122 results about "Trawling" patented technology

The invention discloses a motor twin trawling platform used for a motor test. The motor twin trawling platform used for the motor test comprises a transformer, a rectifier, a filter, a tested motor, a master control system, a load motor, a coupler and two motor control systems. The rectifier is connected with the transformer, two ends of the filter are respectively connected with two output ends of the rectifier, a tested motor control system and a load motor control system are both connected with the filter, the load motor is connected with the load motor control system, a tested motor output shaft is connected with an output shaft of the load motor through the coupler, and the tested motor control system and the load motor control system are both connected with the master control system. The whole system of the motor twin trawling platform used for the motor test can be miniaturized, the motor can be output through random torque so as to enable the motor twin trawling test to be diversified, electricity is saved, and efficiency can be obviously improved.

To provide a winding mechanism and a trawling apparatus capable of eliminating an excessive tension or slack generated in a wire wound around a drum and keeping the tension or wire length of the wire constant.A winding mechanism with tension control function includes a reversibly rotatable liquid-pressure motor rotating a drum having a wire wound therearound, a liquid-pressure pump coupled directly with the liquid-pressure motor and supplying hydraulic oil, and an electric motor rotating to drive the liquid-pressure pump. The winding mechanism further includes a control unit controlling a torque of the electric motor based on a variation in load current of the electric motor and winding off or winding up the wire to keep the tension of the wire at a set value.

The invention relates to a technology of absorbing fish by a cod end used for the trawl fishing of a large distant-water trawler, and belongs to the fields of farming, forestry, husbandry, and fishing. During a good harvest fishing time, large net heads of large trawlers used for catching scads in the south pacific and catching haddock in the north pacific can be frequently used for catching 500-600 tons fishing goods by a single net, and the weight of caught fishing goods by a single net sometimes can even reach up to 800 tons. Each large net head contains too many fishing goods, so that the fishes in each cod end are impossible to be directly pulled on a deck of the trawler. The technology of absorbing fish by cod end adopts an axial-flow type fish absorbing pump driven in a hydraumatic manner to directly absorb fish in the cod end into a fishhold of the trawler.

The invention discloses a fishing-oriented unmanned ship group collaborative self-organizing work system and an implementation method of the system. The method comprises the steps that an unmanned ship group collaborative self-organizing fishing work mechanism is established through the unmanned ship group collaborative self-organizing work system; unmanned ships are accurately positioned by using the master unmanned ship and slave unmanned ship collaborative navigation positioning technology; and a collaborative search strategy and a collaborative path tracking strategy are formulated according to the work area and the work environment, and fish finding, fish shoal tracking, net trawling and net drawing work can be completed according to the strategies. The system and the method are based on the radio communication system of the radio station and based on the multi-sensor integration measurement and control system of the CAN bus, all the unmanned ships collect environment and position information through a sensor integration system and then exchange data through the communication system and perform collaborative control.

The invention discloses a dragnet with a plurality of serial bags and fishing method using the dragnet. The dragnet comprises a net wing, a net body and a net bag. The net bag comprises the plurality of bags which are serially connected end to end and frame. Each frame is provided with a front-rear frame open-close device, a bag separating device and a controller. By the arrangement, fish captured by the dragnet can be gathered in corresponding bags in batches, separated from the net body along with the bags, and dragged and lifted to a fishing boat, the problems of pressing, scratch, death even deterioration, caused by long-term trawling, of the captured fish are solved, survival rate and freshness quality of the captured fish are increased, and power of a fishing boat winch can be relieved due to lifting in batches and light bags.

The invention provides a testing device for a twin trawling-loaded low-speed motor. The testing device comprises a base, wherein a torque sensor and a trawled motor as a load are arranged on the base; the trawled motor comprises a rotary encoder or a grating structure for determining the rotating speed of the motor. The trawled motor, the torque sensor and the tested motor are connected together by a coupling. A sensor for determining the change of current and voltage, a corresponding test circuit of the sensor, a slide rheostat which is connected with the trawled motor and is used for dynamically changing the load, a test circuit power supply and the like are also arranged on the base. The testing device can communicate with PC (Personal Computer) software through an RS232 communication interface. According to the testing device disclosed by the invention, accurate and stable measurement of various dynamic parameters of a low-speed motor including rotating speed and torque can be realized; and the testing device is small in size and wide in application range.

