An attitude-adaptive hydrofoil apparatus, including: strut-braced wing assemblies, a horizontal wing assembly, connection plates, and attack angle adjusting plates. The strut-braced wing assemblies each include a bearing, at least one inclined tube, at least one inclined flow-guiding wing, and at least one stop dog. The horizontal wing assembly includes a horizontal tube, at least one horizontal flow-guiding wing, and at least one depth-locating wing. The attack angle adjusting plates each include an angle adjusting end plate having a hole. The strut-braced wing assemblies are symmetrically disposed at two sides of the horizontal wing assembly. The bearing is fixed on a vessel body by welding. The at least one inclined flow-guiding wing is sleeved on the at least one inclined tube, and is limited by the at least one stop dog. The attack angle adjusting plates are disposed at two ends of the horizontal tube, respectively.

A marine seismic surveying apparatus for obstructed waters includes a deployed device and a buoy. The deployed device is disposed at an end of a streamer and is towed below a surface of water. The buoy extends from the end of the streamer to the water's surface. A coupling connects the buoy to the end of the streamer and is breakable due to tension from the buoy obstructed at the surface of the water. A receiver associated with the buoy obtains location information via the buoy at the water's surface. The deployed device can reckon its location with an inertial navigation system in place of location information obtained with the buoy's receiver. Also, the buoy can be deployed at the surface of the water, and more than one buoy can be available for deployment should one be lost.

The invention relates to a seismic streamer (1) for underwater towing at a towing speed in ice-free or wholly or partially icy water, the streamer (1) is provided with birds (2) spaced along the streamer, the streamer including the birds (2) has negative buoyancy, the birds have wings (8) which can be set so that the birds during movement in the water apply an upward or downward force on the streamer. The streamer (1) is provided with buoyant bodies (4) spaced along the streamer, the buoyant bodies are connected to the streamer by spacer elements (5), the streamer including the birds, the buoyant bodies with associated spacer elements and any other equipment together have positive buoyancy. The invention also relates to a corresponding method for securing a seismic streamer (1) from damage at a substantial reduction or cessation of towing speed when towing underwater in ice-free or wholly or partially icy water.

A variable drag area tow system including a tow cable, and a variable drag area device having a variable projected area, the variable drag area device is configured to have a smaller projected area as the velocity of the variable drag area device with respect to a fluid increases. A method of maintaining tension on a tow cable, the method including deploying at a first velocity a variable drag area device having a variable projected area, increasing the first velocity to a second velocity, and decreasing the projected area of the variable drag area device as the first velocity is increased to the second velocity.

A fairing for suppressing a vortex induced vibration (VIV) of a tubular. The fairing including a tail member dimensioned to suppress a vortex induced vibration of a tubular. The fairing further including an encircling member dimensioned to encircle less than an entire circumference of a tubular, the encircling member being separable from the tail member. The fairing further including a connecting assembly dimensioned to attach the tail member to the encircling member.

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.

An underwater device intended to be towed by a surface ship, the surface ship being capable of including a handling system for stowing and deploying the underwater device. The handling system includes a tow cable and an attachment cable. The underwater device includes a flexible elongate body and a towed body, the towed body being capable of being arranged between the tow cable and the flexible elongate body. The underwater device also includes an intermediate element capable of being arranged between the towed body and the flexible elongate body. The intermediate element is connected to the towed body by a first connection. The intermediate element is connected to the flexible elongate body by a second connection, the first connection being an articulated mechanical connection. The intermediate element is a cable of low stiffness. The underwater device includes a recovery cord.

Example embodiments provide a reinforced fairing apparatus and method for hydrodynamic drag and vibration reduction. Example embodiments provide a reinforced fairing apparatus comprising a tow cable, a plurality of ribbons, and a plurality of stiffening elements. According to example embodiments, the tow cable may comprise strands of a metal arranged into at least one line and configured to be attached at each end. The plurality of ribbons may extend from at least part of the tow cable. Each ribbon may have at least one of the stiffening elements in a configuration throughout the length of the ribbon. The plurality of ribbons, aided by the stiffening elements, may be configured to be pliable during storage and streamlined with fluid flow during use. The plurality of stiffening elements may be a plurality of midribs.