MACHINE BUOYANCY CONTROL SYSTEM

摘要

A buoyancy control system for a machine (10) which is submerged during normal operation, the system comprising an attachment (25) for releasably attaching the machine (10) to a fixed structure (24) below the surface of a body of water in use. The machine is provided with a rigid vessel (30) is arranged to maintain gas under pressure and a further vessel (32) of variable internal volume. A valve arrangement (38, 40) controls fluid communication between the rigid vessel (30) and the further vessel (32), the valve arrangement being selectively operable at a depth below the surface of the water to allow fluid communication between the rigid and the further vessel such that the volume of the further vessel is variable under the action of the surrounding water pressure.