A system for reducing trawl bycatch through the use of a “flying”, “steerable” element of a towable or trawlerable fishing net, consisting of one or more hydrofoils at the mouth of the net, which maintains either a consistent height over the seabed or a pre-determined depth in the water, semi-autonomously. This negates the need, per the prior art in trawling and fishing technology, for heavy rollers on the bottom of the net, or heavy side “doors”. The present-day use of prior art ruins the ecosystem directly through physical damage to coral, sea bed hatcheries, etc., and indirectly by requiring increased fuel use on the trawling vessel and thus creating more emissions. This invention addresses those problems providing a better, cleaner and less destructive technology for fishing.

The invention discloses an anchored bentonic organism acquisition system and an acquisition method thereof, and aims at providing an anchored bentonic organism acquisition system for effectively acquiring bentonic organisms inhabiting on the surface of seabed, and an acquisition method thereof. The system comprises a trawling box, a mooring anchor and a winch arranged on a ship body; the winch comprises a vehicle frame, a first reel and a second reel rotatably arranged on the vehicle frame, a first rotating device used for driving the first reel to rotate, a dragging rope reeled on the first reel, a second rotating device used for driving the second reel to rotate, and a releasing rope reeled on the second reel; the output shaft of the first rotating device is connected with the rotating shaft of the first reel through a first clutch; the output shaft of the second rotating device is connected with the rotating shaft of the second reel through a second clutch; the free end of the dragging rope is fixed on the trawling box; and the free end of the releasing rope is fixed on the mooring anchor, the top of the anchor bar of the mooring anchor is provided with a guide ring, and the dragging rope traverses through the guide ring.

A method and system for efficient and eco-friendly shrimp skimmer trawling by a trawling vessel with a trawl net, skimmer booms, net arms, and buoyantly adjustable rollers to maintain trawl net height and net opening without damage to the ocean floor allowing for systematic and frequent retrieval of catch while continuing trawling operations in intervals short enough to prevent death of by-catch and endangered species and where the system is fully storable on trailerable trawling vessels for maintenance of allowable highway heights. The system and method has the upper edge of the trawl net held above the ocean surface while the trawling vessel moves forward.

The invention relates to a high-aspect-ratio double-arc surface-middle layer trawl board which comprises a main panel, wherein the main panel is in a vertical double-arc structure; a cross section is double-arc internal hollow; an upper top board is mounted at the top of the main panel; a lower top board is mounted at the bottom of the main panel; a middle reinforcing board is mounted in the middle of the main panel; reinforcing rib boards are mounted between the upper top board and the middle reinforcing board, and between the middle reinforcing board and the lower top board respectively; the upper top board, the middle reinforcing board, the lower top board and the reinforcing rib boards divide an inner space of the main panel into four watertight spaces; a guide board is mounted on the front side of the main panel; a tow rope connecting frame is mounted at one end, close to the front side, of the middle reinforcing board; a cross rope connecting frame is mounted on the main panel close to the top of the rear side of the upper top board at the top, and close to the top of the main panel; and cross rope connecting frames are mounted at the rear end, close to the upper top board and the lower top board, of the main panel. The high-aspect-ratio double-arc surface-middle layer trawl board is located on a target water layer, has a greater expansionary force and smaller water resistance, and is applicable to surface-middle layer trawling.

The invention relates to a chain SVG (Static Var Generator) module test system, platform and method. The test system comprises the test platform and at least two SVG modules, wherein the test platform comprises a control circuit part and a main circuit part. The test system has a low voltage level, is easy to operate, and has small system loss; testing can be performed by twin trawling of two H bridges without simultaneous running of the H bridges of an entire chain SVG, and a large amount of reactive power is prevented from being exchanged with a power grid.

A trawling vessel is provided with a trawl net (5) for catching marine bio-resources, with a trawl sack (3) attached aft on a trawl net (5) for keeping the catch. The vessel comprises lines (51, 61) for towing and hauling the trawl net (5), and trawl drums (6) for hauling the trawl net (5). A lock chamber (1) is provided in a stern (21) of the vessel and has a main portion of its volume arranged below the design water line of the vessel. The lock chamber (1) is arranged for hauling the trawl sack (3) with the catch from the sea through a sluiceway (2) in the stern (21), for discharging the trawl sack (3), and for temporarily keeping the catch. A trunk channel (16, 12) leading up from the lock chamber (1) enables the trawl sack (3), in a generally discharged state, to be hauled up through the trunk channel (16, 12) to a deck (24), thereby leaving the catch in the lock chamber (1).

