assault. He proposed a pykrete monitor long and wide mounting a single naval gun turret; this could be self-powered or towed to where it would be used. He also suggested the use of pykrete to make breakwaters and landing stages. At the time, Max Perutz thought the ideas were practical and that the preceding research on pykrete was sufficiently advanced to allow Pyke's plan to be executed. The plan was not put into action, but for the allied invasion of Normandy a system of preconstructed concrete breakwaters and landing stages called Mulberry was employed. Pyke's plans hint that he had some knowledge of the Mulberry plans, perhaps through his contacts with Bernal, who was one of Mulberry's progenitors. Men in pipes In late 1943, Pyke submitted to Mountbatten a memorandum, nearly fifty pages long, explaining his ideas for a solution to the problem of unloading stores from ships where no proper port facilities are available and few roads inland. This circumstance was common in the Pacific war theatre and fundamental to the 1943 decision to invade France by landing on the beaches of Normandy, with no harbours and a 24-foot tide. Pyke's idea was to use pipes of the type that were used to transport fuel from ship to shore, to move sealed containers that would contain any type of sufficiently small material objects. Pyke suggested that pipes would handle smaller equipment and larger objects could be passed through two-foot pipes. Furthermore, there was no reason why the pipes should stop at the shore, they could be extended inland as required. Bernal gave a cautious endorsement to the idea, adding that it would require a great deal of investigation. Pyke's idea was similar to the cleaning brushes that are sometimes forced along pipes by the pressure of the fluid and to the pipeline pigs which today are used for cleaning and telemetry. Pyke then proposed that his idea for "Power-Driven Rivers" could be extended to the transport of personnel. The pipes would need to be at least two feet in diameter and the pressures would have to be high. He worked out ideas for supplying the passengers with oxygen and suggested that the problem of claustrophobia might be alleviated by travelling in pairs and by the use of barbiturate drugs. Pyke proposed that this system could be used to move people from ship to shore, from island to island, through