Fuel oil storage tank

Claim 1

A vessel of large size and integral molded construction comprising a cylindric wall having a longitudinal center axis, said vessel being horizontally disposed with respect to said center axis enclosing end walls disposed substantially perpendicularly to said axis at each extreme of said cylindric wall and adapted to define an enclosed space therewith, a depressed well positioned adjacent the forward extreme of the underside of said cylindric wall as a continuous integral appendage thereof communicating with the interior of said vessel and extending below said cylindric wall, an opening through the cylindric wall centered where a line passing through the center of said well and perpendicularly intersecting said longitudinal axis would intersect the opposing, upper portion of the cylindric wall, a first pedestal positioned at the underside of said vessel adjacent its rear extreme, said pedestal extending downwardly from the cylindric wall and terminating in a lowermost portion having the form of an elongated flat surface disposed in perpendicular relationship to said longitudinal axis, a second pedestal positioned at the underside of said vessel adjacent its forward extreme and extending downwardly from the cylindric wall to a lowermost portion located closer to said wall than the corresponding lowermost portion of said first pedestal and further from said wall than the lowermost portion of said well, said well being located between said first and second pedestals at a location closer to said second pedestal, said location defining sludge accumulation means such that the vessel, when rested on a horizontal flat surface, will be tilted downwardly toward said well at an angle within the range of 3 to 10 degrees measured between said longitudinal axis and a horizontal line causing sedimentary material to drain toward said well and accumulate therein, and the lowermost portion of said well will not contact said horizontal flat surface.