Abstract: A trimaran has a central hull, a pair of floats and outriggers for supporting the floats on each side of the central hull, and inboard supports from which the floats can be suspended in an inboard position. The outriggers are pivotally mounted, about substantially vertical axes, on the central hull, so that the floats can be moved bodily along track surfaces defined by the outriggers until the floats are supported from the inboard supports. The outriggers can then be pivoted so that they are positioned alongside the central hull. The arrangement allows easy overland transportation of the trimaran on a trailer.