70results about "Ship vibration reduction" patented technology

A marine eight-degree-of-freedom anti-swing gallery bridge stabilizing system comprises an anti-swing lifting system and a telescopic gallery bridge device arranged on the upper portion of the anti-swing lifting system. The anti-swing lifting device is fixedly connected with a deck of a ship body through a base, and the anti-swing lifting system is composed of a horizontal left-right rotating device arranged on the upper plane of the base, a transverse anti-swing longitudinal anti-swing device arranged on the upper portion of the horizontal left-right rotating device, and a longitudinal anti-swing device arranged on the lower portion of the base. The lifting devices are arranged on the left side and the right side of the transverse anti-swinging and longitudinal anti-swinging device and on the bottom base; the telescopic gallery bridge device is erected on a rolling platform at the upper part of a transverse anti-swinging device and a longitudinal anti-swinging device which are arranged between the left frame and the right frame of the lifting device in a stacked manner; the whole telescopic gallery bridge device can swing left and right, transverse and longitudinal state adjustment can be achieved under the action of the transverse anti-swing and longitudinal anti-swing device, and eight-degree-of-freedom regulation and control of the whole telescopic gallery bridge device can be achieved under the action of the lifting device.

The invention belongs to the technical field of ship equipment, and discloses a wave suppression device and a ship. The wave suppression device comprises a hinge four-bar mechanism, a spoiler sheet and a rotary driving part, and the rotary driving part drives the spoiler sheet to rotate through the hinge four-bar mechanism, so that the spoiler sheet has a working position extending into water. The rotary driving part is arranged above the water surface, and the sealing surface of the rotary driving part is separated from the seawater environment, so that the possibility that marine organisms are attached to the sealing surface of the rotary driving part is fundamentally avoided, and the maintenance frequency and the environmental protection risk are remarkably reduced. Besides, the rotary driving part is far away from a seawater corrosion environment and does not need to bear underwater pressure, so that the failure probability of the sealing part caused by seawater corrosion or mechanical shock is reduced, the working stability of the driving system is improved, and the service life of the driving system is prolonged.

Methods and systems are provided for nautical stationkeeping of free-floating objects. In one example, a method includes adjusting translational motion of a body freely floating in water by rotating the body. The translational motion may be adjusted, for instance, to maintain the body within a geographic area. In certain examples, the adjustment of the translational motion may be realized via a Magnus effect induced by rotating the body. The body may be configured as, for example, a free-floating object such as a wave engine.

The present invention discloses a floating wind turbine foundation and wind turbine equipment. The floating wind turbine foundation includes at least one floating body unit, which includes an annular floating body and a sway reduction plate assembly. The sway reduction plate assembly includes at least two sway reduction plates arranged vertically. The sway reduction plates are provided with a plurality of first flow-disrupting holes. The first flow-disrupting holes penetrate the sway reduction plates along their thickness. The first flow-disrupting holes of two adjacent sway reduction plates are vertically staggered. The topmost sway reduction plate is connected to the annular floating body. The upper surface of the topmost sway reduction plate and the inner peripheral wall of the annular floating body enclose a receiving groove. The present invention can effectively reduce the shaking and heaving amplitude of the wind turbine foundation, improve the stability of the wind turbine foundation, and improve the anti-overturning effect.

This invention discloses a semi-submersible offshore platform with movable wave-breaking plates, belonging to the field of floating wind turbine turbulence. It comprises multiple platform components connected by trusses. Each platform component includes a column with a vertically oriented axis. Several movable wave-breaking plates are provided on the outer wall of the column, spirally distributed around the column's axis. Each movable wave-breaking plate includes an anti-roll plate fixed to the column's peripheral wall. A hinge is located at the lower end of the anti-roll plate; one side of the hinge is fixedly connected to the anti-roll plate, and the other side is connected to an arc-shaped cover plate. The hinge's rotation axis is horizontally oriented. The side of the arc-shaped cover plate facing the column's outer wall bulges upwards, allowing it to rotate around the hinge's axis under buoyancy. This invention can reduce vortex-induced motion and decrease platform oscillation.

