KR20010108057A - Offshore turret upper bearing - Google Patents

Abstract

The present invention relates to a marine system having a turret (20) fixed to a seabed and connected to a ship hull (14) by at least an upper bearing assembly (34) so that the hull can move in a wind direction about the turret. The upper bearing assembly is manufactured with high reliability and low cost. In some configurations, the upper bearing assembly includes an upper slider bearing ring 40 and a lower slider bearing ring 42 facing adjacent to each other at the interface 44, wherein the upper bearing ring is fixed to the turret and the lower bearing ring Is supported to the hull through an amount of elastomeric material 102. The elastomeric material allows the upper portion of the turret to tilt slightly without opening the gap on one side of the interface. The lower bearing ring is separated into segments 112A and 112B such that when the turret is tilted too much, pressurized lubricant may leak from one or several segments, and the lower bearing ring begins to rise while the turret is tilted. In another configuration, a circularly arranged bearing mechanism 202 is provided, each bearing mechanism including a cylinder 224 and a piston 226 and a source of pressurized fluid supplied to the bearing mechanism.

Description

Offshore bearing turret {OFFSHORE TURRET UPPER BEARING}

Previously, the upper bearing assembly was a roller bearing, which had less friction so that the turret rotates only a few degrees before the roller rolls. However, the use of roller bearings has serious disadvantages. One disadvantage is that reliable roller bearings require raceways to be forged before machining to provide strength that resists the cohesion of individual rollers. At present, there are no forging mechanisms in the world that can forge pipelines of diameter 8 m or more. Some large turrets have diameters up to 12 m. The conduit can be formed from forged segments welded together, but this results in a nonuniformity of the conduit surface under load and a weakening of the strength. In addition, the cost for large roller bearings is very expensive. It is worthwhile to have an upper bearing structure, in particular a bearing structure for large turrets of 8 m or more in diameter, which supports the weight of the turret to the ship hull and overcomes the above mentioned disadvantages.

One type of offshore system is a turret that lies outside the ship's hull moon pool or hull, and allows the vessel to move around the turret in accordance with the wind direction (unrestricted rotation about the vertical axis). Bearing structure). The turret is fixed to the seabed and the fluid line generally extends from the well or pipeline at the seabed to the turret. The bearing structure includes an upper bearing assembly and often a lower bearing assembly. The upper bearing assembly supports the weight of the turret and the weight of the mooring structure and the hoses attached thereto, which can reach thousands of tons.

1 is a partial cross-sectional view of an offshore system constructed in accordance with the present invention.

FIG. 2 is a cross-sectional view of a portion of the upper bearing assembly of the system of FIG. 1. FIG.

3 is a view of a portion of the upper bearing assembly of FIG. 2, in which the turret is tilted sufficiently so that one side of the upper bearing ring is lifted from the lower bearing ring;

4 is a view taken along line 4-4 of FIG. 1, showing the lower bearing ring;

5 is a partial perspective view of the lower bearing ring of FIG. 4.

5A is a partial perspective view of an optional bearing ring that may be used instead of that shown in FIG. 5.

FIG. 6 is a view taken along line 6-6 of FIG. 5, showing a portion of the upper bearing ring; FIG.

FIG. 7 is a view taken along line 7-7 of FIG. 5, showing a portion of the upper bearing ring; FIG.

8 is a schematic diagram of a flow control device of the upper bearing assembly of FIG.

9 is a partial plan view of the lower bearing and pressurized lubricant source of FIG. 4;

10 is a partial perspective view of an upper bearing assembly of another embodiment of the present invention.

11 is a cross-sectional view of one of the bearing mechanisms of the upper bearing assembly of FIG. 10.

According to one embodiment of the invention, an upper bearing assembly is provided to support the turret to the ship hull, which assembly can be configured with a diameter of at least 8 m and can be constructed at less cost than roller bearings. The upper bearing assembly comprises upper and lower slider bearing rings, which bearings face adjacent to the interface with the upper bearing ring connected to the turret. The pressurized lubricant source is coupled to the interface, so that most of the load at the interface is absorbed by the pressure lubricant. The support structure for supporting the lower bearing ring on the hull comprises a certain amount of elastomeric material spaced about the axis, which allows the lower bearing ring to tilt slightly when the upper portion of the turret is tilted.

