I got to return to Robin this week, from Monday through yesterday noon. The project at hand was repair of the rotting aft bulkhead in the V-berth. There were some ups and some downs.
Climb up on the V-berth platform, do some work in a pretzeled position in the cramped quarters under the deck, realize I needed one more tool than I had brought and, unbending, climb down to fetch it.
This process was repeated -- for more tools, to make measurements, to see what things looked like on the opposite side of the bulkhead -- for most of two days. My lower back complained bitterly.
At one point on Tuesday, I thought I could make the repair without removing the waste holding tank from under the V-berth. The bulkhead is made of 3/4 inch plywood, and the less of it I had to remove, the better.
Early on I'd discovered the source of the rot. I'd thought that water had come in through a leak at the bow, traveled on top of the 1/4 inch plywood headliner until it reached the bulkhead where it was stopped, and there did its dirty work.
But I hadn't yet removed the final piece of headliner -- the one that butted against the bulkhead.
When I removed that last headliner section, I saw how wrong my diagnosis had been. To understand, you need to know the whole construction of the holding tank.
The tank is a rotomolded polyethylene box. It has three openings -- one where the waste enters the box, another where it drains from the box and a third small hole for a vent, so that a vaccuum doesn't collapse the box.
The tank is plumbed with a line coming from the head and entering one fitting and another 1 1/2 inch line exiting the box. That line leads to a T fitting. One line leaves the T and goes through a valve to the seacock which, if open, allows the waste to dump overboard. Another line leaves the T and goes up to a pump-out fitting on the deck. When the valve below is closed, the waste cannot dump overboard and occasionally has to be pumped out through the deck fitting.
The deck fitting was the source of the rot. More accurately, it was part of the route that water landing on the deck took to get to the bulkhead.
Robin has a teak deck. The teak is old and worn, and the caulking between the teak planks is shot. It is almost impossible to keep caulk between the teak planks because the wear is so extensive.
The result is that water had run into the spaces where the caulk was missing and followed along until it reached the pump-out fitting. Then it just dropped down through the hole bored in the deck and landed on the top edge of the bulkhead.
So the first thing I did was remove the pump-out fitting from the deck, clean out all the old caulk between the planks surrounding the fitting, recaulk those seams as best as I could, recaulk the fitting and return it to its place.
Once that job was done, I spent a lot of time probing the bulkhead. A sober assessment revealed that to get at all the rot, I had to remove the holding tank.
The short story of the arduous labor is that the tank is out and I have made a pattern of the wood that must be replaced. Today I'll buy a piece of 3/4 inch plywood large enough for the job and shape it according to the pattern.
In two weeks, when I return to Robin, I'll have to go slowly to make sure my repair is strong so that I won't have to repeat the project in the near future.
What this week's work has convinced me is that I can expect only more such problems until I've removed the teak decking, covered the underlying fiberglass with a new layer of glass and effectively sealed out the water.