273results 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 modular marine vessel has a variable hull and a plurality of boat forming modules including a bow section module, a load section module having a bow end and an aft end, and a bulkhead forming module is detachably connected to each bow and aft end of the load section module. The bulkhead forming module that is connected at the bow end of the load section module is detachably connected to the bow section module. Each boat forming and bulkhead forming module includes a topside section and a hull bottom side section. The topside section of each boat forming module has a shell gunnel portion, and the hull bottom side section of each boat forming module has a pivotally mounted bottom shell hull portion. The gunnel and hull portions of the load and bow section modules are detachably connected end-to-end, and sealingly juxtaposed the detachably connected bulkhead forming module to prevent water from entering the boat when the boat engages water. The bottom shell hull portion is pivotally mounted across a keel tunnel using a pneumatic, hydraulic, mechanical, or electro-mechanical actuator to form a preselected hull shape as desired. Novel mechanisms for sealing module connections, for module attachment, for pivoting hull panels, for hull pivot drives, and energy conversion systems for the marine vessel of the invention are disclosed.

Apparatus and methods for reducing vortex induced vibration are provided. An apparatus for reducing vortex induced vibration can include a first body at least partially disposed within a second body. The first body can be made of a material having more weight per linear foot than the second body. The apparatus can also include one or more helical fins.

Methods and apparatus for the installation of VIV suppression during the S-Lay installation of a subsea pipeline. A locking member will be interposed between a pipe and a fairing rotatably mounted on the pipe, sufficient to bias the fairing against rotating. Upon marine application, the locking member will degrade, thereby releasing the fairing.

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 wave compensation measuring device, a measuring method and an applicationthereof in an ocean platform. The wave compensation measuring device comprises acompensation drive unit and a platform displacement measurement unit, the compensation drive unit comprises a rolling compensation drive device, a pitch compensation drive device, a heave compensation drive device and a drive connection rod; the connection between an upper measurement plate and a lower measurement plate is connected with six linear displacement sensors. The platform displacement measurement unit is arranged to simulatethe six degrees of freedom platform, whereinthe six linear displacement sensors correspond to the six servo cylinders of the six degrees of freedom platform; a compensation drive unit is arranged so as to conductwave compensations on theplatform displacement measurement unit, thus the wave compensation volume of theservo cylinders of the six degrees of freedom platform six is measured, the complex parallel connection machine program algorithm is converted into a mechanical news transmission mechanism, and the wave compensation measurement difficulty is reduced.

Systems and methods for remotely installing a clamshell device around an element, the clamp system comprising a body; and at least one set of clamps supported by the body, the set suitable for holding and releasing the clamshell device selected from the group consisting of vortex-induced vibration reduction devices and drag reduction devices, wherein at least one clamp comprises a cam surface adapted to engage the element and close the clamp about the element.

Methods and systems for controlling processes related to the amount of fluid in a container subjected to externally-excited motions. Fluid level sensor measurements in processing tanks on-board boats are confused by ocean waves and swells. A hydrodynamic model of a fluid in a tank can be constructed using non-linear dynamic model algorithms with inputs such as multi-axis accelerations, fluid viscosity, and apparent level measurements. The model can be used to filter-out boat motion disturbances to obtain a corrected level of the fluid in the tank. The corrected fluid level signal can be further processed using a dynamic model of the tank and associated input and output flow rates in a closed loop observer. The methods and systems are especially advantageous for offshore equipment such as cementing and fracturing ships.

An offshore well platform is towed in an upright condition to a well site by the use of a temporary flotation device. The flotation device mounts to a portion of the platform and is partially submerged, increasing the ability and buoyancy of the platform. At the site, the engagement of the flotation device shifts to a deploying position. In the deploying position, the ballast of the platform is increased to cause it to more deeply submerge. The flotation device remains at least partially surrounding the platform and floating while the platform moves downwardly relative to it. This provides lateral support if needed to prevent heeling while being submerged. The flotation device is disengageable from the platform when the platform is fully submerged.

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).

Thrusters in communication with a feedback control system are provided on a cylindrical offshore marine member, such as a spar, for reducing and / or controlling vortex-induced-vibrations, low-frequency drift oscillations due to random waves, and low-frequency wind induced resonant oscillations. The thrusters are provided thrust instruction from the feedback control system based on marine member displacement and current velocity.

A cushioning apparatus provides an improved on a watercraft in order to improve the comfort of the ride, to reduce rider fatigue and to cushion impact forces experienced by the watercraft hull. The cushioning apparatus absorbs at least a portion of any impact force which the rider experienced from the hull, as well as provides a degree of movement between the rider and the hull in order to cushion such impact forces. The cushioning apparatus may also isolate the rider, at least to some degree, from vibrations experienced by the hull.