The invention provides a trawler and belongs to the technical field of ships. The trawler comprises a hull structure and two trawling arm frames. The lower ends of the two trawling arm frames are hinged to the two sides of the hull structure. Floating mechanisms are arranged at the tops of the trawling arm frames and comprise floating boxes. Expandable airbags are arranged on the lower sides of the floating boxes. Electric air pumps are arranged on the upper sides of the floating boxes and connected with the expandable airbags through pipes. Floating bodies are arranged at the lower ends of the expandable airbags. First through holes are formed in the peripheries of the floating boxes. Slide rods are inserted in the first through holes. Baffles are arranged at the upper ends of the slide rods, and the sizes of the baffles are larger than the sizes of the first through holes. The lower ends of the slide rods penetrate through the first through holes, and the floating bodies are hinged to the ends of the slide rods. Reset springs are arranged on the slide rods and located between the floating bodies and the floating boxes. The floating mechanisms in the trawler plays a good role in supporting the trawling arm frames in trawling operation of the trawler, so that the safety of trawler operation is improved.

The invention discloses a fishing method using a mesopelagic trawl easily crossing an obstacle, and aims to solve the problems that in the mesopelagic trawling process, netting is easily torn, and a foot line is seriously abraded, so that mesopelagic fishing operation is seriously affected. During trawling, a towing warp is connected to a fishing boat, the whole trawl is casted into seawater, thetrawl goes down into the seawater, and the fishing boat drags the trawl to move forwards to catch fishes. When the trawl comes across an obstacle, rolling wheels connected to a crossing frame on the foot line of the trawl make contact with the obstacle first and roll over the obstacle, the crossing frame rotates to release impact energy, meanwhile, a withstanding plate moves towards an installation sleeve so as to drive a whole telescoping rod and the foot line to be bounced upwards, and the obstacle is crossed. After a certain time, the trawl is drawn in the fishing boat to obtain the fishes.

The invention belongs to the technical field of mechanical equipment reliability testing, and particularly relates to a motorized spindle reliability test bed based on twin trawling loading. The testbed comprises spindle installing parts, a mechanical loading part, a status monitoring part and a circuit control part. According to the spindle installing parts, due to V-shaped structure positioning, the spindle installing part A and B and horizontal iron are matched and adjusted, and positioning and centering between motorized spindles of different outer diameters can be achieved. According tothe mechanical loading part, a main loading block and a slave loading block transmit torque through conical surface contact, additional radial force and additional axial force are generated at the same time, and the actual tool cutting working condition can be simulated. According to the status monitoring part, the status of the motorized spindles is monitored by installing sensors on two supports. According to the circuit control part, a direct current bus is adopted between a frequency converter A and a frequency converter B for feeding back current to achieve the energy recycling purpose. The problems that an existing motorized spindle reliability test bed is poor in reliability, low in testing efficiency, high in testing cost and the like are solved.

To provide a winding mechanism and a trawling apparatus capable of eliminating an excessive tension or slack generated in a wire wound around a drum and keeping the tension or wire length of the wire constant.A winding mechanism with tension control function includes a reversibly rotatable liquid-pressure motor rotating a drum having a wire wound therearound, a liquid-pressure pump coupled directly with the liquid-pressure motor and supplying hydraulic oil, and an electric motor rotating to drive the liquid-pressure pump. The winding mechanism further includes a control unit controlling a torque of the electric motor based on a variation in load current of the electric motor and winding off or winding up the wire to keep the tension of the wire at a set value.

The invention relates to a method for trawling live young fishes, which includes: reserving holes close to an opening of a barrel on the barrel; mounting the barrel at a rear sack of a trawl net; performing trawling in natural waters by single boats; and hauling the trawl net to collect young fishes captured in the barrel. By the method, high stress and injury by transient anoxia after the fishes leave water can be prevented, and the survival rate of the young fishes caught by trawling can be increased evidently.

