Abstract:
Fishing equipment, comprising: a main body; towing means for moving the fishing equipment perpendicular to the longitudinal direction of the main body; and a net, wherein the fishing equipment comprises at least one wing (4, 5), whose orientation in relation to the seabed is controlled by at least one feeler (7, 7') extending from the at least one wing towards the seabed, a first end of the feeler being coupled with the at least one wing, and the other end, during use, freely extending towards the seabed.
Abstract:
A hydrodynamic float element (1) for use with apparatus for "Trawl" fishing by attachment to the head-rope of a trawling net, consists of a body having a leading surface (5) for producing lift during towing and stabilising means, which body has a leading portion (2) providing the greater part of the buoyancy of the element wherein the said body further comprises a trailing portion (3) which is generally flattened and thinner than the leading portion and said trailing portion of the body has a stabilising means (4) extending upwardly therefrom to provide passive directional stability to the float element in use and additional hydrodynamic lift.
Abstract:
A commercial fishing trawl has a net and a mouth opening defined by a head line, a foot line, and side lines. The mouth opening is spread by a plurality of foil segments threaded on one or more of the head line, foot line, or side lines. Foil segments may also be threaded on tag lines or foil lines attached about the mouth opening to spread and maintain the mouth opening as the trawl is towed through the water, behind a tow vessel.
Abstract:
A trawl device that is towed after a trawl vessel, wherein the trawl, for spreading open the opening of the trawl, has an elongate hydrofoil to which the trawl, by its upper transverse length of the trawl opening, is attached, and also has a weight or weights attached to at least one position in the lower part of the trawl opening, for example, the two lower corners of the trawl opening. The device can be used with one or more trawls that are towed side by side, or with two trawls one above the other and fastened to a common trawl.
Abstract:
The purpose of the device is to ensure that the trawl opens satisfactorily whatever the trawling speed, while being reliable and easy to use. It consists of a structure (11) comprising at least two flexible superimposed wings (12, 13) connected by a plurality of partitions (14) transversal in relation to said wings. Securing means (15a, 15b) are also fitted to rig the structure on the trawl near the aperture so that the wings are incident in relation to the flow and so that the partitions are set in the direction of flow. In addition to an excellent lifting action at customary trawling speeds, the device of the invention has the advantages of being very easy to rig and of little bulk.
Abstract:
The invention consists of a method which comprises a plurality of steps for determining difference in distance from a reference point to at least two sensor modules 10, 20 that are located under water. The sensor modules 10, 20 comprise means for sending and receiving acoustic signals to each other and to a hydrophone 30 at the reference point. Connected to the hydrophone 30 is a calculating unit 40 that utilises arrival time of the received signals from the sensor modules to determine difference in distance from the sensor modules 10, 20 to the reference point.
Abstract:
The invention provides a trawl (1) having at least a top and bottom panel comprising self-spreading mesh bars, the trawl including a front end (2) and a back end (3), wherein at least the top panel (4) of the front end comprises an aft front end panel section (6); and a forward front end panel section (5), wherein the aft front end panel section is formed of a self-spreading netting panel, and the forward front end panel section is formed of a netting panel having less outwardly directed lift than the netting panel forming the aft front end panel section. This configuration improves the aspect ratio of the trawl mouth opening, i.e. the horizontal opening is enhanced relative to the vertical opening, and the vertical opening is more uniform, which effects lead to a better maintained back end opening of the trawl.
Abstract:
A system for adjusting a deflector in a seismic survey comprises a generally upright deflector body and at least one bridle connected to a seismic cable. The bridle includes an upper segment secured to an upper connection point on the deflector body, and a lower segment coupled to a lower connection point on the deflector body. The upper bridle segment, lower bridle segment and deflector body define a geometry between themselves. This geometry is adjustable by at least one actuator so as to control the tilt angle of the deflector body
Abstract:
The invention is a device to hold a trawl net open and make it press against the sea bottom. The device consists of a horizontal foot bar (8) to which is attached a vertical wing (10) to create a lateral pulling force on the trawl net. At right angles to the vertical wing (10), a horizontal wing (11) is attached to create a downward vertical force. Both wings are shaped like aircraft wings to utilize hydrodynamic principles for the creation of the above-mentioned forces when the device is being towed in the water. Alternative embodiments may include a device with an aircraft wing profile attached to the vertical wing (10) and a body shaped like a quarter of an egg, the rounded part of which is facing downwards, said body also attached to the vertical wing (10). In the leading edge of the foot bar (8) is a fastening loop (9) for the towing warp (3) coming from the trawler, while in the trailing edge of the foot bar (8) is a bottom warp fastening loop (12), and a top warp fastening loop (13) on the vertical wing. The horizontal wing (11) may be hinged to the vertical wing (10) to allow for vertical movement. A profiled body may also be hinged to the vertical wing (10). The horizontal wing (11) or the egg-shaped body can both be manoeuvred by means of a pneumatic system.