Abstract: A self-repairing and unsinkable watercraft has the hull of the mid section of the craft covered by two moveable water impermeable sheaths. The sheaths rotate in opposite directions to temporarily seal a breach and to allow for better ease of permanent repair or replacement. In one preferred embodiment, the craft is fitted on each side with at least one pontoon-like sealed foam structure that is attached by moveable telescoping arms. Adjustment of the positions of these structures with arm movement provides for greater stability of the craft during various maneuvers, aids in keeping the craft upright, and adjusts for changes in buoyancy and lift as needed. When additional stability is wanted, the craft contains a layer of sealed foam beneath the main deck at or above the waterline and from one to three submerged cylinders that are opened or closed to the water at both ends as needed.