The invention provides a loss test system and method for a flexible DC transmission converter valve based on a valve section twin trawling test platform, and the system comprises a valve section twintrawling module, a loss calculation module and a current control module, wherein the current control module receives a real-time current value of the valve section twin trawling module, and outputs acontrol signal to the valve section twin trawling module to generate a stable running current in the twin trawling module; and the loss calculation module receives the voltage and current measurementdata of the valve section twin trawling module, and calculates the loss of the test valve section and the accompanying test valve section in the valve section twin trawling module. The total loss in the valve section twin trawling platform is provided by the DC power outputted by the supplemental power supply, so that the power consumed by the valve section twin trawling platform can be accuratelycalculated, and the problem that the loss of power is difficult to accurately measure by the AC power supply mode is avoided. In addition, active loss of the reactor at multiple frequencies is takeninto account for the loss generated by the load reactor in the loop, which can further ensure the accurate loss calculation of the converter valve.

The invention relates to a trawler propulsion technology, and in particular relates to a converter used for electric propulsion of a trawler which can be used for solving the problems of poor maneuverability, poor emergency capability, poor dynamic performance, large power loss, poor equipment selection flexibility and poor operating economy of the trawler caused by an existing diesel propulsion system. The converter used for electric propulsion of the trawler comprises a three-phase bridge type uncontrollable rectification circuit, a pre-charging circuit, a filtering circuit, a braking circuit, a discharging circuit, an inversion circuit and a detection circuit, wherein the three-phase bridge type uncontrollable rectification circuit consists of first to sixth rectification diodes, the pre-charging circuit comprises a pre-charging contactor, a pre-charging diode and a pre-charging resistor, the filtering circuit comprises a filtering inductor and a filtering capacitor, and the braking circuit comprises a braking IGBT (Insulated Gate Bipolar Translator), a braking resistor, a fuse and a buffering capacitor. The converter is applicable to the trawler.

The invention discloses a horizontal expansion device for a Euphausia superba trawl net. The horizontal expansion device comprises a vertical 'V'-shaped curved net plate which comprises an upper cross rope plate, a front flow guide plate, a rear flow guide plate, a towing warp pulling plate, inter-plate reinforcement plates, a lower cross rope plate, a trawling iron attachment plate, trawling iron, a middle towing warp plate, a front main panel, a rear main panel, an upper balance plate, pulling holes of the upper cross rope plate and pulling holes of the lower cross rope plate. The horizontal expansion device is characterized in that an aspect ratio of the 'V'-shaped curved net plate is larger than or equal to 2.7; the towing warp pulling plate which is welded to the middle towing warp plate is in longitudinal arrangement and provided with five towing warp pulling holes in longitudinal array, and the towing warp pulling holes are connected with towing warps through towing warp shackles; the rear side of the upper cross rope plate of the 'V'-shaped curved net plate is provided with six pulling holes of the upper cross rope plate, the rear side of the lower cross rope plate is provided with six pulling holes of the lower cross rope plate, and the pulling holes of the upper cross rope plate and the lower cross rope plate are in corresponding connection with an upper cross rope strand and a lower cross rope strand through cross rope shackles. The horizontal expansion device is especially suitable for low-speed Euphausia superba trawl nets.

The invention provides a microgrid-simulation variable-power asynchronous motor load experiment platform and belongs to the technical field of motors. The microgrid-simulation variable-power asynchronous motor load experiment platform comprises a motor twin trawling platform, a master control cabinet and a resistor cabinet with an adjustable resistance value, wherein the motor twin trawling platform comprises an asynchronous motor, a synchronous power generator and a coupling; the master control cabinet comprises a PLC (Programmable Logic Controller), a touch screen, a dragging motor soft starter and a power quality testing instrument. According to the microgrid-simulation variable-power asynchronous motor load experiment platform, load power can be set through the PLC based on simulating no-load and load operation of the asynchronous motor, the microgrid-simulation variable-power asynchronous motor load experiment platform is simple in structure, good in stability and reliability and convenient to use, avoids complex operation procedures like a machine set, can achieve soft start in zero torque (zero rotation speed), completely avoids impact of machine set start to a power grid, solves load operation only by adjusting resistance through controlling the touch screen, is very convenient to use and keeps very high stability in whole journey rotation speed (even zero rotation speed) and torque range.

