Problem

SeaSoar is an oceanographic instrument vehicle that is towed at the end of a cable. It is a product of Chelsea Technologies Group, Surrey, UK. The towing cable contains a stranded outer structure for bearing the towing loads and one or more electrical conductors in the center of the cable. Electrical communication signals are used to operate mechanisms which control movable fins to cause the vehicle to "fly" upward or downward. This ability enables control of depth of the vehicle while it's towed so instruments in the vehicle can make their measurements in a range of depths. We worked as a part of a project group that integrated several instruments into a SeaSoar application.

Solution

Our work provided a power and communication system that supported several instruments carried on a SeaSoar. Power transmission in the cable was at about 250 VDC, and conversion to a variety of low-voltage application loads was performed in our assembly.

We created two circuit boards for this project. One contained power conversion and a cable communication interface. The other was a communication control processor board that operated power controls for several sensors and collected data from those devices for transmission up the cable.

We produced a pressure housing to contain the electronics and provide water tight connections to the power and communications cable. For the shipboard end we produced a rack mounted computer and power source to control the instruments and retrieve data.

Results

The system worked well in a number of cruises to measure distribution of plankton in the ocean.