is handled roughly. One of my parents' canoes did crack at midships, just above the keel, as can be seen in one of the pictures below. This crack was patched, but the patch did not hold. As well, the varnish done after the previous repair was peeling and needed to be redone, as can be seen in one of the pictures below.

This particular canoe has a single rib, at midships. (See the picture detailing the inside of the hull, below.) The rib does stiffen the canoe, but it also concentrates stress, and was cracked. As well, the keel was just screwed to the hull, as can be seen in that picture, so that it did not strengthen the canoe. My plan was to remove the keel, patch the crack with epoxy, and then glue the keel to the hull. This would make the hull stronger, and hopefully prevent more cracking.

IMG_0593 IMG_0592 IMG_0591 IMG_0590 I first unscrewed the keel screws. Then I flipped the canoe over and unscrewed the rub strips from the keel. (These screws were not in good shape. Some of them broke and had to be drilled out.) I removed the final screws holding the ends of the keel to the hull. I then sanded the keel on my belt sander. The ends of the keel were quite delicate. They did not survive the sanding intact.

IMG_0602 IMG_0597 IMG_0596 IMG_0595 In preparation for gluing the keel back on the hull, I scraped and sanded it, using a variety of scrapers and sandpaper. The centerline under the keel was in bad shape, due to water getting in through small cracks and the screw holes. I had to carefully excise the broken fiberglass and otherwise clean up the centerline. The worst spot was, of course, midships where the crack was.

IMG_0613 IMG_0610 IMG_0604 IMG_0605 To reinforce the hull I decided to put an extra layer of glass on its bottom, cut to just cover the bottom. I used some 6-ounce glass that I had left over from previous projects. I make this glass in two halves so that the midships rib would have two layers. Before glassing I leveled off the centerline where I had removed broken and damaged glass by filling it with some epoxy. I then smoothed of the bottom of the hull, and laminated the glass to it. I finished by adding an extra strip of glass down the centerline.

IMG_0618 IMG_0615 IMG_0614 I glued the keel to the hull while the laminating epoxy was still curing. This gluing used the usual method of wetting the wood keel with unthickened epoxy and then using epoxy mixed with glass fibers as the glue. I screwed the keel to the hull, using the screws that used to be its only attachment, to hold the keel close to the hull while the epoxy cured. I had to fill in some gaps at the ends of the keel with epoxy and to glue the broken ends of the keel back to the keel and onto the hull. At the same time I also filled in and patched the crack on the inside of the hull with glass and epoxy.

IMG_1074 IMG_1073 IMG_1072 The next step was to prepare the outside of the hull for varnishing, but this had to wait for warmer weather, as varnishing is not a good idea in an unheated garage in winter. I did the rough sanding with my random orbital sander and the final sanding with wet sandpaper. Then I gave the outside of the hull two coats of varnish, sanding in between. I then screwed the rub strips back to the keel, flipped the canoe over, and sanded and varnished the gunwales. I also sanded and varnished the patch on the inside of the hull.

IMG_1079 IMG_1076 The result is certainly not as pretty as a new canoe, as this canoe has a lot of dings and scrapes, but it should be functional for quite some time.

Updated 14 September 2007 by Peter F. Patel-Schneider.