272results about "Ship vibration reduction" patented technology

An elongated, annular hull of a floating offshore platform includes one or more segmented, helical strakes disposed on an outer peripheral surface of the hull to reduce vortex-induced vibrations resulting from water currents. The hull may comprise a single annular hull or a plurality of parallel, adjacent hulls. Each strake includes a plurality of generally rectangular segments extending substantially radially outward from the hull. Each of the segments includes a pair of spaced-apart radial stanchions supporting a generally rectangular frame to which a corresponding panel is attached. The panels have a radial width that is about 13 percent of the effective diameter of the hull. The segments are arranged in a spaced-apart, end-to-end relationship that defines a discontinuous, but generally helical band extending around the circumference of the hull from about 35 feet (11.7 m) below the mean water line of the hull to its lowermost end.

A system is disclosed for dynamically stabilizing a ship in high sea states. A six degree-of-freedom robotic arm is attached to the ship, and a thruster is located at the distal end of the manipulator. The manipulator is be used to orient the thruster to counteract wave forces that act against the ship's hull in real time. This active balancing technique can be used to keep the ship substantially erect in rough seas by making continual corrections to the ship's body attitude. The center of gravity and the center of buoyancy of the ship are utilized, along with a precisely oriented and controlled thrust at the end of the manipulator, to optimally control the ship's state against impending waves.

A water craft (77) is disclosed which includes a chassis portion (78), at least four water engaging means (30, 34, 38, 42) and interconnecting means (94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132). Each water engaging means is connected to the chassis portion (78) and is moveable in a substantially vertical direction relative to the chassis portion (78), and the interconnection means is arranged to functionally link the at least four water engaging means (30, 34, 38, 42) such that during use the chassis portion is encouraged to maintain an orientation which is substantially constant relative to the average plane of the water surface, even when the water surface is undulating and the water engaging means (30, 34, 38, 42) are not all disposed in the same plane.

The present invention provides methods and apparatus for reducing sinkage and wetted surface, and thus hydrodynamic drag of a high-speed boat through the generation of aerodynamic lift while decreasing overall aerodynamic drag. At least one lift-generating front wing proximate a bow section of the boat with at least one corresponding front air channel may be provided. At least one lift-generating rear wing proximate a transom section of the boat with at least one corresponding rear air channel may also be provided. At least one of the wings may be adjustable to generate aerodynamic lift with one of: (1) a neutral; (2) a transom-lifting; and (3) a bow-lifting pitching moment about a center of inertia of the boat. At least one wing proximate the leading edge of the tunnel of a multi-hull boat may be provided to increase the operational envelope.

The invention discloses a wind and wave resisting floating type offshore photovoltaic power generation platform. A platform truss, a photovoltaic plate assembly, weight balls, support columns, a floater, a heaving plate, pile foundations and mooring cables are included. The photovoltaic plate assembly is flatly laid on the platform truss. The weight balls are arranged below the platform truss. Thesupport columns are connected with the platform truss and the weight balls. The floater is fixed between the support columns, and buoyancy provided by the floater can be transmitted to the photovoltaic power generation platform. The heaving plate is connected to the lower portions of the weight balls. The pile foundations are fixed in a seabed and used for mooring the offshore photovoltaic powergeneration platform. One ends of the mooring cables are moored to the support columns, and the other ends of the mooring cables are moored to the pile foundations. By means of the wind and wave resisting floating type offshore photovoltaic power generation platform, the capability of resisting wind, waves and flow loads through a supporting structure is guaranteed, economic feasibility and construction convenience are achieved, and accordingly application of the photovoltaic power generation platform to the field of ocean open water area is assisted.

A water craft has a body portion and at least two water engaging means. The body portion is at least partially suspended above the at least two water engaging means by a suspension system, and locating means are provided to connect each water engaging means to the body portion to permit substantially vertical and pitch direction motions of the water engaging means relative to the body. The suspension system includes at least one front pitch support ram and at least one back pitch support ram, the front and back pitch support rams providing support for at least a portion of the body relative to the at least two water engaging means.

The invention discloses a six-degree-of-freedom wave compensation platform, and belongs to the field of wave compensation equipment. The six-degree-of-freedom wave compensation platform comprises a base plate, a 2R1T parallel compensation unit, a 1R2T serial compensation unit, and an upper platform. The base plate is mounted on a ship deck; the 2R1T parallel compensation unit is mounted on the base plate; the 1R2T serial compensation unit is mounted on the 2R1T parallel compensation unit; and the upper platform is mounted on the 1R2T serial compensation unit. The six-degree-of-freedom wave compensation platform can compensate six-degree-of-freedom motions of heaving, yawing, rolling, surging, pitching and swaying of a ship under the wave effect. The six-degree-of-freedom wave compensationplatform is simple in structure, high in bearing capacity, convenient to control and high in pose control precision.

The invention relates to a rotatable fairing (1) for a marine riser (2) or other slender marine structure. The fairing (1) is arranged on the riser for reducing watercurrent-induced stresses on said riser (2), said fairing (1) having a tail portion (3) for trailing generally in the downstream direction behind said riser. The fairing (1) is provided with an attenuation unit (8) for counteracting the unstable rotation of said fairing (2) relative to said riser (2), in order to prevent undesired vibrations of said riser (2). The fairing is provided with one or more clamps (10) for attachment to and around a periphery of said riser (2), said clamps (10) arranged with a gear rim (12) for engagement with an actuating cogged wheel (14) of said attenuation unit (8).

In an Extendable Draft Platform including a deck, a plurality of buoyancy columns installed in column wells in the deck for movement from a raised position to a submerged position, and a heave plate on the bottom of the columns, each of the columns has an upper portion and a lower portion. A helical strake having a radial height H is fixed to the lower portion of each column. The maximum width of the lower column portion is less than the maximum width of the upper column portion by at least 2H, so that the strake can pass through a column well having maximum width that is only slightly greater than that of the upper column portion. A plurality of guide rails is fixed to the lower portion of each column, each extending along the outer periphery of the strake from the upper column portion to the heave plate.

An active suspension system is used to control the motion of a passenger seat in a high speed watercraft. A forward looking wave sensor is used in connection with a feed-forward wave impact shock predictor to determine characteristics of impending dynamic forces applied via the impact of the watercraft on waves. Information concerning the impending dynamic forces is used by a passenger seat suspension and control system to attenuate the shock effects on passengers, where such effects are characterized by large-amplitude, short-duration accelerations recurring at a low frequency and / or irregularly.