One of the major projects that had to be completed over the winter was the replacement of the cabin sole. The plywood underneath the sole had become saturated and the whole floor was soft underneath weight. This was due to a post-factory modification (that was apparently common for Tanzers) which encouraged any moisture to wick into the cabin sole's plywood core. It is difficult to describe in words, so I've included pictures with notes that will hopefully explain what went wrong and the intended fix.
As this picture shows, the cabin sole is molded into the cabin liner. There are two rather large bilge access boards in the center of the sole which give access to all 10 keel bolts.
The sole relied on the whole liner for support, with the addition of 1/2" plywood glued to the underside of the floor. This material was known to become flexible around the bilge openings, so owners would add some kind of support. The supports were the problem, as they were installed in the lowest point of the bilge and they wicked moisture up into the plywood core, saturating everything under the fiberglass.
Click on the images below for more detail:
At first, I though that perhaps I could cut away only the supports and install new ones. The oscillating multi-tool worked great for this purpose, it reached into the tight space and was easy to control. Only after cutting some of the supports away was I able to feel the plywood underneath the sole and realize how wet it was. The whole sole was going to have to come up.
This hopefully gives a picture of the problem, showing how any water that entered the bilge ended up soaking into the plywood supports. It was impossible to remove any water that entered this area, all it could do was soak into the plywood. Obviously a dry bilge is the goal, but any moisture at all ended up right against bare plywood. For this reason, I gave up trying to rebuild the sole as it was and began thinking of other options.
This picture even better shows how the water ended up trapped in this area.
This picture shows how the supports were tabbed in with fiberglass. it is hard to see in the picture, but there were two areas of added glass, with a small area of original hull showing in between (the area in the green box). The red arrow shows the thickness of the added glass and that it didn't really adhere to the original hull glass that well (it chipped off with very little encouragement). Clearly the keel bolts were replaced after the extra glass was added. This is all assuming that it was a later addition and not from the Tanzer factory. I have been told that the boats did not come from the factory with these supports. Based on the differences in workmanship and materials, I would imagine this is true. It just doesn't seem to "fit" with anything else on the boat.
This photo also shows that I will need to tab in some support underneath the dinette floor, as that is currently unsupported (it is the area with the two-by-four stuck underneath—I couldn't remember not to step there).
So now what? That is the important question. I had considered replacing the core under the fiberglass skin and then refairing the glass where I had made the cut. This would, of course, require a different support system.
I then considered replacing the whole sole with something else, perhaps a teak and holly floor. Real teak and holly is too expensive, but I found a creative way of copying the teak and holly look.
How to support the floor though? I didn't want to put the supports in the same place, back in the deepest part of the bilge. The goal is too keep the bilge dry, but things happen and I don't want any wood down there when a hatch gets left open during a rainstorm or something like that.
I first considered tabbing in cross supports (running form port to starboard). These would be shaped so that water could run freely underneath them in the deeper areas. However, I didn't want to create any "hard spots" on the hull. Now, I am thinking about running supports fore and aft closer to the edges of the sole.
I then considered replacing the whole sole with something else, perhaps a teak and holly floor. Real teak and holly is too expensive, but I found a creative way of copying the teak and holly look.
How to support the floor though? I didn't want to put the supports in the same place, back in the deepest part of the bilge. The goal is too keep the bilge dry, but things happen and I don't want any wood down there when a hatch gets left open during a rainstorm or something like that.
I first considered tabbing in cross supports (running form port to starboard). These would be shaped so that water could run freely underneath them in the deeper areas. However, I didn't want to create any "hard spots" on the hull. Now, I am thinking about running supports fore and aft closer to the edges of the sole.
This is the inspiration for the sole replacement (click on the picture for a link with a full description of how the faux teak and holly look was created). Beyond that, the idea of supports that are attached to the sole itself (rather than glassed onto the hull) is attractive. These supports under the floor in the picture to the left probably rest on stringers, but the Tanzer hull doesn't need stringers. Thus why not just attach the supports to the bottom of the sole so that the entire thing can be removed and repaired if needed? It would also be handy for finding those split rings that find their way into the bilge area. The sole could be finished with quarter-round teak trim to cover up the seam (a flat piece of trim over the dinette area). If the trim is attached to the sole rather than the cabin liner, the whole thing would still easily lift up. For what it is worth, the sole dimensions in the Tanzer 22 are about 19.5" x 6'.
In order to prevent putting to much strain on the hull, it is important that these supports are wide enough to distribute the weight without creating any hard points. I am considering creating them out of a fiberglass lumber such as this form McMaster Carr. Alternatively, epoxied (or otherwise protected) wood lumber could be used. The only issue is determining how to shape these supports to match the curvature of the hull.