Abstract: A mast supporting structure for an inflatable dinghy including a pair of stringers for connection to the floor of the dinghy, a mast receiving tube adapted to receive the lower end of a mast, a transverse support member resting on the floor of the dinghy and which supports the lower end of the mast receiving tube, and a plurality of struts. The transverse support member is connected to one of the stringers at each of its ends and each strut being connected at one end to the mast supporting tube and at the other end to one of the stringers. The mast supporting structure may be connected together in articulated fashion so that it may be collapsed into a neat package in which all the parts lie alongside one another for transport and storage. When erected the mast supporting structure is connected to the floor of an inflatable dinghy and provides a rigid support for a sail carrying mast.