Abstract: A floating platform is assembled from a number of square or rectangular modules. In the corner edges of the modules are slots adapted to receive link plates. Keys lock the plates to the modules by passing through bores in the modules and holes in the plates. The holes in the plates are shaped so that rotation of a key within a hole towards a locking position cams the plate further into its slot. Recesses are provided in walls of the modules to prevent water from spurting onto the surface of the platform when the modules are brought into abutment. Apparatus is provided around the edge of the platform for attaching posts and hinged ramps.