One of the bearing rings, such as the lower bearing ring, may comprise a plurality of fluid seals, which divide the bearing ring into segments spaced in the circumferential direction. The pressurized lubricant source includes a plurality of outlets for individually supplying pressurized lubricant to each segment. Therefore, when the turret is greatly inclined so that one side of the upper bearing ring is lifted from the corresponding side of the lower bearing ring, the pressure of the fluid is maintained in the remaining portion of the segment which is not so raised.

According to another embodiment of the present invention, a plurality of bearing mechanisms are provided which can be arranged in a circle to support the turret to the hull. Each bearing mechanism comprises a cylinder and a piston, one lying on the turret bearing surface and the other against the bearing surface of the ship hull. A pressurized fluid source is coupled to each bearing mechanism with the force of the piston on the bearing surface mainly absorbed by the pressurized fluid.

The novel features of the invention are described in detail in the appended claims. The invention is best understood from the following description with reference to the accompanying drawings.

1 illustrates a marine system 10 comprising a vessel 12 with a vertical opening or moon pool 16 housing the turret 20 provided in the hull 14. The mooring structure 22 extends from the turret to the seabed 24 to limit the floatation of the vessel. The illustrated mooring structure includes several long and heavy chains, which extend along the mooring along the mooring structure in the form of a catenary curve, but vertical risers and other mooring structures may be used. Can be. Fluid conduit 26 extends from the well of the seabed or the pipeline of the seabed to the turret. The hull 14 can move in accordance with the wind direction, that is, it can rotate without limitation about the vertical axis 30 in accordance with the change in the wind direction and the current. However, the turret 20 is usually not rotatable, that is to say it can not rotate without limitation, and generally does not rotate more than about 10 degrees.

The bearing structure 32 that rotatably connects the turret to the hull includes an upper bearing assembly 34 and a lower bearing assembly 36. In general, the upper bearing assembly 34 supports almost or all of the vertical weight of the turret and the load on the turret. As shown in FIG. 1, when the turret has a large length and the lower part 35 of the turret is located near the bottom of the hull, a lower bearing assembly 36 is provided so that generally a radial load, i.e. the ship chain Most of the horizontal component of the load from one chain when suspended in the direction of increasing tension. However, it is generally necessary to provide some radial support capability to the upper bearing assembly 34. In harsh weather, the turret and / or hull may be deformed, which may cause the top 39 of the turret to tilt. In the roller bearing assembly, tilting is avoided by the upper and lower roller sets, but this further increases the cost of the roller bearings.

According to one embodiment of the invention, as shown in FIG. 2, an upper bearing assembly is formed that includes an upper slider bearing ring 40 and a lower slider bearing ring 42 facing adjacent to each other at an interface 44. . The upper bearing ring 40 is connected to the turret, while the lower bearing ring 42 is shown as part of the lower ring structure 80 that is connected to the ship hull through the support structure 46. A source 50 of pressurized lubricating oil, such as oil, water soluble lubricant or even water or other liquid, is connected to the interface 44 to apply the pressurized fluid lubricant there. The illustrated source has a reservoir 52 and a pump 54, which pumps fluid under high pressure through a passage 56 leading from the reservoir 52 to the interface 44. If the turret does not tilt too much, the pair of seals 60, 62 prevent lubricating oil from leaking out of the area of the interface. The radially inner bearing portion 64 and the outer bearing portion 66 form a radial interface region 70 to provide radial support capability to the upper bearing assembly. When the hull swings from side to side or back and forth, the low pressure seals 74 and 76 prevent the leakage of lubricating oil.

