A compact CTD system with programmable controller for obtaining in situ water samples

A compact CTD system has been assembled consisting of a Seabird SBE-1 CTD, a General Oceanics rosette water sampler, and a programmable controller which allows bottles to be tripped at preselected depths. Controller gets depth from the CTD during the cast, compares them with preprogrammed values stored in memory, and then fires the rosette and stores several CTD data scans when the proper depths are reached. The system is compact and easy to handle, requires no electrical power from the ship, and all data are internally recorded in the CTD and controller. The system has been used successfully from small coastal patrol vessels in areas with strong currents where CTD casts must be performed rapidly. This paper describes the design of the controller and gives a preliminary evaluation of the performance of the system from data collected in the Caribbean