The Coastal Ocean Institute and Rinehart Coastal Research Center's CTD Systems


The Coastal Ocean Institute has acquired two CTD systems which may be borrowed. These two systems increase the ability of the WHOI coastal community to make observations anywhere from the shelf break to shallow lagoons. The instruments are:

  • a smaller Ocean Sensors CTD for small boat deployment
  • a larger, fully instrumented FSI CTD for winch deployment
The Ocean Sensors CTD is small (6 cm diameter), can easily be carried in one hand and lowered over the side of an outboard skiff by hand (weighs 5 pounds in air). It is ideal for very shallow waters where larger systems requiring winches and conducting cable cannot easily be deployed. The system samples pressure, temperature and conductivity (it calculates salinity internally) and has additional inputs for other analog sensors such as a fluorometer, transmissometer or OBS. The CTD has an internal battery which will power it for several day's continuous use, or it can be powered down a cable which will also allow the data to be logged at the surface. The instrument communicates with the user through a standard 9600 baud RS232 channel, and can be used in a stored mode or real-time mode with a conducting cable. The storage capacity is adequate for making shallow water profiles. For additional information, contact Rocky Geyer (AOP&E).

The Falmouth Scientific CTD system meets NSF Level 1 CTD standards and is capable of being used on research vessels equipped with a winch. The system is composed of a basic FSI Integrated CTD unit with three temperature sensors (slow and fast platinum thermometers and a fast thermistor), conductivity and pressure sensors, a water sampler capable of carrying up to 12 standard 10 liter Niskin bottles. A Seatech fluorometer and transmissometer, and a LiCor PAR (photosynthetically active radiation) sensor are also available. The system has an altimeter which allows the distance from the CTD to the bottom to be read on the deck box in real-time, thus allowing the scientist to make close-to-bottom profiles with reduced danger of bottom contact. The instrument is modular and the basic CTD could be used by itself on a small boat with conducting wire to record temperature, conductivity and pressure profiles. The CTD also has a memory option (in place of the wire telemetry unit), powered by an external battery pack, and the data is recorded internally which may dumped to a PC later. The FSI CTD is calibrated and maintained by Marshall Swartz and the WHOI CTD group; to obtain more information and schedule its use, contact Jim Irish (PO).