Submetrix Sonar

This photograph shows Andy Howell and the Submetrix ISIS 300 sonar tow-fish, on board the M.V. "Terschelling" in Plymouth Sound.

The sonar fish is hanging by its tow-cable while Andy brings it aboard. The port transducer is visible as a black rectangle on the side of the fish. Inside are eight transputers, two sonar transmitters, a motion reference unit, interface electronics and a power supply, all contained within a pressure-resistant housing. At the other end of the tow-cable are more transputers, a B300 network interface unit, some ethernet and a Sun SparcStation 20.