An improved cushioning apparatus on a watercraft enhances the comfort of the ride, reduce rider fatigue, and cushion impact forces experienced by the watercraft hull, while allowing for convenient and easy access to various engine components for maintenance and repair of the engine. The cushioning apparatus absorbs at least a portion of any impact force which the rider experienced from the hull, as well as provides at least one degree of movement between the seated rider and the hull in order to cushion such impact forces. The cushioning apparatus may also isolate the rider, at least to some degree, from vibrations experienced by the hull. In one mode, the cushioning apparatus is connected to the watercraft by quick-disconnect fittings, which allow the seat and support frame to be easily moved away from an engine access opening for maintenance of the engine. Furthermore, a quick-access opening is disclosed which allows a rider to access various engine components without requiring that the cushioning apparatus be disconnected from the watercraft. Moreover, the cushioning apparatus increases the convenience and stability of the watercraft for heavier load conditions such as when multiple riders are riding on the watercraft.

A marine buoy for the offshore support of subsea production and drilling activities that has a closed-bottomed base section with a solid ballast and variable ballast chambers, a chamber in the base section for storing equipment and supplies, and an upper section with a smaller cross-sectional area than the base section having an elevator shaft leading from the top of the upper section to the chamber in the base section. The upper section supports a deck for housing process equipment for operations that the marine buoy is supporting.

A suppression element (1) for vortex vibrations, comprising an envelope (2) for t least partly enveloping a tubular element (100); at least one projection (3) pointing away from the envelope. The envelope is modular to form with similar suppression elements a tube (101,102), which, in operation, at least partly, envelops a tubular element (100). Also, a construction kit for a suppression system and a suppression system for vortex vibrations with at least two suppression element (1), which together form a tube, which in operation, at least partly envelops a tubular element (100), as well as an apparatus for extracting minerals with a pipeline enveloped by a suppression system are disclosed.

A watercraft has a pivoting, shock absorbing component that absorbs forces applied to its hull. The watercraft includes a hull, a deck coupled to the hull, an engine, and a jet propulsion system movably coupled to the engine. In one embodiment, a forward hull portion couples to the deck and a rearward hull portion movably couples to the deck and / or the forward hull portion. The jet propulsion system mounts to the rearward hull portion, while the engine mounts to the deck. A suspension element is disposed between the hull rear portion and either the deck or the hull forward portion. In another embodiment, the hull and deck are movably coupled to each other.

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 substantially cylindrical buoyancy module for a marine riser includes a plurality of buoyancy elements separated along at least one helical separation plane.

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).

The invention relates to a heavy-draft truss upright-column combined platform which is characterized by comprising a regular-polygon or subregular-polygon annular ballast compartment, a plurality of vertical upright columns, a drilling machine and an oil gas processing module, wherein the vertical upright columns are positioned at the angular points of the annular ballast compartment, and the drilling machine is positioned on the top of the upright columns; the annular ballast compartment adopts a permanent ballast mode, and a weight is filled in the compartment, thereby ensuring that the center of buoyancy of the platform is higher than the center of gravity of the platform; the lower parts of upright columns are connected with the annular ballast compartment to form an integral body, the upper part of each upright column is in a cylinder or subterete shell structure, the lower part of the upright columns adopts a truss structure, and the middle parts of every two adjacent upright columns are connected through a buoyancy tank structure which can provides sufficient buoyancy force for the platform; and each upright column is provided with a set of berthing ropes, and the berthing ropes are connected to benthonic anchor points in a traditional anchoring mode. The invention has the advantages of favorable moving performance, wide applicability for operating water depth, high strength of the monolithic construction, light weight and low construction cost, and can be used for deep water oil gas exploitation in severe marine environments.

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.

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.

A semisubmersible platform includes a deck supported on the upper ends of support columns extending upwardly from a horizontally disposed pontoon-ring. The columns are battered inwardly and upwardly from the pontoon-ring to the deck. Mooring lines passing through fair leads on the outer faces of the base nodes anchor the platform to the seabed. The footprint of the battered columns is greater than the footprint of the deck supported on the upper ends of the columns.

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.

The invention relates to an electric ocean wave active compensation embarkation system and a control method thereof, and relates to the technical field of marine engineering. The system comprises a rolling compensation mechanism, a pitching compensation mechanism, a stretching and retracting compensation mechanism, a pose detecting system, a movement control system and an electrical system. The method comprises the following steps: connecting a base with a deck of a ship; placing the tail end of the system on a marine fan platform, wherein the pose and position of the ship can be changed due to the fact that the ship is affected by ocean waves; detecting the ship change position and a posture change parameter by using the pose detecting system; providing control information feedback to the movement control system; and controlling the rolling compensation mechanism, the pitching compensation mechanism and the stretching and retracting compensation mechanism to actively compensate the ocean waves in real time by using the movement control system according to parameters of the pose detecting system through model resolving and motion control calculation. The ocean waves are actively compensated, and therefore, maintenance staffs can safely and reliably walk on the marine fan platform.

A floating offshore wind turbine comprises a rotor with a plurality of blades, a nacelle and a nacelle support structure having a central longitudinal axis. A plurality of tuned mass damping configurations is arranged around the central longitudinal axis of the nacelle support structure to dampen vibrations in all 6 degrees of freedom.