fresh water tanks
Fresh water tanks are built into the hull. As a result, the hull serves as bottom and outside walls for each tank. Three tanks in the bow can hold 15,338 gallons of fresh water, three tanks in the stern have the capacity for 6,560 gallons. A Day Tank in the hold can carry an additional 1,630 gallons of fresh water.
Fir was mothballed with her water tanks filled. Since the water was undisturbed for many years, there was little oxygen content, and not much evidence of rust inside the tanks. Unfortunately, water from the stuffing box sprayed exterior walls of the aft water tanks resulting in small holes. Joe cut plates of 7/16ths steel, considerably larger than the hole, and welded the plates to the interior of the tank. We weld to the interior to, among other reasons, avoid starting an oil fire in shaft alley. Since this repair doesn't solve the problem, we will need to provide a drainage system for the stuffing boxes.
Over the years, minerals in solution coated the tank interiors with rust and sediment. We used CLR and a pressure washer initially. Although not enough to completely clean all areas, the first pass did reveal surface rust in spots. Fortunately, nothing was larger then the size of a quarter. We used phosphoric acid, then muriatic acid to effectively dissolve light rust without damaging clean metal.
There are a few challenges to painting the tank interiors. To begin with, paints designed for water submersion require several very thick applications. In addition, interior baffles and rivet construction create a lot of intricate space. This task is not only time consuming, but labor is done inside the tank where there is little ventilation. To ensure the safety of those working in the tanks we will need air filtration masks and exhaust fans. Check back to see how we addressed these challenges.