The lower ring structure 80 forms a ring-shaped channel 86 with an open top, which receives an upper bearing portion 82 fixed to the turret. Despite the application of pressurized lubricating oil at interface 44, the leakage of oil is minimal due to the above-described structure and seal, and return passages such as 84 to return any leaked oil to reservoir 52. It is desirable not to have a holddown bearing which prevents the turret from tilting and one side of the upper bearing portion 82 correspondingly raised, which strengthens the turret and hull at an increased cost. It requires you to do it.

3 shows a state in which the turret is tilted so that one side of the upper slider bearing ring 40 is raised from the interface 44 and the lower slider bearing ring 42. Due to such a rise, the seals 60, 62 do not retain pressurized lubricant in the interface region. In the present invention, the pressurized lubricating oil is discharged through the outlet passage connected to the lubricating oil reservoir via the valve 94 without holding such pressurized lubricating oil. The valve 94 permits the discharge of fluid only if the pressure exceeds a predetermined level, which level is higher than the level maintained in the radial interface region 70. For example, if the pressure at interface 44 is generally maintained at 107 kPa (15 psi) and the radial interface 64 is maintained at 10 kPa (1.5 psi), valve 94 may be at a pressure of 20 kPa (3 psi) or more. It can be opened when it reaches. The tilt causes the fluid pressure at the interface 44 to abruptly decrease, and the resultant relaxed pressurized fluid exerts only a small upward force on the rising side of the upper bearing ring 40. The method described below is employed to ensure that opposite sides of the interface are continuously supported by the pressurized fluid.

A sudden decrease in fluid pressure at interface 44 caused by tilting occurs even when only slightly tilted. Applicants have designed a structure that requires a large amount of inclination before there is a sudden release of lubricating oil pressure on one side by appropriately selecting a support structure 46 for supporting the lower bearing portion 80 to the ship hull. The support structure 46 includes a plurality of supports 100, each support comprising a predetermined amount of elastomeric material 102. The elastomeric material 102 is a plate-shaped elastomeric material separated by a steel plate 104. The elastomeric material 102 is in a compressed state, but the amount of compression varies with the load applied to it. If the turret is tilted and thus the load on one side of the lower bearing portion 80 suddenly decreases significantly, the previously compressed elastomeric material 102 expands, thereby keeping the upper bearing ring and the lower bearing ring together closely. Can be. As shown in FIG. 1, the support structure 46 includes a plurality of supports 100, which are arranged with twelve supports 100 spaced in the circumferential direction about an axis 30. Show the system. Therefore, by using the elastomeric material in the support structure for the upper bearing assembly, the upper slider bearing ring can be gently inclined with respect to the lower slider bearing ring without raising of one side. However, when a rise occurs, the lubricating oil pressure suddenly decreases on the side of the upper bearing ring that rises from the lower bearing ring, thereby reducing the amount of tilt.

4 and 5 illustrate the structure of the lower slider bearing ring 42. The bearing ring includes a recess 110 that forms segments 112 that are spaced circumferentially about the turret axis 30. The particular ring shown includes six of these segments 112A- 112F, each segment corresponding at an angle A of 60 °. The recess leaves radially inner and outer slide surfaces or regions 114, 116, with recesses provided therebetween. Seals 60, 62 (see FIG. 5) are placed in the grooves of the inner and outer slide surfaces, respectively. FIG. 6 shows that the lower surface 120 of the upper bearing ring 40 lies adjacent to the radially outer sliding surface 116, with the membrane 122 of lubricating oil therebetween. 5 shows that outlet 123 is connected to each recess to supply pressurized oil to the entire recess. The recess 110 dispenses pressurized lubricant. As long as the pressure of the lubricant is maintained, an upward force is provided to the upper bearing ring at the full width of the interface between the high pressure seals 60, 62. 9 shows that each flow line 127 and shutoff valve 125 that carry fluid to the recess are connected in series. Each valve 125 blocks flow when the pressure on the downstream side of the valve drops to 7 kPa (1 psi) below the pressure on the upstream side.

