A subsea carrier (100) for transporting a fluid, e.g. CNG or crude, comprises a main body (101) for containing the fluid at a predetermined internal pressure, wherein the main body (101) preferably is made of concrete and designed to operate at a water depth where the external pressure substantially counteracts the internal pressure. The subsea carrier has a floating element (102) connected to the main body (101) by a stabilising cable (132), wherein the stabilising cable (132) comprises a first rope (321) for transmitting force and is attached to a first connector (134) that is movable with respect to the main body (101). A system wherein the subsea carrier is towed by a surface vessel (3) or is self-propelled and controlled remotely is also disclosed. The subsea carrier (100) reduces operational costs relative to subsea carriers with traditional control surfaces and ballasting systems at large cargo volumes, e.g. 150 000 m.sup.3 or more.

A seabed object detection system is provided. The system can include a receiver array including streamers. The system can include a plurality of receivers coupled with the streamers. The system can include a receiver array cross-cable to couple with the first streamer and to couple with the second streamer. The receiver array cross-cable can be disposed at a first depth of a body of water. The system can include a first diverter and a second diverter coupled with the receiver array cross-cable. The system can include a source array including a first source and a second source. The source array can be coplanar to the receiver array. The system can include a source array cross-cable to couple with the first source and to couple with the second source, the source array cross-cable disposed at a second depth of the body of water.

A method of manufacturing marine riser buoyancy elements includes providing a master mold and mold inserts such that a range of buoyancy elements may be manufactured from one master mold and providing the mold inserts such that an annular space between the riser main conduit and the buoyancy elements, or a groove width between the buoyancy elements may be varied during manufacture.

A cable fairing (fairing) (40) for reducing the flow resistance for a cable (45) has a wing formed cross section with a wide, rounded front and a tapered tail, a through-going cable channel (46) for the cable (45) perpendicular to the cross section of the widest part of the cross section. The wing profile comprises an elastic material of sufficient stiffness to maintain the shape when it is towed thereby causing flow resistance. The cable fairing (40) has slots (42) cut into the elastic material from the tail towards the cable channel (46), so that the tail comprises slats (41) which can be bent parallel to the cable channel (46) to reduce the cross-section of the cable fairing. By this is low flow resistance, as from a stiff cable jacket, combined with sufficient elastic deformability so the cable (45) with attached cable fairings (40), can be winched and pass through narrow openings in the deployment and retrieval, and wound onto a reel for storage and transport.

An apparatus. The apparatus includes a body and a plurality of control surfaces attached to the body. A first control surface is configured to control an ascent and descent of the apparatus, responsive to ascent/descent control information. A second control surface is configured to control a roll of the apparatus responsive to roll control information, and a third control surface is configured to control a yaw of the apparatus responsive to yaw control information. The apparatus further includes a releasable first docking fixture attached to the body, the first docking fixture configured to engage a second docking fixture on a payload.

A segmented-foil divertor for marine towed application, such as marine seismic exploration, having a plurality of longitudinally stackable foil segments with an internal conduit extending along the span of each segment to receive a cable passing therethrough.

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 ribbon-foil depressor is incorporated into a towed seismic array to provide downward lift to array sections or components. The ribbon-foil depressors may be deployed on the port and starboard spur lines or on the outboard separation ropes. The ribbon-foil depressors may be used to submerge and operate seismic equipment at depths as low as 60 m or more and are capable of maintaining towed seismic streamer cables at these depths and still remain stable through various speed changes and turns.

An apparatus for acquiring survey data including streamer equipment comprising a lead-in cable; and a geophysical streamer with a plurality of geophysical sensors distributed along the geophysical streamer, including a forward geophysical sensor; a depressor coupled to the streamer equipment in front of the forward geophysical sensor; a variable tension control device coupled at a back end of the geophysical streamer; and a plurality of tension control system sensors. A method for acquiring survey data including obtaining data from tension control system sensors of a geophysical streamer system; identifying an adjustment to be made to one or more tension control factors of the geophysical streamer system to reduce or control vibrational behavior of streamer equipment of the geophysical streamer system making the adjustment to the one or more tension control factors; and acquiring survey data with the geophysical streamer system.

Apparatus and techniques are disclosed relating to towing marine equipment. In some embodiments, a vessel tows equipment through a body of water using a towing member with an associated fairing that includes a slit, such that an axis of the slit is non-perpendicular to a portion of the towing member from which the fairing extends.