Patent ID: 7178474

Claim:
An apparatus for maintaining a fluid ballast in the hull of a boat comprising: a container within the hull for holding seawater ballast, a plurality of flexible bags mounted in said container so that the volume of said plurality of flexible bags displaces a like volume of seawater ballast from said container so as to maintain a substantially constant volume of fluid ballast in said container, wherein said ballast bags are adapted for holding useful fluids including potable water in a first ballast bag of said plurality of flexible bags, motor fuel in a second ballast bag of said plurality of flexible bags and re-captured grey water in a third ballast bag of said plurality of flexible bags, pumping means for extracting said useful fluids from said first and second ballast bags for use in the boat, and return means for returning re-captured grey water re-captured from use in the boat to corresponding said third ballast bag, where said ballast bags are in fluid communication with said pumping means within the hull for extracting said useful fluids from corresponding said ballast bags and said return means for returning re-captured grey water to said corresponding said third ballast bag, a means for displacing said like volume of sea water from said container so as to displace seawater from said seawater ballast to compensate for increasing volume of said grey water in said third ballast bag, and means for filling said container with said seawater ballast to compensate for said extracting of said useful fluids, thereby providing a substantially constant volume of fluid ballast including said seawater, said useful fluids and said re-captured waste fluids.