I'm going with aluminum
because I'm concered with what additives might be added (in the future) to deisel and what additives are being added to bio deisel now.
I replaced the aft water
tank because it has been in contact with bilge water
for twenty five years just like the fuel tank
. The large, main water tank has not been in contact with the bilge
water, appeared to be in good shape, and did not need to be moved to replace the other two tanks
so I left it alone.
I did increase the size of the old 75 gallon fuel
tank to 110 galllons by adding 20 inches to the front of the tank. This part of the tank extends to the area previously occupied by the aft water tank. The new aft water tank (35 gallons) no longer has the bottom section and now looks more like a saddle tank located over the front of the new fuel
tank. Both have fittings that would allow the new aft water tank to be easily converted into an auxillary fuel tank if ever needed (the auxillary fuel tank would gravity feed into the main fuel tank).
The new tanks were build for me by Ezell Industries in Perry FL and I highly reccomend them. Ezell Industries Custom Aluminum Marine Fuel Water Holding Tanks Fabrication
Again, If I can be of any help feel free to email