The invention discloses a single boat trawling semi-flexible foldable rectangular V-shaped otter board. The single boat trawling semi-flexible foldable rectangular V-shaped otter board comprises two rectangular rigid frames capable of rotating freely around a center shaft, wherein a cross rope connection point is arranged on each of the two rigid frames; the rigid frames are provided with two or more windows; the windows are provided with light water-impermeable flexible otter board surfaces; a plurality of length-adjustable rigid support rods stretch the two rigid frames, so that the stretched two rigid frames form a V-shaped structure with an adjustable included angle; the center shaft is provided with a perforated warp fixing sheet. By adopting the single boat trawling semi-flexible foldable rectangular V-shaped otter board, the weight of the rectangular V-shaped otter board is reduced, damage of the otter board to the seabed ecological environment is reduced, dragging resistance is reduced, and energy consumption in a fishing boat operation process is lowered; moreover, the single boat trawling semi-flexible foldable rectangular V-shaped otter board is simple in structure, is convenient for transportation, operation and assembly, is low in cost, and can be assembled and detached rapidly; damaged parts can be replaced rapidly in an operation process, and efficient, low-energy-consumption and environment-friendly fishing in single boat trawling operation is realized; the single boat trawling semi-flexible foldable rectangular V-shaped otter board can be widely applied to offshore small-sized single boat trawling fishing boat operation in China.

The invention relates to a self-energized up and down adjusting equipment for euphausia superba beam trawling. The equipment includes a pair of up and down adjusting devices symmetrically arranged ona beam. Each of the up and down adjusting devices includes a fairing, a protective cover, a propeller water current generator, a bidirectional driving motor, a rotary screw, a lifting and lowering connector and a fin. The protective cover is connected with the rear end of the fairing. The propeller water current generator is arranged inside the fairing. The bidirectional driving motor is driven bythe propeller water current generator. Two ends of the rotary screw are arranged on the protective cover, wherein the two ends are along the vertical direction and can rotate bidirectionally. The rotary screw is driven by the bidirectional driving motor. The lifting and lowering connector is arranged on the rotary screw in a thread structure. The front end of the fin is horizontal and both sidesof the fin are rotationally connected with the protective cover separately. The rear end of the fin is connected with the lifting and lowering connector and is driven to adjust the angle of the fin through the lifting and lowering movement of the lifting and lowering connector. The self-energized up and down adjusting equipment provide by the invention can realize the controllable and self-energized active lifting and lowering adjustment of the beam trawling.

The invention discloses a euphausia superba trawling bird frightening rope which consists of a braided rope, a rotating ring, colored flags or colored ribbons, and a steel loop, and is characterized in that one end of the braided rope is connected with the rotating ring; the steel loop is tied to the other end of the braided rope; the colored flags or the colored ribbons are fixedly distributed on the braided rope along the braided rope; the distance of the colored flags or the colored ribbons distributed on the braided rope is greater than the length of each colored flag or colored ribbon. The invention is used for improving the effect of a bird frightening rope and protecting sheathbills, and thus the seabirds can be prevented from accidental injury.

The invention aims to provide a feed additive for improving the anti-stress capability of large yellow croakers. The feed additive comprises procyanidine and a vitamin C additive, wherein the mass ratio of procyanidine and the vitamin C additive is preferably (0.5-2):1. The additive amount of procyanidine in the anti-stress additive of large yellow croakers is 100-300mg / kg, and the additive amount of vitamin C phosphate is 500-600mg / kg. The procyanidine and the vitamin C additive combined in the proportion can be used for improving the anti-stress capability and anti-trawling stress capability of the large yellow croakers and does not generate obvious side effects on livers of large yellow croakers.

The invention discloses a method for modeling a single mid-water trawl net system in a fishing vessel operating simulator. In the method, a mathematical model of the single mid-water trawl net system is divided into a trawler mathematical model and a fishing gear system mathematical model, the fishing gear mathematical model is divided into a trawl net mathematical model and a netting gear system mathematical model, and the coupling between the models is realized by utilizing boundary conditions. The method comprises the following steps: firstly, establishing a maneuvering mathematical model of a trawler; secondly, respectively establishing the trawl net mathematical model and the netting gear system mathematical model by a finite difference method and a lumped mass method, and realizing the coupling of the two by utilizing the boundary conditions between the models; and finally, realizing the coupling between the trawler mathematical model and the fishing gear system mathematical model by utilizing the boundary conditions to embody mutual influence of the two. The method can correctly reflect the interaction of a fishing vessel and a fishing gear system, dynamically simulate a net casting and drawing process of the fishing vessel, and also can embody the influence of the length change of the trawl net on the trawling position in the fishing process.