The invention relates to a heaving plate with adjustable damping, a floating platform and a control method thereof.The heaving plate comprises a plate body, a water passing adjusting hole penetrating through the upper end face and the lower end face of the plate body is formed in the plate body, the heaving plate further comprises an opening and closing adjusting device installed on the plate body, and the opening and closing adjusting device comprises a plugging piece and a driving mechanism; the blocking piece is used for blocking or opening the water passing adjusting open hole, and the driving mechanism is connected with the blocking piece and can drive the blocking piece to move and adjust the opening and closing degree of the water passing adjusting open hole. The heaving plate is arranged in the floating platform, the damping effect of the heaving plate can be adjusted according to actual needs, use is flexible, and the stability and use flexibility of the floating platform can be ensured.

The invention discloses an image recognition intelligent sensing type full-cavity magneto-rheological floating fan stabilization system and method. The system comprises an environment intelligent sensing module, a digital twinning module, a full-cavity magneto-rheological execution module and a central control module. The environment intelligent sensing module collects a wave image in real time and outputs a sea wave period; the digital twin module reconstructs a six-degree-of-freedom motion state of the variable floating type fan platform and a three-dimensional scene view of surrounding sea waves; the full-cavity magneto-rheological execution module moves and excites according to the sea wave period, the acting area and intensity of a magnetic field are adjusted, the chaining degree of magneto-rheological fluid is changed, and damping stepless adjustment is achieved. The central control module generates a corresponding control instruction and sends the control instruction to the full-cavity magneto-rheological execution module; according to the method, digital and physical double reproduction of floating type fan platform motion and the sea wave environment is achieved, self-adaptive damping adjustment can be accurately and rapidly conducted on broadband sea waves, and the power generation efficiency and platform safety are remarkably improved.

The invention belongs to the technical field of semi-submerged platforms, and discloses a transverse supporting structure and a semi-submerged platform, the transverse supporting structure comprises two transverse supporting pieces which are arranged in the transverse direction of the semi-submerged platform and arranged in the longitudinal direction of the semi-submerged platform at intervals, and the two transverse supporting pieces are located between two stand columns of the bow or the stern of the semi-submerged platform; each transverse supporting piece is used for being connected with two stand columns of the bow portion or the stern portion of the semi-submersible platform. The heaving plate is arranged between the two transverse supporting pieces and connected with the two transverse supporting pieces, and first reinforcing ribs are arranged on the heaving plate. According to the cross arm structure, the heaving, rolling and pitching periods of the semi-submerged platform can be prolonged, resonance, equipment damage and the like caused by the fact that the inherent period of the semi-submerged platform is close to the wave period are avoided, the motion response of the semi-submerged platform is reduced, and the seakeeping performance of the semi-submerged platform is improved.

The invention discloses an offshore wind power platform and an offshore wind power system, and relates to the technical field of wind power generation. The supporting column is used for supporting the fan; the floating barrels are distributed around the supporting column at intervals, and the floating barrels are connected with the supporting column through connecting pieces; the damper is used for being connected with the bottom of the supporting column so as to restrain vertical displacement of the supporting column. According to the offshore wind power platform, vertical displacement of the supporting columns can be prevented and restrained through the dampers arranged at the bottoms of the supporting columns, so that the risk of fan shaking caused by sea waves is reduced, and compared with the mode that fan shaking is reduced through a water ballast space, the response speed is higher, and the stability of the offshore wind power platform is improved.

The present invention discloses a wave-breaking and current-reducing device suitable for offshore photovoltaic systems in port areas, comprising a frame structure, wherein a wave-breaking and current-reducing power generation device and a current-reducing power generation device are continuously installed along the length direction of the frame structure; the wave-breaking and current-reducing power generation device comprises a spring, a lifting plate, a first power generation system, a first mounting frame, and a slide rail; a limiting sleeve that slides with the slide rail is fixedly provided on the side end of the lifting plate, and a rack is fixedly connected to the limiting sleeve, and the rack can be inserted into the coil of the first power generation system during movement; the current-reducing power generation device comprises a vibrator, a spring limiting layer, and a second power generation system; a rack is fixedly connected to one end of the vibrator corresponding to the second power generation system, and the rack can be inserted into the coil of the second power generation system during movement. The present invention aims to provide a wave-breaking and current-reducing device that can effectively reduce the impact of waves and tidal currents on photovoltaic platforms, and can also utilize wave energy and tidal current energy to generate electricity, thereby achieving dual utilization.

