A survival craft comprises a hull (10) formed from inflatable members (12, 13) and mounting a powered propulsion system (18, 19) for the survival craft. A superstructure (11) is mounted on the hull and formed from inflatable members (25, 26, 29a-29i) and a flexible roof (28) supported by the inflatable members (25, 26, 29a-29i). The superstructure provides the hull (10) with increased longitudinal rigidity that reduces the tendency of the hull (10) to bow longitudinally when the propulsion system (18, 19) is operating. The survival craft forms part of a marine escape system with the survival craft deflated and packed in a container including an inflation system for the survival craft. The system has a deployment system for mounting on a marine structure and carrying the container with the deployment system transferring the container from the structure to the water where the inflation system inflates the survival craft for access by persons.