Changing out the fuel tanks on Talisman

Why haven't we been cruising lately? The most obvious answer is that it's so infernally hot and muggy along the Gulf Coast. Besides it's storm/hurricane season, and today's the anniversary of the last horrific storm to hit New Orleans. Hurricane Katrina.

We might have tried to sail at night or make small trips in and around Pontchartrain Lake, but as it turns out, we found we would have to change out the fuel tanks. Mike has done a superb job of adding life to our handsome, aging gracefully sailboat. (Might that refer to us too? Surely hope so.) I, for one, am looking forward to our next sailing adventure.

Here's Mike's account of the tank replacement project:

PART I

Removal of the Old Steel Fuel Tank

I recently removed the 50 gallon steel fuel tank from Talisman, my wife’s and my 1979 Pearson 365 sailboat, in preparation for the installation of two new replacement tanks. As this is a task that is faced sooner or later by many boat owners, a description of the process is provided here for the adventurous do-it-yourselfers. Of course, one might wonder why one would ever need to replace a fuel tank. The answer is that all metal fuel tanks are subject to corrosion and eventually start leaking. Many start to leak after only a few years while others last a lot longer. Also, they all eventually accumulate lots of crud in the bottom of the tank that is often hard to remove and may clog the fuel filter (and prevent the engine from working) when it gets stirred up in choppy water.

One alternative I considered was to pull the engine and remove the old tank through the passageway. Then it could be replaced by a single tank of equal size, installed through the passageway. After receiving a cost estimate for this approach, I decided on a different approach. I cut the existing tank in half, removed the pieces through the cockpit lockers, and replaced it with two tanks, each half as wide as the original. The smaller tanks were installed through the cockpit locker, thus saving the cost of engine removal. Actually, it is not as big a job as I had feared. The removal of the old tank can be completed by a single person in a single day if you are well organized.

The first job was to remove as much fuel from the tank as possible. I disconnected the fuel hose where it attaches to the primary fuel filter and used an electric fuel pump to transfer the fuel into five gallon fuel cans. It is best if the tank is less than half full before beginning.

When I emptied as much fuel as I could, I poured in a gallon of degreaser and a gallon of water. I know that diesel is less easy to ignite than gasoline, but I didn’t want any unpleasant surprises. I then siphoned out a small amount of the mixture and tried to ignite it with a BernzOmatic torch. It failed to ignite, so I began cutting.

My old tank had a single baffle running perpendicular to the centerline. This seems to be common for tanks of similar size. The first step was to cut out two rectangular sections on each side of the tank, one before the baffle and the other after. I cut these sections as large as possible to afford maximum access to the inside of the tank. I used a reciprocating saw with a heavy duty bimetal blade with 14 teeth per inch. The tank was made of 0.125 mill steel, but cutting went quite fast. Once the sides are opened up, the remaining fuel mixture can be removed with a plastic scoop or a cup and a few wads of paper towel.

The next step was to cut the baffle in half. Using the openings already cut in the sides of the tank, I cut to the center of the baffle from each side. Due to obstructions and cramped space in my boat, the front and back walls of the tank were most easily cut with the saw inside the tank. Again, I started from each side and cut to the center.

Once the tank is cut in half horizontally, the top half was removed through the port cockpit locker. The bottom half was a little trickier for one person to get out, but it can be done. After removing the tank, be sure to vacuum up all the small metal pieces so they don’t leave rust spots.

Why did I do all this? The old tank was 30 years old. Although it wasn’t leaking, I assumed that it was living on borrowed time and I didn’t want to worry about it starting to leak in the middle of a cruise. However, when I removed the tank and inspected it, I didn’t find any part that looked to be on the verge of failure. It was, however, extremely dirty inside. Would I undertake this project if I knew then what I know now? I think so, even though the tank didn’t appear to be on the verge of leaking. In any case, I am looking forward to completely clean new tanks and the added flexibility that a two-tank system affords.