The invention discloses a flexible breakwater system which is located in a ship stern cabin and arranged in a bilateral symmetry mode and comprises a breakwater, a charging and discharging mechanism, a retracting and releasing mechanism used for conveying the breakwater, an anchoring mechanism used for connecting the breakwater with a ship and recycling the breakwater and a control system. The breakwater is a bag body capable of being filled with gas and liquid; the folding and unfolding mechanism comprises a conveying guide rail for transporting the breakwater; the control system responds to a pressure signal of the breakwater and synchronously adjusts the medium flow of the filling and discharging mechanism, the dip angle and speed of the conveying guide rail and the tension of the anchoring mechanism. Compact folding of a ship-borne space is achieved through an air bag and water bag structure connected through a hinge, a synchronous operation chain of bag body filling and discharging, sliding into water and triangular anchoring is formed by combining an inclination angle adjustable guide rail and a pressure feedback cooperative control system, rapid laying and accurate positioning of the breakwater under the high sea condition are achieved, the wave absorbing efficiency of a ship stern operation area is improved, and the wave absorbing effect of the ship stern operation area is improved. And the task success rate and the operation safety of the amphibious ship under the severe sea condition are obviously improved.

The invention relates to various methods and systems for controlling the inclination of a rocking structure. One method concerns adjusting a force applied by an electric machine to a mass coupled to the rocking structure. The method is based on executing a control that uses a dynamic model and indicative parameters of the position of the mass and of an angle of inclination of the rocking structure to adjust the force applied by the electric machine to the mass. The invention also relates to a system for carrying out the method. Another method relates to adjusting the transmission ratio between a mass coupled to the structure and a rotor of an electric machine. A further method relates to adjusting the curvature of a guide for mechanically coupling a body to the rocking structure.

The invention discloses an FLNG-LNGC combined loading and unloading operation control method and system based on real-time working condition feedback, and the method comprises the steps: firstly constructing a system state space with time-space synchronization, and collecting the time calendar of a wave field and the motion response of a ship body; and reconstructing an instantaneous wave energy spectrum, resolving ship body modal parameters, and calculating a frequency detuning safety factor. When the resonance risk exists, the system executes asymmetric loading path planning based on frequency detuning optimization, and the rotational inertia of the ship body is changed by adjusting cabin flow distribution so as to shift the inherent frequency; and meanwhile, a gas-liquid coupling active suppression instruction containing variable stiffness pressure modulation and pulse momentum damping is generated, the recovery stiffness is changed through gas phase pressure, and damping torque is generated through fluid momentum. And finally, the instructions are synthesized to drive an execution mechanism. Active regulation and control of ship body modal frequency and instant dissipation of wave disturbance are achieved, the resonance risk is effectively reduced, and the stability of double-ship operation under the severe sea condition is improved.

The invention relates to a system (2) for forming an anchoring point for a floating body of an offshore wind turbine, comprising at least one capsule (6) having an open bottom (8) and an open top (10), which capsule is at least partially filled with a solid particulate material (12) capable of withstanding shear forces with the seabed (4) on which the capsule is intended to sit, the capsule further comprises at least one attachment (14) for securing a mooring line (16) of the floating body.

The application provides a water photovoltaic system and an arrangement method thereof, which comprises a ring-shaped wave-preventing slope, a plurality of integrated fan-shaped floating plates are arranged in an array along the axis of the ring-shaped wave-preventing slope, the same connecting disc is fixedly connected to the ends of the plurality of integrated fan-shaped floating plates away from the ring-shaped wave-preventing slope, the fixed seat and the piston float are abutted through extrusion springs, the piston float is provided with a one-way air inlet valve for pumping water into the buffer groove from the outside, and the blocking net is retracted in the blocking net groove arranged in the upper portion of the ring-shaped wave-preventing slope. The ring-shaped wave-preventing slope is arranged around the floating photovoltaic device, which can effectively weaken the large fluctuation of the photovoltaic floating plate caused by the fluctuation of the water surface in each direction, and can also absorb the large fluctuation of the internal water surface through the lifting of the piston float, convert the energy generated by the water surface into the kinetic energy of the lifting of the blocking net, further prevent the photovoltaic assembly in the internal from being washed away under extremely complex conditions, and effectively ensure the safety of the water floating photovoltaic assembly.

