With a view to developing and strengthening indigenous capabilities in marine instrumentation and systems relevant for generating critical information and for supporting exploration and resource harvesting activities, development work on fish finders for various ranges, communication and navigational equipment and few marine general equipment were taken up. As recommended by the Inter Departmental Steering Group on Ocean Instruments and Systems the work on design and development of various fish finders both for vertical and horizontal scanning were sponsored through the Department of Electronics and taken up at the Electronics Research and Development Centre, Thiruvananthapuram. Fish finders are expected to be available for field trials by September 1992. Further work on design and development of radio direction sensors, underwater sonar, ocean acoustic remote sensing, etc. were also initiated.

6.1 Vessel to Shore Communication System

At present traditional craft and medium size fishing vessels operating in the coastal waters of the country are exposed to high risks and have no means of communication with the shore. Realising the need for such a communication system, the Department has taken up a project to develop 1000 sets of communication equipment which will be given to fishermen on a pilot basis in the States of Andhra Pradesh, Karnataka, Tamil Nadu, Kerala and Gujarat. The project work to produce 1000 sets of communication equipment and to install 9 shore transmitting stations with VHF radio telephone has been entrusted to the Marine and Communication Electronics (India) Ltd. Visakhapatnam. The first batch of 50 walkie talkie sets are expected to be available by June 1992. This is a unique project for the benefit of fishing community. The communication equipment together with the information about the potential fishing zones provided under MARSIS programme would enable fishermen to not only enhance the fish catch capability, but also provide a warning system against the impending dangers of any cyclonic storms while at sea.

6.2 Design of Submersibles

Feasibility study concerning the design and development of a submersible capable of diving down to a depth of 600 metres for exploration in the first phase and 2500 metres in the second phase and conversion and remodelling of the mother ship for the submersible was initiated. The study is expected to be completed during next year. Design and development of the following instrument was completed during the year .

6.3 Design and Development of a Free- Fall Bathythermograph

An instrument designed, developed under this programme was field tested during the ORV Sagar Kanya cruise 70, from 26 November to 31 December 1991. The instrument collected and stored depth and temperature data at one metre intervals upto 1000 metres. The instrument was also operated along with the on board Sea-Bird CTD system.

6.4 Development of Moored Ocean Data Buoys

Atmospheric forcing is an important factor in the study of oceanic circulation since it influences currents, surface waves and exchange at the air-sea interface. A typical air-sea interaction experiment requires measurements to be made of variables in the atmospheric surface layer, mixed layer of the ocean and the interface in between. Sampling rates of several times per second required for some variables are chosen to provide accurate mean values.

To provide a platform for the above studies, a data acquisition system has been designed. Ten minute sampling and hourly transmission of data is accomplished for near real-time viewing and analysis. The package consists of the following, sensors for measuring wind speed, wind direction, air temperature, sea surface temperature, buoy temperature, baro pressure and buoy heading, in addition to standard system monitors such as battery voltage, references and real time stamp.

One data buoy was moored off Cabo, Goa on 26 March 1991 and data collected for six days before its moorings were snapped. This buoy and data were recovered and two buoys are expected to be deployed before April 1992.

The back up Work of maintaining the instruments in Sagar Kanya and Sagar Sampada by one of the Indian electronic companies was also initiated.