Abstract: A self-elevating marine platform having a main hull whose length and width dimensions can be readily varied without thereby disturbing the main design of the platform. Added externally to the main hull are at least three auxiliary hulls which are separate and distinct from the main hull. The auxiliary hulls are welded to the port, starboard, and forward ends of the main hull. Each auxiliary hull contains a leg-elevating unit for receiving a leg therein whereby the unit, when energized, will cause the platform to move up or down on the legs which are arranged in a tripod. Each auxiliary hull forms a ballast or preload tank of sufficient volume to exert, when loaded with liquid, all the required mass on its leg.