The invention provides an active yaw adjusting system and method for a floating platform, the active yaw adjusting system comprises a monitoring unit, an anchor cable control system and three anchoring units, the three anchoring units are installed on three linear type buoys of the floating platform respectively, each anchoring unit comprises a linear guide rail, a movable anchor gear and an anchor cable, the linear guide rail extends in the length direction of the linear buoy, the movable anchor gear can move along the linear guide rail and can be locked on the linear guide rail, one end of the anchor cable is installed on the movable anchor gear, the other end of the anchor cable is provided with an anchoring part arranged on the water bottom face, and the movable anchor gear can take back or pay off the anchor cable. The included angle between the linear guide rails of every two adjacent anchoring units is 60 degrees. The control system is in control connection with the movable anchor machines of the three anchoring units; the monitoring unit is in communication connection with the control system and comprises a wave monitoring mechanism used for obtaining the period and direction of waves and a platform angle detection mechanism used for monitoring the direction of the floating platform.

A suspension system for a vessel (1) is disclosed, the vessel having at least one port hull (11), at least one starboard hull (12), and a underframe portion (10). The suspension system includes: supports (20) for at least partially supporting the underframe portion relative to the port and starboard hulls; and a left front damping plunger and a left rear damping plunger (31, 33) connected between the underframe portion and longitudinally spaced points on the at least one port hull, and a right front damping plunger and a right rear damping plunger (32, 34) connected between the underframe portion and longitudinally spaced points on the at least one starboard hull. The suspension system further includes a deck attitude control system (250) comprising a controller (252) for each of at least two orthogonally spaced damper plungers, sensors, and corresponding actuator devices. These actuators control the position of at least one point on the underframe relative to at least one reference.

The invention discloses a combined floating type offshore photovoltaic mooring structure, and relates to the technical field of offshore photovoltaic power generation, the combined floating type offshore photovoltaic mooring structure comprises a plurality of floating bodies, the floating bodies are assembled into an annular floating platform through connecting pieces, the side face of the annular floating platform is movably connected with a cable through a V-shaped connecting structure, and the end, away from the floating bodies, of the cable is connected with an anchoring seat; bearing hooks are arranged on the side wall of the floating body in a circumferential array mode, hoops are arranged on the bearing hooks in a penetrating mode, and the hoops are movably connected with the V-shaped connecting structures. The photovoltaic platform and the anchoring base are connected through the elastic cables, dynamic loads caused by waves, ocean currents and strong wind can be effectively coped with, and the service life of the photovoltaic platform is prolonged. The problem of structural damage caused by stress concentration in a traditional fixing mode is avoided, the stability and reliability of the photovoltaic platform structure under the severe sea condition are greatly improved, meanwhile, compared with a traditional structure, the connecting and fixing mode is simpler and more convenient to install and maintain, and the construction and operation cost of an offshore floating type photovoltaic project can be remarkably reduced.

The invention discloses a wind-wave-fish high-stability integrated system which comprises a floating fan platform, a heaving type wave energy power generation device and an ocean fishing net. The heaving type wave energy power generation device is installed in the center of a buoy of the floating type draught fan platform, captures energy through the vertical oscillation motion of the floating type draught fan platform under the action of waves and converts the energy into electric energy. And the ocean fishing net is fixed on the floating fan platform base. According to the floating fan platform, deep and far sea aquaculture can be achieved, and meanwhile the floating fan platform is further subjected to oscillation reduction and stabilization.

This invention proposes a floating photovoltaic platform, comprising a photovoltaic support platform, a flexible membrane, and several floats. The photovoltaic support platform includes buoys floating on the water surface and a deck positioned above the buoys. The buoys provide buoyancy, and the deck is used to mount photovoltaic modules. The floats are fixed around the photovoltaic support platform by mooring lines connected to the seabed and are spaced apart from the platform. The flexible membrane connects the deck and the floats, surrounding the photovoltaic support platform. This invention can buffer wave energy in advance using the flexible membrane, while simultaneously guiding water flow to cool the photovoltaic modules, thereby improving photovoltaic power generation efficiency.

