Water borne vessel for use at sea and on lakes

摘要

The fins (12) support the hull (10) when extended from it, and retract at least partly for underwater working. A propulsion mechanism (52), which may be retractible, is provided for use in both conditions.The fins can be set in a partly retracted intermediate position also for surface work, and where separate propulsion mechanism are provided for surface and underwater work, the first of these can be arranged to retract into the hull.