Abstract: A weight block for a marine seismic cable comprises a heavy weight member with a soft, overlying layer. The weight block is bolted, hinged, or otherwise attached to the cable to provide desired ballast. The outer covering of the weight block is molded over the inner metal member with an injection molding machine or other standard techniques. The inner diameter of the molding on the block may have a plurality of ribs with a smaller diameter than the nominal diameter of the solid-filled or liquid filled cable.

Abstract: A solid marine seismic cable assembly includes a cable, hydrophone housings, a buoyant filler, and an outer protective jacket. The cable includes a load-bearing fiber bundle, data-transmitting wires, power conductors, optical fibers, and a protective sheath. The data-transmitting wires, power conductors, and optical fibers surround the load-bearing fiber bundle. The protective sheath surrounds the assembly of the data-transmitting wires, power conductors, optical fibers, and the load-bearing fiber bundle. The hydrophone housings affix around the cable in a spaced-apart relationship. Each hydrophone housing includes a hydrophone module, and each hydrophone module contains a hydrophone. The buoyant filler surrounds the cable, and separates the hydrophone housings. The outer protective jacket surrounds the hydrophone housings and the buoyant filler, enclosing the cable assembly.

Abstract: A low-profile hydrophone module for a marine seismic system includes a block having a curved surface and a receiving surface in which an open cavity is disposed, a hydrophone assembly, to which lead wires attach, disposed in the cavity, lead wires which pass out of the cavity, and a sound-transmitting material which fills the cavity. In another feature, the hydrophone assembly includes a hydrophone and a baffle material, the baffle material enclosing the hydrophone, the cavity is sealed around the lead wires, the sound-transmitting material is oil, and a cover sealingly affixes over the cavity. In another feature, the hydrophone assembly includes a hydrophone and a frame, the cavity is sealed around the lead wires, the sound-transmitting material is a potting sealant, and a cover sealingly affixes over the cavity.

Abstract: A hydrophone housing includes a hydrophone module, or cap, which contains a hydrophone. The hydrophone housing clamps around a marine seismic cable. The hydrophone housing farther includes a first portion and a second portion. One of the portions has a receiving recess, The hydrophone cap installs on this receiving recess. The portions each include a contact surface which contacts the cable when the portions fasten around the cable. The portions clamp around the cable via screws, The contact surface includes raised bosses which securely grip the cable by increasing contact pressure per unit area in a region of contact between the raised bosses and the cable.In another feature, the portion which contains a receiving recess further includes a wire-clearance recess and a wire passageway, between the receiving recess and the wire-clearance recess.In another feature, an outer cylindrical surface of each hydrophone cap is flush with an outer cylindrical surface of each hydrophone housing.

Abstract: The disclosure relates to a seismic vibrator having an airbag isolator, a transducer for monitoring the instantaneous air pressure within the airbags, a summer to add the pressures within each air bag and a calibrated weighting network to convert the composite pressure for display as holdown weight on a meter and for comparing the measured holdown against a preset threshold that is used to enable or disable sweep generation or operation of an inducer. The system also includes structure for comparing the measured holdown against a preset threshold that is used as a feedback signal to the lift system and for providing a signal proportional to holdown weight to the sweep generator for use as a feedback signal to modify the amplitude of the force generated by the actuator.