This entire area had to be trimmed of rotting wood, cleaned of oil and dirt, re-fiberglassed and a new sub-deck installed. The soaked wood compromised the fuel tank by corroding the metal over time. Metal type doesn’t matter, even stainless steel corrodes.
This tank was perfect in appearance from the inside. An inexperienced tank mechanic would think there was nothing wrong with this tank. In the end, there were seven pinholes rotting through the tank, nearly all invisible from the inside.
In the before photo, you will notice the unprotected and water soaked plywood had rotted away. The salt water trapped in the old wood is what helped create the corrosion on the bottom of the fuel tank. Gasoline leaks can cause life threatening situations in vessels. This situation isn’t solely a gasoline tank related issue, however, it is one of the most dangerous.
If you look closely, you will see small pock marks of corrosion, even through the black bacterial slime coating and residual diesel fuel of this tank interior. Notice the not so obvious corrosion indicators. The asphaltene coating is hiding some of it, however, the exterior of the tank is where the damage is in this stainless steel tank.
The black sludge on the sending unit float, is covered in asphaltene and bacteria. This tank was nearly empty of diesel fuel, but there was so much sludge in the bottom of the tank, the float was resting on top of 3” of crud and the gauge indicated ¼ tank of fuel. This condition can be prevented by use and the addition of diesel fuel treatments. Treatments are good, but cannot prevent the asphaltene fallout from the diesel fuel itself. Treatments can help break up the asphaltene and does prevent bacterial growth, however, unless the tank is empty or in use, asphaltene sludge build up will continue. The healthiest diesel fuel tanks are in use frequently.
Fuel Tanks Compromised
FUEL TANKS COMPROMISEDTHE MOST COMMON FAILURE<br />WHAT TO DO WHEN THEY FAIL<br />