After our trip to the Chesapeake, we found that both forward
cabin mattresses were wet on the bottom inboard corners and that the storage
lockers under the bunks had collected a small puddle of water. It had not rained
in a while so it must be from the water system. The plumbing looked ok. The
forward lockers where the water tanks are located showed water at the aft end
of the tanks. Draining the tanks and removing them was the next step.
We found that the fiberglass module that supports the water tanks had not been completely fiberglassed into the hull at the
forward and aft ends. Any water that collected under the tanks drained into these holes. It
didn't look structural, so we filled the gaps with 5200 caulk. That took care
of the leaks into the cabins.
These tanks carry a big load. A full tank is almost 100
gallons at 8.3 lb per gallon, or about 800 lbs. We found that the tank support module
is two strips, with no support down the middle of the tank. We added a
narrow piece of plastic in the gap between the two existing strips to provide better
support to the tank bottom.
Next, we examined the tanks. Why is water leaking from them?
We had been told of a repair to the bottom of the port tank. The repair looked
ok, but seemed to be silicon caulk covered by a piece of duct tape. It came
right off. It was a long crack in the plastic tank - about 4-6 inches long. The
other tank developed its leak from a crack that was about 2 inches long,
located at the bottom of what I'll call "the donut hole" internal brace.
Plastic can be welded if the matching 'welding rod' material
is heated along with heating the tank itself so that they melt together. Mike did the research and found that the
tanks are made of low density polyethylene (LDPE) and that Rubbermaid makes several products from the same plastic. He found a
Rubbermaid trash can that has the letters "LDPE" in the recycle
symbol on the bottom. He cut a some strips from the trash can to use as welding
rods. We bought a plastic welder from Harbor Freight Tools. The first plastic
welder died while making the repair so we used a heat gun with the concentrator
adapter (a metal cone to concentrate the heat and air flow) to complete the weld of the first crack.
The easiest prep was to use a rotary tool (Dremel tool) with
a cutoff wheel, held diagonally, to grind open the crack in a nice U shape of
the desired width and depth. Then we used the heat gun/welder to heat the
plastic strip (welding rod) and the tank along the crack. We were careful to
not get the tank too hot and burn through it. We applied just enough heat to
get the plastic tank and the rod to turn glossy. As the rod melts, we swirled
it in a circular motion along the crack, to get it to bond with the tank
material. It is important to keep the welder far enough from the puddle that
the stream of air doesn't blow the material out of the crack. The result was a
very nice weld.
The plastic welding was a new and interesting experience
that saved us from having to buy new tanks at $400 each, plus shipping. We now
have dry bunks and our water stays in the tanks.