The invention relates to the technical field of ocean, and particularly discloses a modular honeycomb floating body unit ocean platform structure and method.The modular honeycomb floating body unit ocean platform structure comprises a floating plate, wave-resistant units, connecting pieces, clamping and embedding blocks, connecting screw rods and fence columns, the wave-resistant units are fixedly connected with the floating plate and located at the lower end of the floating plate, and the two clamping and embedding blocks are arranged on the two sides of the connecting pieces correspondingly; the connecting piece is arranged on one side of the floating plate, one set of clamping and embedding blocks are embedded in the floating plate and detachably connected with the floating plate through connecting screw rods, the number of the fence columns is multiple, and each set of fence columns is in threaded connection with the floating plate and located at the upper end of the floating plate. The modularized structure is adopted for combination, transportation and installation are facilitated, meanwhile, when a single module breaks down, rapid maintenance and upgrading are facilitated, the required number of modules are correspondingly used according to requirements, the modules are flexibly installed and combined to form the required platform shape and structure, and the use and installation flexibility of the ocean platform is improved.

The present invention discloses a damping pendulum for preventing ships from capsizing. It is inevitable that ships will encounter strong winds and waves when sailing at sea. At this time, ships are most likely to shake violently or even capsize. This invention is to design and install a damping pendulum on the bottom of the ship to enhance the stability of the ship and greatly reduce the tilt angle of its left and right swing. This invention is to extend a damping pendulum like a large fan from the bottom of the ship and hang it on the bottom of the ship. Its two sides are obliquely pulled by anchor chains. When the hull swings left and right, the resistance of the water to the damping pendulum prevents the hull from swinging significantly, let alone capsizing. The entire operation process of the damping pendulum is carried out by a windlass pulling the anchor chain, which is simple and reliable to operate. In normal times, when there are no strong winds and waves, the damping pendulum can be retracted to fit tightly against the bottom of the ship, without any hindrance to the navigation of the ship.

This invention discloses an adaptive stability adjustment device for the heave motion of an amphibious vehicle and its working method. The device includes a fixed deck at the stern of the amphibious vehicle, a folding deck at the bow, and buffer decks on both sides of the amphibious vehicle. The fixed deck is fixedly connected to the stern and has semi-cylindrical strip structures evenly spaced at its bottom. The folding deck is rotatably connected to the bow via a rotating shaft and has cylindrical strip structures evenly spaced at its bottom. This invention, through the folding and fixed decks, combined with buffer decks at different positions on both sides of the amphibious vehicle, can quickly adjust the large-amphibious heave motion of the amphibious vehicle after being impacted by waves, based on the principle of increasing impact resistance and restoring torque, allowing it to reach an adaptive dynamic equilibrium state in a short time.

The invention relates to the technical field of offshore wind power generation, in particular to an offshore wind power floating platform anti-overturning structure which comprises a platform body, a ballast tank, an adjusting valve, a conveying pump, a ballast collecting unit, a damping unit, an intelligent detection unit and a central control unit. The damping unit is movably arranged on the outer side of the platform body and connected with the central control unit, the intelligent detection unit is fixedly arranged on the outer side of the platform body and connected with the central control unit, the ballast tank is fixedly arranged on the inner side of the platform body, and the input end of the conveying pump is connected with the outer side of the ballast tank through a pipeline and electrically connected with the central control unit. The adjusting valve is connected with the ballast tank through a pipeline and electrically connected with the central control unit, the ballast collecting unit is fixedly arranged in the ballast tank and connected with the central control unit, and therefore the anti-overturning effect of the platform is achieved.

The invention provides a passive stabilization system of a floating type fan foundation and the fan foundation, the passive stabilization system comprises a first water tank, a second water tank and a third water tank, and the first water tank, the second water tank and the third water tank are enclosed to form a triangular structure. Each water chamber comprises a horizontal main body section, a first vertical section and a second vertical section, the first vertical section and the second vertical section of each water chamber are respectively positioned at two ends of the horizontal vertical section, and the first vertical section is communicated with the second vertical section through the horizontal vertical section; the two adjacent vertical sections of the two adjacent water tanks are located in the same stand column of the draught fan foundation. Along the extension direction of each water tank, the difference between the inherent frequency of each water tank and the inherent frequency of the fan foundation in the corresponding direction is not more than 5%. The first water tank, the second water tank and the third water tank are each provided with a first control valve. The problems that in the prior art, fan foundation stabilization equipment is poor in effect, prone to failure and large in energy consumption are solved.

