National Institute of Ocean Technology at Chennai established by DOD as its technical arm has completed 6 years of technology development activities. NIOT’s activities are in the areas of Ocean Energy, Deep sea mining, Coastal and Environmental Engineering and Marine Instrumentation. Two pioneering projects are in the area of mining technology demonstration and design and installation of 1 MW floating OTEC pilot plant. A new activity, which has been added to NIOT is the provision of science and technology inputs for the Island communities. Other operational programmes handled by NIOT are National Data Buoy Programme (NDBP) and Operation and Management of Coastal Research Vessels owned by DOD and AA Sidorenko.

Mission - I : Ocean Energy

Ocean Thermal Energy Conversion (OTEC)

The major programme of the group is the Design, Installation, Commissioning and Demonstration of the 1 MW (Gross) floating OTEC plant. This 1 MW floating OTEC plant working on the closed cycle principle with ammonia as the working fluid will be installed on a barge that is moored in a manner such that the 1m High Density Poly Ethylene (HDPE) pipe forms a part of the mooring, The detailed design of the power module has been completed. It consists of four numbers of titanium evaporator and four numbers of titanium condensers, a four stage axial turbine and pumps for operation of ammonia, cold and warm sea water circuits.

The titanium plate heat exchangers are the largest of its kind in the world. The Turbine is being manufactured indigenously and the design has been reviewed by an Expert Committee constituted by NIOT. The cold water pipe, which is of 1 m diameter and is made of HDPE will be towed horizontally to the OTEC site and upended for connection to the barge. In order to understand the issues associated with the power module of the OTEC plant, especially under off design conditions NIOT has also constructed a 1 kW demonstration OTEC plant, which consists of a warm water source, chiller, which serves as the cold water source and also has plate heat exchangers for evaporator and condenser.

Wave Energy

The work on the fixed guide vane impulse turbine at the National Test Facility at Vizhinjam was completed. The hydrodynamic efficiency of the Backward Bent Ducted Buoy (BBDB) was measured in the wave energy basin at IIT Chennai.

MISSION II : Deep Sea Technology and Ocean Mining

Development of technology for deep sea mining of polymetallic nodules is one of the main activities of this mission. The progress under this mission is reported under the Polymetallic Nodules Programme of the Department.

Under this mission an underwater thruster is being developed for operation at 1000 metre depth. The project involves multi-institutional participation by PSG College of Technology and CMERI, Durgapur. The thruster will be manufactured and testing will be taken up shortly. In addition, prototypes of underwater electrical connectors have been designed and manufactured for 1000 metre operation and are being tested by NIOT.

A novel jet pump with a non-axisymetric suction has been developed suitable for handling large solid particles. The pump has been tested in an experimental set up (50 mm diameter pipeline) at IIT Chennai for four jet nozzles (8.8 mm – 17.5 mm diameter) using gravel (3mm-10 mm size) for a maximum delivered concentration of 25% by weight. In the next phase the pump will be tested in a pilot plant that is being developed (200 mm diameter pipeline and 125 tonnes per hour capacity) using gravel (maximum size : 30mm). Efforts to patent this novel design are in progress.

MISSION III : Coastal and Environmental Engineering

The major activities under this mission in the current year are in house modelling of coastal inundation due to storm surges and industry oriented consultancy services for coastal projects. Available numerical models for various coastal processes like MIKE- 21 and MIKE-3 are applied to Indian coastal environment conditions for providing typical solutions to industry.

Forecasting Models for Coastal Natural Disasters

NIOT has developed a finite element surge simulation model and it has been benchmarked with MIKE-21. The model has been calibrated with data on previous cyclones. Estimation of inundation is interpolated into the finite element model. This model is being applied to estimate inundation of Andhra coast during cyclone crossing.

Further, NIOT in collaboration with international consultants like Babtie International and Delft Hydraulics has undertaken a technical study towards Andhra Pradesh Hazard Mitigation and Emergency Cyclone Recovery project. The main objective of the project is to achieve sustained and effective wind, rainfall & storm surge forecasting for the AP Coastal region so as to reduce the loss of property. Experts of NIOT prepared a report on the existing surge simulation models in India and this formed the basis for evaluation of the existing models. Under this project, the mission also involves watershed and delta management including flood modelling in the cyclone prone areas.

Waste Load Allocation (WLA) & Environmental Impact Assessment (EIA)

The two projects executed by NIOT under the ICMAM project, WLA & EIA are proceeding on schedule and have been reviewed by World Bank during the Mid Term Review. The WLA project for Ennore has completed the three monitoring surveys and field experiments. Modeling has been initiated. The EIA guideline for Ports & Harbours has been reviewed by national experts and the preparation of final guidelines is under progress. These final guidelines will be distributed by DOD / MOEF.

