A variable buoyancy system for deep ocean vehicles

A variable buoyancy system has been developed for underwater vehicles operating deep in the ocean. This paper reports on the design, testing and development of the system. The system was designed to change buoyancy at up to 1 l/min at a depth down to 6000m. The results showed that the system worked at its design specifications after modification but that friction losses resulted in a relatively low efficiency of around 35% at low working depth, but efficiency increased with increasing depth to about 70% at 6000m. Efficiency could be increased further with redesign or with changes in specification.