Abstract: A marine seismic surveying method and apparatus are shown. The apparatus includes at least one lead-in which has two or more of the streamers connected to be towed thereby, and which comprises a load-bearing outer sheath to bear the towing forces, an electrical or electro-optical core via which control signals and electrical power are supplied to, and data signals are received from, the steamers being towed by the lead-in, and a connector device series connected in the lead-in, the connector device comprising a body member mechanically coupled between the respective portions of the load-bearing outer sheath of the lead-in on either side thereof, to transmit towing forces therebetween, and a towing attachment for mechanical connection to one of the two or more streamers.

Abstract: A device to facilitate the handling, maintenance and replacement of seismic equipment and seismic energy sources in the gun arrangement section, i.e. the gun array of seismic gun cables on seismic survey vessels, on the vessel's after deck (1) by which the gun cables are transferred, with the arrays stored on the deck hanging in suspension rails (6), wherein the cable is wound up on to a number of drums (3) and deployed or recovered from the water over a slip (4) at the after end of the ship. On the deck there are also winch drums (5) for streamer cables. The gun cable drums (3) are placed in a row alongside one another athwartships. Also provided is a row of parallel tracks (6), suspended on rails which can be moved in a crosswise direction. The ends of the rails or tracks (6) are equipped with devices whereby they can be connected to transfer tracks (7) on the slip (4).

Abstract: Release device for a cable used during seismic surveys at sea and towed through the water behind a vessel so that in the event of the occurrence of obstacles or other occasions when it is desirable to release the cable (1) from the towing vessel, a controlled release of the cable is possible so that it is not severed, but can be recovered for further use. At one or more locations in such cables release sections (2) are inserted which contain sensors which sense loading in the section and in the event of overloading or other occasions when release is desirable, an element (5) is activated which cause a release mechanism (6) to be activated and thereby causes a split in the cable (1) at a predetermined location.

Abstract: A bouyancy towed body, especially to be used in marine seismic surveys is assembled from a plurality of modules (1, 2, 3, 4) for adaption to various applications. Modules (1-4) may be locked together, e.g. by through rods (6) provided with tensioning screw and nut devices (8). Modules (1-4) are assembled to form a buoyancy member having a homogeneous surface shape. One (3) or a plurality of modules may be provided with elements (5) for attaching desired equipment thereto which may hang down from the towed body.

Abstract: A fastening device for fixing seismic circular devices is designed with a rigid, split, annular clamp (4) with an open void facing the seismic device (1) for insertion of at least one shock absorbing member (7) in the void. Such a clamp (4) is provided in the region of the device which is most subjected to strain, where a concentric securing ring (8) is also mounted, about which the clamp is fitted with a shock absorbing member (7) on each side of the ring. One more such clamp is provided on the seismic device (1) in order to distribute the load. This arrangement is especially suitable for use in connection with seismic airguns which are to be fixed at predetermined mutual distances in a frame structure (2).

Abstract: A float for use in seismic surveys of the sea bed supports a plurality of seismic pulse transmitters (6) which are suspended on lines (7) beneath the float (1). At a distance from the front end of the float (1), on one sidewall thereof, a fastening device for a towing cable and a lead-in for control lines and lines for supplying operating medium to the pulse transmitters are provided. These lines and cables are gathered in a common line (3) which extends behind the tow ship. The line (3), at a distance away from the float (1), is connected to a line (4) which leads to a length-regulating device (12) inside the front section of the float. The float is also provided with at least one motor (10) with a drive shaft (9)leading to hoisting drums (8) for the lines (7) to the respective seismic pulse transmitters (6). Both the motors (10, 12) and the seismic pulse transmitters (6) are connected to the pneumatic supply line.

Abstract: A cable handling apparatus draws in a cable, such as a seismic streamer, along a generally linear path and feeds the cable to a winch which winds in the cable from the apparatus under constant tension.

Abstract: An arrangement for deployment and towing of a plurality of seismic cables (2) in parallel and at a mutual distance behind a vessel whereby seismic cables (2) are wound on winch barrels (4), and are provided with an inner cable member (3) which forms a connection with the vessel (1) during a towing operations, and is, additionally, provided with a paravane/control (14, 15) to guide and maintain the cable (2) laterally in relation to the towing vessel (1). Reliable and simple depolyment and towing of the seismic cables (2) at a large distance laterally in relation to the center line of the vessel is achieved by running the inner cable member (3) through at least one guide pulley (5) suspended from a line (7) that is adjustable in length from the vessel, and is, preferably extended over a derrick device (9) projecting from the vessel. Guide pulley (5) can be hauled in and paid out from the vessel, at the same time as inner cable member (3) can be let out to a greater length from the vessel.

Abstract: An angular member provided on seismic cables towed by a vessel and laterally displaced in parallel and in relation to the course of the vessel comprises a frame at least partly enclosing the cable in the area of angular deflection between an inner cable portion extending obliquely to the towing direction and the active main cable portion. The frame is formed of two frame plates secured in spaced relationship and having at the lead-in end for the cable a cable-fastening device and at the other end a pivotable ramp swingable in the plane of the frame plates. The ramp has a further fastening device for the cable. Another fastening device is pivotably connected to the frame plates for connecting thereto a wire to a paravane or the like. When towed in the water the angular member absorbs most of the forces normally exerted on the cable at the area of angular deflection.

Abstract: A device for controlling a seismic cable that is towed behind a vessel (1), so that the cable follows a path that is displaced laterally in relation to the path of the vessel, comprises a frame structure (6, 7) extending transversely to the towing direction and outwardly from the area of gun suspension from the cable having longitudinal frame members provided with intermediate transverse members extending obliquely or in a curved manner whereby the front ends of the transverse members, as seen in the towing direction, are disposed further outwards laterally than the rear ends of the transverse members. When towed, the frame will this be forced outwardly by the water flowing through the frame structure and the desired lateral displacement will be achieved.

Abstract: A float for use in seismic surveys of the sea bed supports a plurality of seismic pulse transmitters (6) which are suspended on lines (7) beneath the float (1). At a distance from the front end of the float (1), on one sidewall thereof, a fastening device for a towing cable and a lead-in for control lines and lines for supplying operating medium to the pulse transmitters are provided. These lines and cables are gathered in a common line (3) which extends behind the tow ship. The line (3), at a distance away from the float (1), is connected to a line (4) which leads to a length-regulating device (12) inside the front section of the float. The float is also provided with at least one motor (10) with a drive shaft (9) leading to hoisting drums (8) for the lines (7) to the respective seismic pulse transmitters (6). Both the motors (10, 12) and the seismic pulse transmitters (6) are connected to the pneumatic supply line.

Abstract: An assembly for use in seismic surveys of the sea bed is towed behind a vessel and comprises groups of seismic signal transmitters which are towed through the water, being suspended from float buoys which are combined to form one body which may be formed as a sleeve having limited flexibility. The body is formed with a head member shaped for reducing resistance to the water, and connected to a coupling point for a tow wire to the vessel, which point lies forward of the head member and at the same depth as the transmitters.