摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A multi-foil lift force creator (1) for a fishing trawl is disclosed, said multi-foil lift force creator comprising a plurality of hydrofoil elements (2) aligned in a stacked manner and designed to be arranged between and attached rigidly at both ends to a spherical buoyancy element (9) for being mounted on a fishing trawl head rope (11), wherein the hydrofoil elements are shaped to deflect the water during towing of the trawl net (12) in such a way that the hydrodynamic force thereby created complements the buoyancy force from the buoyancy elements, and wherein, rather than having butt ends, the hydrofoil elements join smoothly to multi-foil end caps (5) fitting tightly around the two buoyancy elements at the ends of the multi-foil lift force creator, respectively. Furthermore, a multi-foil lift force creator assembly comprising such a multi-foil lift force creator and the use of such multi-foil lift force creator assemblies during trawling operation are disclosed.
摘要:
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.
摘要:
Le dispositif a pour but d'assurer une ouverture satisfaisante du chalut, quelle que soit la vitesse de chalutage, tout en étant fiable et d'utilisation aisée. Il consiste en une structure (11) comprenant au moins deux ailes souples superposées (12, 13) réunies par une pluralité de cloisons (14), transversales par rapport auxdites ailes. Des moyens de fixation (15a, 15b) sont en outre prévus pour gréer la structure sur le chalut, près de l'ouverture, de manière que les ailes soient incidentes par rapport à l'écoulement, et que les cloisons soient orientées dans la direction d'écoulement. Outre d'excellentes performances de sustentation aux vitesses habituelles de chalutage, le dispositif de l'invention a comme avantages d'être très facile à gréer et d'avoir un encombrement négligeable.