Instrumentation for a low drag hydrodynamic test vehicle

One of the major problems in designing practically useful autonomous underwater vehicles (AUVs) is achieving a useful combination of range and diving depth. It has long been known that in principle the hydrodynamic drag on the vehicle can be drastically reduced by optimising its shape, but there has always been doubt as to whether this approach will work in real sea water. One means of testing the concept in the open sea is by the use of a buoyancy-propelled vehicle making a vertical ascent from a suitable starting depth. The paper describes the design and instrumentation of such a vehicle. The instrumentation is based on an acoustic telemetry system and a microcontroller-based data logger storing data in battery-backed RAM. Some at-sea results are discussed