Morgère France say their aeroplane is the most popular of their mid-water trawls and it has been in use for 14 years since they designed it with the French National Institute for the Exploitation of the Sea (Ifremer). Now they have boosted its capacity.
They make no bones about their expertise in trawls which open trawl horizontally and vertically using a range of depressors, rising panels and kites. They are based on the principle of a double-winged parachute so that the system gives an extra lift to the head line with a reduced drag. The lift is achieved by the water flow circulating between the wing; the drag is only one third of the lift and the quicker you are the more lift you have. The kite is made from a special canvas coated with PVC and it can be rolled with the trawl on the net drum.
The fishing engineers at Irish company Swan Net-Gundry Ltd. are the first to be interested in using the system in big sizes for opening mid-water trawls. "Today the majority of mid-water trawl producers use aeroplane‚ maxi on their products," said Morgère.
In many fisheries the fish move up close to the surface and the aeroplane helps to reshape the trawl when needed.
"We have now finished trials to increase the capacity of the six-metre-wide system called the aeroplane, "monster", which offers more than two tonnes lift at 4.5 knots.
The two aeroplanes are fixed on the head line on both sides of the transducer and give at 4.5 knots one tonne of lift per aeroplane, maxi type, Morgère said.
