Performance data of a buoyancy driven deep sea YOYO-profiler for long term moored deployment

Within the framework of the national funded project DOMEST a deep sea YOYO profiler is to be developed at the University of Bremen, MARUM (Germany). The goal of this system is to take continuous CTD-measurements over a depth range of 500 m above the ocean bottom. The system is designed to withstand a maximum pressure of 400 bar and is supposed to take one profile each day within one year. The system is also well suited to accommodate additional sensors as for example current meters or fluorometers. The basic instrument carrier contains a hydraulic propulsion unit similar to the well known ALACE floats. The hydraulic system is built to produce a buoyancy change of up to 3 kg to enable free profiling motion along a taut mooring line. The electronic unit contains a new PC-based microcontroller that is expected to have a superior performance compared to the well known TATTLETALE systems. The development of a deep sea version calls for a special design of the whole instrument of smallest achievable volume. Therefore the applicability of now pressure housing materials as for example ceramics is going to be tested