Ballast tank arrangement for double-hull tanker

A ship comprising:

• a ship body having sidewalls and a bottom portion, said sidewalls having a top and a bottom, said bottoms of said sidewalls attached to said bottom portion;
• at least one cargo tank disposed within said ship body, said cargo tank arranged such that a first space is created between said cargo tank and said bottom portion of said ship body;
• at least two ballast tanks, arranged on opposite sides of said cargo tank between said cargo tank and said sidewalls of said ship body, said ballast tanks arranged such that a second space is created between said ballast tanks and said bottom portion of said ship body.

A vessel for floating on water comprising:

• a structure for floating on water and adapted for being loaded and unloaded;
• and
• at least two ballast tanks adapted for containing ballast water when the vessel is not carrying a full load, said ballast tanks being mounted on said structure at a height such that the ballast water may be drained by gravity.

A vessel for floating on water while either carrying a full load or not carrying a full load, comprising:

• a structure for floating on water and adapted for being loaded and unloaded;
• and
• at least two ballast tanks adapted for containing ballast water when the vessel is not carrying a full load, said ballast tanks being mounted on said structure such that the ballast water is contained at an elevation above the water line of the vessel.