A control system for a towed object (1, 6; 20; 30; 50) in or on a body of water comprise one or more towing members (3) extending between the object (1) and a towing vessel (2). One or more ballast members (4) are movably connected to a respective one of said one or more towing members (3) and controllably movable at least a distance along its respective towing member. The towed object (1) may be controlled by moving one or more ballast members (4) on a towing member (3) in order to control the catenary (c) of a towing member (3). Individual ballast members (4) may be manipulated individually in order to correct, preserve or otherwise change the geometry of a trawl.

A sonar system includes a towfish comprising a first body linked to a second body, the first body being elongate along a longitudinal axis and comprising a plurality of acoustic transmitters distributed along the longitudinal axis, the sonar system comprising a cable linked to the second body and via which a surface carrier ship is intended to tow the towfish, the first body being mounted to pivot, with respect to the second body, about an axis of rotation so that, the first body can switch, by pivoting with respect to the second body about the axis of rotation, from an operational position to a capture position; the axis of rotation being substantially an axis of movement of the towfish, the longitudinal axis being substantially vertical in the operational position of the first body and being substantially horizontal in the capture position of the first body, when the towfish is totally submerged and towed by the carrier ship.

A stable towable submersible device includes a rigid body that is towed at a positive pitch angle relative to the device's direction of motion. An acoustic projector housing extends vertically from the rigid body. When the rigid body rolls about its roll axis, which is tilted at the positive pitch angle, the acoustic projector rolls about the roll axis changing the acoustic projector's angle of attack relative to the direction of motion and generates a restoring force causing the acoustic projector to rotate back to a generally vertical orientation.

A foil for a towed cable includes a body defining at least two conduits. The body has a foil shape having a leading edge and a trailing edge. The foil shape defines a first surface extending between the leading edge and the trailing edge configured to provide lift. The foil shape defines a second surface opposed to the first surface extending between the leading edge and the trailing edge. The foil shape defines first and second lateral sides that extend between respective lateral edges of the first and second surfaces, the leading edge, and the trailing edge. A first conduit is defined within the forward half of the body adjacent to the leading edge, is open to each of the first and second lateral sides, and is configured to receive a cable therethrough. A second conduit may be defined within the body and filled with buoyant material.

A faired towing cable employed on a ship for towing a submersible body launched at sea is provided. The cable comprises a core and a fairing joined to the core. The fairing is profiled so as to reduce the hydrodynamic drag of the cable. The fairing comprises several leading edges and several trailing edges joined to the leading edges. One trailing edge is held directly on two adjacent leading edges.

Embodiments herein include a fairing for a marine seismic array system that includes a foil having a leading edge and a trailing edge and defining a chord length and a span length, a first interior conduit oriented along the span length aft of the leading edge, and a second interior conduit oriented along the span length forward of the trailing edge. The conduits are separated by a distance. A first cable having a first length extends within the first conduit and a second cable having a second length extends within the second conduit, and the fairing can rotate about the first cable within the first conduit.

Embodiments relate generally to marine geophysical surveying. More particularly, embodiments relate to an underwater application system for application of a streamer coating to a surface of a streamer. An embodiment may comprise a marine geophysical survey system. The marine geophysical survey system may comprise a streamer and an underwater application system operable to apply a streamer coating to the streamer as the underwater application system travels axially along the streamer.

An in-line planer board assembly incorporates hydrofoil designs at various key locations in order to maximize fluid movement efficiencies. Optionally, the planer board assembly further includes a spring-loaded fishing line release, also exemplified in a universal embodiment for use with other planer boards. Another option is a snap-in forward line release bracket useful when an angler wishes to fish from the opposite side of the boat, or for creating a smaller storage space requirement while storing the planer boards away between angling trips.

A sandwich cable fairing designed for attachment to cables that are towed at operational speeds by marine vessels. The sandwich cable fairing has a seven-layer design that combines layers of elastic, fiber reinforced, and adhesive materials. The fairing dampens the vibration resulting from the frequency of flapping caused by a cable being towed at operational speeds. The layering of materials allows the fairing to have the flexibility to be crushed by cable equipment while maintaining the requisite stiffness to reducing flapping and the resulting vibration.

There is provided a spreading device (100) for trawl fishing and seismic survey operations. The device has an upper frame (111), an intermediate frame (113) and a lower frame (112). There are at least two upper panels (22, 23) between the upper and intermediate frames, and at least two lower panels (22, 23) between the intermediate and lower frames. One of the upper panels and one of the lower panels adjustable in its angle of attack with respect to other panels. There is provided a manual means for adjusting the angle of attack of the adjustable panels.