Restoring the cockpit sole on a Cape Dory Typhoon, Part One
While removing most of the cockpit fittings on Cantaora, I noticed the cockpit sole was so soft that it felt dangerous to step on, making it a priority item to fix contrary to my general plan to avoid fixing anything that can be addressed later when the boat is in the water (fixing up an old boat is not an easily pre-planned, linear process.)
My boat came with 12" long teak tiles covering the sole, stuck on with generations of caulking in an ultimately failed attempt to block leaks. It covered-up a lot of issues and had to go. Generally IMHO teak decking is excess weight, and too hot under bare feet in the tropics anyway, so I had no plans to salvage or replace it.
Thankfully there was no 3M 5200 used and the teak came off the cockpit sole easily with a pry-bar. In some places even the bottom fiberglass layer was compromised. The oval wood cover piece around the rudder shaft popped right off after I removed the tiller head (and discovered an issue with the bolt that was supposed to secure the tiller head to the rudder post, details to come later.) I noted the area around the rudder post has no core and only a single layer of fiberglass.
I was surprised that there had been no attempt by the maker to glass-over the slot in the cockpit sole that had been cut there to allow the deck to slide over the angled rudder post during construction and attachment of the deck to the hull, relying only on the seal created by an oval wooden cover piece to keep water in the cockpit from leaking below. I will glass over the slot all the way around and up the rudder shaft.
The cockpit sole consists of the usual two layers of fiberglass with balsa core sandwich construction. A few investigatory holes drilled in the cockpit sole showed at least a third of the entire sole had suffered moisture damage to the balsa wood core. The plan was to remove all the balsa in the sole, and replace it with foam core, adding a a bit of camber and also a gutter around the sole to promote drainage.
Removing the core chunks at a time was the best approach. Using an angle grinder with a cut-off wheel, I carefully cut roughly 2" rectangular patterns through the top layer of fiberglass and remaining balsa core, taking care to avoid cutting through the bottom layer of fiberglass. The bottom layer serves as a base to build up the new sole, so keeping it intact helps. My biggest concern was actually to avoid the edges of the cockpit sole where typically the balsa core ends leaving only one layer of fiberglass that would be too easy to inadvertently cut through all the way. A few investigatory drill holes showed that the balsa core ended about an inch from the edges, so I made a point of only cutting within 1.5 inches of the edges of the cockpit sole. (Later,when laying glass over the bottom the sole, the left-over balsa core around the edges was scraped out with a chisel, and the gap was filled with strengthened epoxy filler.)
The area around the scupper drains was the worst, and the entire sole was basically disintegrating there. It was also covered with gobs of caulkling and filler so I decided that the easiest way to remove the scupper drains was to simply cut them out of the sole with a hole saw, and remove the whole scupper assembly including the hose as all of this will be replaced anyway. This left two holes that were filled and later glassed over along wit the rest of the sole. Two new scupper drain holes will be drilled later.
Once the rectangular patterns had been cut all over the top layer of fiberglass and balsa core (a cutting depth of about 3/8") while avoiding cutting all the way through the sole, I used a hammer to whack a wide-edged chisel to basically pop-off the fiberglass and balsa core in rectangular chunks. The places where the wood core was rotted were easy to remove as the wood could be simply scraped away; some leverage was required to pop off the pieces of still-dry balsa core. The entire cockpit sole all came off in chunks easily enough in one afternoon, leaving the lower layer of fiberglass mostly intact.
Next after filling in the sole edges with filler, and giving everything a light sanding to remove the last pieces of stuck-on balsa core, I placed two layers of 1708 fiberglass matting athwartship from edge to edge of the cockpit sole in 8" wide strips, overlapping the strips about a couple of inches, thus further strengthening the bottom fiberglass layer of the cockpit sole and covering all the holes in it.
While the fiberglass on the cockpit sole was curing, I started making the cockpit sole gutters using 1" PVC pipe as a mold, covered with clear plastic tape to prevents the epoxy from sticking to the pipe. I draping two layers of light fiberglass matting over the length of the pipe. After the fiberglass cured, I removed the PVC pipe mold out of the fiberglass and trimmed the edges off to get long half-round shaped fiberglass gutter molding. These were then cut into sections matching the lengths of the four sides of the cockpit sole and stuck-on to the sole edges with epoxy filler. For now this formscthe basis of the drainage gutters aroundvthe sole, to be further shaped and detailed later.
I had planned on using flat sheets of Divinycell to cover the sole at this stage but the bottom layer of the fiberglass sole was far to uneven and would have required a lot of work to flatten out first, and I didn't want any gaps under the foam so instead I decided to use pour-in floatation foam which is sort of self-leveling while still in liquid form.
Mixing several small batches at a time, I poured the liquid foam mixture until it fully covered the cockpit sole. The foam expanded a bit more than I expected in a few spots and spilled into the gutter I had built around the cockpit sole, but it scaped off easily with a chisel before it was fully cured. Since the boat was not positioned perfectly level on her trailer, the foam also tended to accumulate in one particular corner of the cockpit sole but I minimized the overflow there by pouring the batches of foam mixure farther way from that corner.
Once the floam had cured, it was not exactly flat and level. I started sanding it all flat. Once cured, the foam is suprisingly hard so after trying a palm sander, I resorted to a wire brush cup on my angle grinder to do the heavy material removal, then switched to a drum sander and also a low-grit flap disc on my angle grinder to do the detail work. There was of course a lot of dust, but once the foam on the cockpit sole had been sanded flat and even, I covered it all with a layer of epoxy filler.
The cockpit sole is now watertight and safe to walk upon.
Part 2 will involve placing the top layer of fiberglass on the cockpit sole, and some detail work around the drain holes for the new scuppers and rudder shaft. There will be a lot of sanding and fairing of the gutter around the cockpit sole too, leaving the application of paint and non-skid to the sole for later blog entries.