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.