(repair, text and photographs by Chris Cleary)
This website last year carried a notice regarding a second-hand Australian Sailfish for sale in an antique store in Geelong. It was a boat from the early 1970’s, the provenance of which, unfortunately, remains a mystery.
It was inspected in late November, and found to have quite a handsome varnished deck.
When turned over however, ugly holes were revealed in both port and starboard bottom panels in the forward section of the hull.
Despite this damage, the boat was rescued for liberation into the Sailfish paradise on Lake Macquarie in NSW.
The technique to repair this sort of damage is relatively straight-forward. In a painted boat it is easy to get a good aesthetic result. This is less readily achieved on a varnished hull, even with careful matching of the grain of the plywood patches. In a varnished boat, damage such as this has often been the trigger for a change to a painted finish.
The first step was to trim the holes to a regular shape. Be careful to check with fingers the extent of damage on the internal surface of the bottom panels, and expand the hole as necessary so that all damage is removed.
When the holes were adequately trimmed, tracings were made.
These tracings were transferred to a couple of pieces of off-cuts of 4 mm ply that were already pre-coated with a few coats of unthickened epoxy. It is critical that these patches be exactly the same thickness as the panels being repaired, otherwise you will have an uneven finish.
A backing frame for both holes was then made from the same pre-coated 4 mm ply. On the port side the frame was made in two pieces to enable it to be more easily fitted into place. The backing frames were glued with thickened epoxy to the inner surface of the bottom ply, the frames overlapping the perimeter of the holes by about 10 mm. They were clamped in place while the epoxy cured overnight. These frames also protruded into the holes by about 10 mm or so, providing a glueing surface for the patches. They act as butt straps or pads for what are essentially butt joints between the patches and the bottom panels. On the starboard side, a partially exposed stringer acted as part of the backing frame for the patch.
The patches were dry -fitted to the holes. Note that it is not necessary to have a tight fit. A slight gap provides a space into which sanding filler can be squeezed at a later stage in the repair. This seems to lessen the likelihood of the rectangular patches being discernible through the finished paint job.
The patches were glued into place, covered with pieces of plastic and held in place with gravitational clamps (also known as bricks). The patches and surrounding ply were sanded back after the epoxy had cured.
To allow for final fairing, a generous coat of sanding filler was applied with a squeegee to the patches. I use Bote-cote epoxy, which was thickened with Bote-cote sanding filler powder.
It provides a readily sanded surface which can be faired with higher and higher grade sandpaper to a perfect finish. Some areas of the filler coat will become almost translucent with sanding to a fair surface.
The repair at this point is ready for painting by the boat’s new owner at Toronto on Lake Macquarie.