An improved discrete depth sampler for midwater nets

This report describes improvements in the electronics system controlling the four-chambered discrete depth sampler (DDS) on an Isaacs-Kidd Midwater Trawl. A resonant reed relay and voltage transfer relays are utilized to control the solenoids that close the doors of the DDS. The improved system is more reliable and allows greater flexibility than the original system. Notes on net speed and filtering efficiency are also given for depths to 2500 meters.