Under the physical oceanographic component of COMAPS the first phase of sampling at Paradip, Visakhapatnam, Mangalore has been completed with the cooperation of NIO (Vizag & Kochi) and RRL Bhubaneswar. The second and third phases are due for completion by October 2000.

Consultancy Services for Development of Marine Facilities

NIOT has completed the Seabed Engineering and Oceanographic surveys off Pettodai-Periyakuppam area near Cuddalore for development of Single Point Mooring off Cuddalore and Gopalpur. These investigations include collection and analysis of bathymetric data, sea bed morphology, sub seabed geology and shallow sampling of project area. Current and wave measurements were also made during monsoon periods.

Geophysical and geotechnical surveys which were taken up by NIOT for the Pipavav Gas Pipeline Project across the Gulf of Khambat, awarded to NIOT by M/S British Gas Private Limited during November, 1999 were completed in a record time of just over 2 1/2 months. This work includes bathymetric survey using Swathe and Echosounder, Side-scan sonar survey, geophysical survey, magnetometer survey and interpretation of geotechnical and geophysical parameters within the proposed pipeline corridors. This project also includes landfall survey consisting topographical survey, geophysical survey, soil resistance survey, geotechnical survey, onshore position control and seismic study. Geotechnical survey included grab sampling, vibro coring, rock coring and cone penetrometer, in-situ measurement, etc.

National Thermal Power Corporation has requested NIOT to study and recommend appropriate and cost effective coal transport logistics for their proposed 1000 MW power plant at Cheyyur, South of Madras. Oceanographic studies for development of marine facilities at Cheyyur to handle the required coal transport have been carried out. This study includes estimation of coal transport per ton basis for various options like offshore open jetty facility, shore based marine facilities and the required infrastructure like trestle and material handling equipment. NIOT has also undertaken a separate project for the study of area drainage scheme of the Cheyyur power plant area. This work involves field survey, modeling of hydrology and hydraulics and develop a solution for sustained drainage into the sea through the coastal inlet.

NIOT carried out environmental impact assessment for the new jetties proposed to be constructed by the Coast Guard & Indian Navy at Port Blair. The impact of disposal of dredge spoil has been studied for Gujarat Pipavav Port Ltd.

MISSION - IV : Marine Instrumentation

The Marine Instrumentation mission of NIOT is mainly oriented towards the goal of indigenous development of acoustic based instruments for marine and Oceanographic use which includes instruments for special applications such as underwater surveys and tidal level monitoring.

The Acoustic Tide Gauge (ATG) developed by NIOT has reached the stage of commercialization. An IP 65 qualified ATG has been working satisfactorily since April 1999 at Chennai Port Trust along with that of a Sutron gauge, U.S.A. installed in the vicinity. The tide data were validated by the Survey of India (SOI). The Survey Of India and NIOT have agreed to install three more gauges at Kochi, Mumbai and Port Blair. The performance of this gauge compares well with similar gauges from abroad but cost only half of them. Tide gauges with telephone modem facility for remote data logging is under development for installation in other countries in the region.

A beacon lamp with an illuminative power of 80000 mcd for use of signaling the locations of data buoys or any structures situated in sea, has been developed using bright LED array, which are available in yellow or red colours. A prototype acoustic Pinger system has also been developed, integrated with an imported transducer and its performance were successfully tested at 1000m (100 bar) depth. A handheld digital portable current meter is getting ready for field operation from a laboratory model.

NIOT is also involved in the development of some special sensors/ transducers, which form the heart of any marine instrument. A 33kHz underwater transceiver for Echosounder is under development. Individual transducer element has been designed, fabricated and its underwater performance has been successfully evaluated. An array to give a 20deg beam width has been designed, constructed and the laboratory tests are under progress. The NIOT has also under taken development of a 32-element array in the laboratory. Another achievement is the technology demonstration of a single element underwater transmitter operating over a wide frequency range from 500Hz to 12 kHz, for the first time in the country. Further development of such a transducer for using in acoustic sub-bottom profiling application is underway. The development of an Integrated Underwater Survey System (IUSS), which comprises of a 33kHz echo- sounder, 2-16kHz acoustic sub-bottom Profiler and a 190-210 kHz Side Scan Sonar has also been undertaken. The processing software which controls the electronics, communicate to interfacing devices, storage data etc. has been completed. The system design on the hardware part of the total IUSS using a high end DSP has been finalized and the tow body design is under progress.

New campus of NIOT at Pallikaranai, Narayanapuram, Chennai

First phase of construction consisting of technical complex, integration bay, utility building and trainees hostel are completed. Designs for the second phase of construction relating to establishment of acoustic test facility and shallow water harbour basin have been finalised and the preliminary activities for the construction on Acoustic Test facility initiated.