A trawl door forms a height and a length and has several curved and overlapping plates including a leading plate which extend in the height direction. The trawl door forms a towing face having a towing bracket and an opposite trawl face having a bridle bracket. The trawl door has at least one regulation means for adjusting a hydrodynamic surface of the trawl door. The regulation means has at least one through opening or at least one cut out, a hatch displaceable in the length direction and a hatch actuator, where the hatch covers the through opening or the cut out when the hatch is in a closed position, and the regulation means is positioned on the towing face of the leading plate.

An arrangement for remotely controlling the position of a trawl door (1) or deflector for seismic surveys comprises an attachment point provided on a movable part (10). The movable part (10) can be moved in relation to a body of the trawl door (1) by means of a remotely controlled actuator. The movable part (10) with the attachment point (15) for a towing line is provided at the body or at a centre rib of the body of the trawl door (1). The movable part (10) with the attachment point can be moved substantially in vertical direction and approximately at right angles in relation to the direction of movement of the trawl door (1) when operated at sea, thereby resulting in an upwards or downwards movement of the trawl door (1) and thereby providing continuous adjustment of depth at which the trawl door (1) operates in the water.

An arrangement for remotely controlling the position of a trawl door (1) or deflector for seismic surveys comprises an attachment point provided on a movable part (10). The movable part (10) can be moved in relation to a body of the trawl door (1) by means of a remotely controlled actuator. The movable part (10) with the attachment point (15) for a towing line is provided at the body or at a centre rib of the body of the trawl door (1). The movable part (10) with the attachment point can be moved substantially in vertical direction and approximately at right angles in relation to the direction of movement of the trawl door (1) when operated at sea, thereby resulting in an upwards or downwards movement of the trawl door (1) and thereby providing continuous adjustment of depth at which the trawl door (1) operates in the water.

A spreading device for trawl fishing, seismic survey operations or other water activities where it is desirable to keep distance between two sides of a towed device is provided, the spreading device having at least one part comprising two or more foils, where each foil has a front surface and a rear surface, the surfaces each being defined by two edges and two side limitations, in use being front and rear edges, an upper and lower side limitations connected to respective upper and lower frames, where at least one foil is stationary and where one or more sections of another foil is pivotably connected to the another foil, such that the section may be moved from a position where the surface of the section is flush with the surface of the another foil, to a position where the surface is out of plane with the surface of the another foil.

A spreading device for trawl fishing, seismic survey operations or other water activities where it is desirable to keep distance between two sides of a towed device is provided, the spreading device having at least one part comprising two or more foils, where each foil has a front surface and a rear surface, the surfaces each being defined by two edges and two side limitations, in use being front and rear edges, an upper and lower side limitations connected to respective upper and lower frames, where at least one foil is stationary and where one or more sections of another foil is pivotably connected to the another foil, such that the section may be moved from a position where the surface of the section is flush with the surface of the another foil, to a position where the surface is out of plane with the surface of the another foil.

A bridle block is for a deflector, and has a stem and a rocker arm attached to each other on a pivot axis. The stem has an attachment for a vessel towline, a forward portion of the rocker arm has an attachment for fore bridle lines of the deflector, and an aft portion of the rocker arm has an attachment for aft bridle lines of the deflector. A hydraulic cylinder has a valve, and is attached to the stem and the rocker arm to hold the stem and the rocker arm in a relative position. The valve is operated by a signal from a control unit. The valve takes an open position when a signal is missing, so there is an open fluid connection between a piston side of a piston and a reservoir or an open fluid connection between the piston-rod side of the piston and the reservoir.

A bridle block is for a deflector, and has a stem and a rocker arm attached to each other on a pivot axis. The stem has an attachment for a vessel towline, a forward portion of the rocker arm has an attachment for fore bridle lines of the deflector, and an aft portion of the rocker arm has an attachment for aft bridle lines of the deflector. A hydraulic cylinder has a valve, and is attached to the stem and the rocker arm to hold the stem and the rocker arm in a relative position. The valve is operated by a signal from a control unit. The valve takes an open position when a signal is missing, so there is an open fluid connection between a piston side of a piston and a reservoir or an open fluid connection between the piston-rod side of the piston and the reservoir.

An arrangement for remotely controlling the position of a trawl door (1) or deflector for seismic surveys comprises an attachment point provided on a movable part (10). The movable part (10) can be moved in relation to a body of the trawl door (1) by means of a remotely controlled actuator. The movable part (10) with the attachment point (15) for a towing line is provided at the body or at a centre rib of the body of the trawl door (1). The movable part (10) with the attachment point can be moved substantially in vertical direction and approximately at right angles in relation to the direction of movement of the trawl door (1) when operated at sea, thereby resulting in an upwards or downwards movement of the trawl door (1) and thereby providing continuous adjustment of depth at which the trawl door (1) operates in the water.

There is provided a spreading device, such as a trawl door used for trawl fishing, and more particularly, a trawl door adapted for stable and efficient operation. The door is equipped with flaps mounted below distal panels and connected to driving units, and the flaps are adapted to be controlled remotely, when the spreading device is being towed through the water; the lower distal panel and the upper distal panel have distal surfaces rendering them hollow, wherein the flaps constitute a part of the distal surface.

There is provided a spreading device, such as a trawl door used for trawl fishing, and more particularly, a trawl door adapted for stable and efficient operation. The door is equipped with flaps mounted below distal panels and connected to driving units, and the flaps are adapted to be controlled remotely, when the spreading device is being towed through the water; the lower distal panel and the upper distal panel have distal surfaces rendering them hollow, wherein the flaps constitute a part of the distal surface.