Trawling is a highly energy intensive fishing method and in India about 165.2 million liters of diesel is consumed annually by the medium and large category of trawlers alone. CIFT has developed a few designs of low drag trawls like UHMWPE trawl, cutaway top belly trawl and short body shrimp trawl, for reducing fuel consumption of trawlers.
A pair of otter boards (trawl doors) are required for the horizontal opening of the trawl net. About 20% of the trawl drag (hydrodynamic resistance) is contributed by the otter boards in a trawl system. Slotted otter boards are known for less drag due to water flow through the openings in the boards. CIFT has recently introduced an innovative V-form double slotted otter board for reducing the drag and fuel consumption.
Experiments onboard CIFT research vessel and commercial vessels revealed that depending on the sea conditions 2-3 liters of diesel can be saved per hour of trawling, compared to the existing boards of same dimensions. The new technology has been readily accepted by the trawl owners and several trawlers in Kerala, Tamil Nadu and Karnataka have already started using the new otter boards.
About 20 million liters of diesel can be saved annually in India if all the medium and large category trawlers adopt this technology. Further it helps to improve the income of fishermen and also reduce the emission greenhouse gases, which are the two most important needs in the fisheries sector globally.