Abstract: A marine vessel is defined by multiple modular floatation modules, each of which is defined by a float captured in a frame. Plural floatation modules may be interconnected in a variety of configurations to vary the size and shape of the vessel. A deck is supported on the floatation modules and superstructures may be supported on the deck. The vessel is operable in a first on water mode in which the beam of the vessel is a first width, and in a second on land mode in which the beam is a second width that is narrower than the first width and preferably within the width allowable for towing on roadways. Wheels may be incorporated on the vessel in either the first or second modes or the vessel may be loaded onto a trailer. In one embodiment the vessel has wheels attached to the hull (either permanently or removably) and a trailer hitch assembly is located at the stern of the vessel so the vessel is towed stern-first when towed on land.