The invention discloses a device and method for rapidly separating and extracting micro-plastics in surface water, and belongs to the technical field of environment monitoring. The device comprises afloating platform, a lifting rod, a filter cartridge, a dissolution tank, a waste liquid tank and other main devices. The device and method for rapidly separating and extracting the micro-plastics ofthe water body on the surface layer have the advantages that under the premise that large-area trawling of a sampling boat is not needed, a large number of water samples are filtered in a sampling area, the workload during sample collection is effectively reduced, and the efficiency is improved; the device for rapidly separating and extracting the micro-plastics is integrated with a water sample filter and dissolution module, thereby being capable of achieving in-situ preliminary dissolution of a filter membrane, saving time for the subsequent dissolution step in a laboratory, and also reducing the possibility that samples are contaminated by the environment during processing, so that monitoring results are more accurate and reliable.

The invention discloses an elastically-supported flexible trawling selection device. According to the invention, the problems of rigid trawling selection devices can be overcome, so that the trawling selection device can be well connected with the flexible webbing of a trawl net. The elastically-supported flexible trawling selection device comprises a rectangular frame, and isolating bars which are arranged between the upper and lower borders of the frame and are in parallel to the left and right borders of the frame. The elastically-supported flexible trawling selection device is characterized in that the rectangular frame is a supporting frame in which high-hardness springs are utilized as the upper, lower, left and right borders; elbows and the high-hardness springs are welded at the four corners of the frame; ultrahigh-strength low-extension long rope cores are arranged inside the high-hardness springs serving as the upper and lower borders and connected with the metal elbows at the two ends of the upper and lower borders; nylon corrugated hoses are sleeved outside the high-hardness springs serving as the four borders; the isolating bars are made of elastic tubes; each elastic tube consists of a high-hardness spring and a silicone rubber hose sleeved outside the spring; the positions of the elastic tubes are fixed through ultra-high molecular weight polyethylene ropes which are parallel to the upper and lower borders and connected with the left and right borders; and the two ends of the individual high-hardness springs of the elastic tubes are connected with the nylon corrugated hoses of the upper and lower borders through quick connectors. The device is applied to the selective trawling operation.

The invention belongs to the field of deep-sea technologies and relates to a deep-water contactless trigger switch. The deep-water contactless trigger switch comprises a solid state electronic contactless switch element and a switch body, wherein the solid state electronic contactless switch element is sealed in the switch body. The deep-water contactless trigger switch is characterized by further comprising a small watertight connector, a front end cover, an O-shaped sealing ring, a back end cover and a magnet; axial and radial dual-seal structures are adopted on the contact place of the front end cover and the switch body and the contact place of the back end cover and the switch body, and the axial direction and the radial direction are both sealed by the O-shaped sealing rings. According to the deep-water contactless trigger switch, the problem of deep-sea high-pressure sealing is effectively solved, so that the deep-water contactless trigger switch is safe and reliable; a deep-sea small watertight connector allowing wet plugging under the water is provided for adapting to requirements of the deep-water severe environment, and the maximum working water depth is up to 14000 m; the deep-water contactless trigger switch can be applied to multilayer trawling of abyssal plankton and deep-sea detection and sampling devices, such as submarine sediment acoustics in-situ detection systems.

The invention discloses a large-field-angle trawling gear. In the Large-field-angle trawling gear, a steering device which can be used for driving a water body to change the heading direction of a suspension plate is inserted into the suspension plate; the suspension plate further is connected with a trawling rope; the free end of the trawling rope is connected to a trawling ship in which a positioning device is arranged; the top of the suspension plate is connected with a floating body; and a positioning antenna is arranged on a floating body. The positioning device on the trawling ship is communicated with the positioning antenna, and the relative positions of the positioning device and the floating body are calculated through triangular positioning, so that decision information is provided for the running of the steering device. The running of the steering device is controlled according to the positioning of the positioning device for changing of the heading direction of the suspension plate in water and changing the field angle of the trawling rope connected with a trawling net behind, so that the size and the opening direction of the mouth of the trawling net are controlled indirectly, the aim of operating one trawling net by using a single ship is fulfilled, more energy is saved, and the efficiency is higher. The large-field-angle trawling gear has the advantages of novel structure, rapid change in the field angle, saving in energy and high efficiency.