The invention provides a ship energy feedback suspension system and a cooperative control method thereof, and relates to the technical field of ship energy conservation and vibration reduction control. The TPMLG is integrated to serve as an energy converter and a variable damper, and three subsystems of energy feedback execution, energy management and cooperative control are combined, so that efficient conversion from wave energy to electric energy and intelligent suppression of ship motion are achieved; according to the system, cooperative control of three modes of energy recovery priority, stable balance and high damping priority can be dynamically switched according to sea conditions, power generation and vibration reduction performance is optimized through wavelet analysis and duty ratio adjustment, and the key technical problems of energy conservation, carbon reduction, endurance improvement, sailing stability and the like of the ship are synchronously solved.

The invention belongs to the technical field of ship equipment, and discloses a wave suppression device and a ship. The wave suppression device comprises a hinge six-bar mechanism, a spoiler sheet and a rotary driving part, and the rotary driving part drives the spoiler sheet to rotate through the hinge six-bar mechanism, so that the spoiler sheet has a working position extending into water. The first connecting rod is adopted for continuous rotation driving, through hinged transmission of the fourth connecting rod and the spoiler sheet, the swing angle of the spoiler sheet is naturally limited by the rotation range of the first connecting rod, a rigid stroke tail end does not need to be arranged, a rotation driving piece is allowed to rotate continuously, reversing is not needed, and the overshoot phenomenon of traditional reciprocating motion is avoided; the problems of vibration, abrasion and control deviation caused by overshoot are eliminated in principle.

The invention discloses a liquid tank oscillation stopping device and a floating platform, and relates to the technical field of liquid tank oscillation stopping. The liquid tank oscillation stopping device comprises an oscillation stopping plate movably arranged in a liquid tank, and an elastic piece is connected between the oscillation stopping plate and a tank wall, so that when the oscillation stopping plate is subjected to impact acting force of liquid, the oscillation stopping plate reciprocates in the liquid tank, and then the elastic piece is compressed or stretched to absorb impact energy of part of the liquid; therefore, the direct impact on the oscillation stopping plate is reduced; the oscillation stopping plate reciprocates in the liquid tank under the action of the elastic part, so that the flowing resistance of the liquid can be increased, the shaking energy of the liquid can be further consumed (a better oscillation stopping effect is achieved), the elastic part converts the impact force of the liquid into elastic potential energy, and then the elastic potential energy is released, so that the oscillation stopping plate can continuously work; and therefore, the liquid in the liquid tank can be well stopped from swinging, the swinging stopping plate can be prevented from being subjected to overlarge impact force from the liquid, and the service life of the swinging stopping plate can be prolonged.

The invention provides a floating platform and a marine environment adaptability testing method. The floating platform includes: a floating body having buoyancy; the floating body comprises a plurality of lower floating barrels and a plurality of stand columns, the lower floating barrels and the stand columns are connected to form a structure with a closed outline, and one stand column is arranged between any two adjacent lower floating barrels. The damping mechanisms are uniformly arranged on the inner side wall of the floating body in the circumferential direction of the floating body; the damping mechanism comprises a fixed damping plate and a movable damping plate which are arranged in the vertical direction, and the movable damping plate can move relative to the fixed damping plate to adjust the overlap ratio between the movable damping plate and the fixed damping plate so as to adjust the damping area. Wherein the fixed connecting position of the inner side wall of the floating body and the fixed damping plate is a first connecting part, the abutting position of the inner side wall of the floating body and the movable damping plate is a second connecting part, and the movable damping plate can move to be close to or away from the second connecting part to block the space between the first connecting part and the second connecting part or expose part of the space.

The present application relates to a kind of zigzag damping device for cylindrical hull, including cylindrical hull and three damping box body.Three damping box body is same shape, and it is arranged at the bottom of the side of the cylindrical hull at equal intervals.Damping box body includes rotary box and multiple tooth-shaped box.Rotary box and tooth-shaped box are both shell plate structure, and independent of each other.Tooth-shaped box is closed shell plate structure, not communicated with seawater, inside is empty cabin, not load ballast water.Tooth-shaped box is same shape, horizontal section is arc side trapezoid or arc side triangle, vertical height is same with the vertical height of the outside of rotary box, convenient to be welded on the outside of rotary box.Tooth-shaped box and rotary box are independent of each other, and the welding strength between tooth-shaped box and rotary box is lower than the welding strength between rotary box and cylindrical hull, and the damage or drop of single or multiple tooth-shaped box will not cause greater influence to the stability, safety etc.of cylindrical FPSO.