Abstract: A robust air gun fire time sensor consists of a housing to which is secured a protruding nonmagnetic internal barrel having a bore. The bore is closed at one end by a magnetic end cap defining an air chamber and the bore is in fluid communication with the firing chamber of an air gun. A generator coil surrounds the barrel. A bar magnet is floatingly mounted inside the bore and is urged against a shoulder formed in the end cap. When the air gun is charged with compressed air, some of the air becomes entrapped in the air chamber. When the air gun is fired, the entrapped compressed air in the air chamber pushes the bar magnet away from the shoulder. The collapsing magnetic field creates a transient electric pulse in the generator coil.

Abstract: A hermaphroditic submarine cable connector link for a multisection seismic marine streamer cable includes identical end fittings mounted at each end of a pair of adjacent cable sections. Identical connector plates are coupled to electrical conductors at each end of the sections. The connector plates from the pair of adjacent cable sections are mated and then linked to the end fittings. A barrel is slipped over the end fittings and around the mated connector plates. The end fittings are locked by the barrel in spaced-apart relationship, employing a ball-and-detent locking arrangement.

Abstract: A coupler for connecting two seismic streamer sections together consists of a two-part hollow quick-disconnect fitting. The fitting has an internal diameter sufficient to contain a multicontact connector strip for electrically interconnecting the signal wires from the two streamer sections. When assembled the two parts of the housing are non-rotatable with respect to each other.

Abstract: A marine seismic streamer-cable section includes a plastic tubular jacket reinforced by tough, braided-fiber tapes embedded in the jacket wall. A termination fixture is fastened to each end of the cable section. The termination fixture includes a bulkhead, an untapered end of which fits snugly into the plastic jacket. The other end of the bulkhead is tapered and protrudes from the end of the jacket. Short lengths of the reinforcing tapes are exposed by stripping away some of the jacket wall. A cylindrical wedge grips the exposed tapes between the inner wall of the wedge and the tapered portion of the bulkhead. The tapes are doubled back over the outside of the wedge and are bound to the jacket and to the untapered end of the bulkhead by bands.

Abstract: A method for seismic prospecting in a body of water which comprises trailing a gun adapted to initiate explosively-operated charges at a sufficient depth below the water's surface to allow the creation in the body of water of high-pressure waves, and detecting the pressure waves with a detector assembly including a housing having a flexible, sound-transmitting wall defining a chamber, an incompressible liquid completely filling the chamber, and a detector probe completely immersed in the incompressible liquid.

Abstract: The underwater charge launcher linearly ejects a small, water-propelled explosive charge into the water from the open end of an ejection barrel trailed in the water behind a seismic exploration vessel. The charge is detonated, after a one to two-second delay, when a percussion-ignitable delay cap in the end of the charge impacts a firing member positioned adjacent the open end of the ejection barrel. The firing member includes a firing pin mounted on a rotatable, spring-biased striker plate having a U-shaped rim. When a charge is ejected from the barrel, the primer cap impacts the firing pin. The kinetic force of the ejected charge acting against the firing pin overcomes the moment of inertia of the striker plate, causing it to rotate the firing pin out of the path of the charge. The charge is supported and guided by the unobstructed portion of the U-shaped rim of the striker, as the charge is ejected out of the launcher. After a preset delay, the charge detonates when it is a safe distance from the launcher.

Abstract: A method and apparatus for seismic prospecting in a body of water which comprises trailing a gun adapted to initiate explosively-operated charges at a sufficient depth below the water's surface to allow the creation in the body of water of high-pressure waves, and detecting the pressure waves with a detector assembly including a housing having a flexible, sound-transmitting wall defining a chamber, an incompressible liquid completely filling the chamber, and a detector probe completely immersed in the incompressible liquid.

Abstract: The underwater gun assembly of this invention has an acceleration barrel and a firing gun. Percussion-initiatable cartridges are carried to the acceleration barrel by a stream of water. Each cartridge has an outside diameter which is nearly equal to the inside diameter of the bore in the barrel whose length is such as to allow the water pressure to optimally accelerate each cartridge in its trajectory through the barrel. The firing gun is detachably coupled to the barrel by a quick-disconnect coupling means. The detachable coupling means preferably includes a non-metallic resilient member which absorbs the shock waves from the ambient charge explosions, thereby preserving the integrity of the coupling means in respect of its detachable characteristics.