On the lower ring there is provided an inner slide surface 114 and an outer slide surface 116 supporting the upper ring. Due to the presence of the recess, it is necessary to precisely finish (eg by grinding and / or polishing) only the reduced surface area of the upper and lower bearings, which are reduced by the inner sliding surface 114 and the outer surface. The sliding surface 116 and the corresponding region 117 of the upper bearing ring. When the lubricant pressure is lost, wear is concentrated on the inner and outer surfaces, but this is only expected to happen. Surface areas 118 and 119 of the bearing ring can be left unfinished, thereby reducing costs. Each bearing ring 40, 42 may be composed of parts welded or cast together, since they do not have to withstand large cohesion, such as rollers.

According to the invention, the segments 112A and 112B (see FIG. 5) are sealed to each other by the segment seal 124. Each segment seal is placed in a radial groove 126 formed in the spoke area 130 of the lower bearing ring 42. As shown in FIG. 7, the spoke area 130 is preferably slightly recessed from the inner slide surface 114 and the outer slide surface 116, so that the spoke area 130 needs to be precisely finished. none. In addition, the segment seal 124 may not seal the inner slide surface seal 60 and the outer slide surface seal 62. However, it is not harmful for some leakage to occur through the segment seal 124 because such leakage only permits very little flow of pressurized lubricant to adjacent segments where the pressure suddenly drops due to the inclination of the turret.

Instead of using segments sealed together, it is possible to use a continuous lower slider bearing ring. 5A shows a portion of this continuous lower bearing ring at 42X. Due to the presence of elastomeric material 102 (see FIG. 2) in the support structure 46 supporting the lower slider bearing ring on the hull, the loss of lubricating oil pressure is avoided in all cases except very large tilt forces.

8 illustrates a fluid control device 140 that controls the pressure of the fluid at the interface between the upper slider bearing ring 40 and the lower slider bearing ring 42. Typically, the vessel is held in a predetermined direction with a minimum rotation of only a few degrees or less in either direction for a long period of time (multiple hours). In order to minimize wear to the pump and to prevent leakage when high pressure lubricant is not required, the supply of pressurized lubricant is stopped in the present invention when the hull is not rotating. 2 shows a sensor 142 for sensing the torque transmitted to the upper slider bearing ring 40 by the turret. As shown in FIG. 8, the torque sensor 142 sends an output value to the control circuit 144, where the torque sensor is a resistor whose resistance changes in accordance with the sensed torque. If little or no torque is sensed, the control circuit opens switch 146 to prevent electrical, hydraulic or pneumatic flow from pump 150 through pump 54 for operation of the pump. When the torque sensor senses a torque exceeding a predetermined level, the control circuit 144 closes the switch 146 to start the pump, whereby the pump delivers lubricant from the reservoir 52 to the lower bearing ring 42. To the head).

In one example, the hull of the ship rotates 5 ° about the vertical axis of the turret, and the turret rotates with the hull, resulting in an increase in tension on the catenary chain shown in FIG. The turret tends to rotate back towards its initial position. When this level of torque is detected, the control circuit can start the pump. Lube oil pressure increases as shown by graph 152. The control circuit changes the pressure by controlling the valve 154, which can constrain the path along which the lubricant flows. As shown in graph 156, the valve 154 adjusts the lubricant pressure by increasing and decreasing the lubricant pressure by 5% every 2 seconds for a period of one minute when a sufficient working lubricant pressure is reached. It works. This adjustment of lubricating oil pressure assists in overcoming the static friction at the interface of the upper and lower bearing rings, thus allowing the turret to be easily rotated back to its stop position (the chain is not twisted). Thereafter, the lubricating oil pressure can be kept or changed unchanged, for example in response to a vertical load on the turret.

When the ship travels in the wind direction, the ship rotates at a very low rotational speed of one revolution per ten minutes and almost always at a speed of less than one revolution per minute. In a bearing ring with a diameter of 20 m and a rotational speed of one revolution per minute, the surface of the bearing ring moves at a speed of 1 m / sec or 2 miles / hr. As a result, the rotational speed of the upper bearing ring hardly affects the bearing performance. Also, because the rotation is not fast or continuous in one direction, the friction loss is not important, only the ability to rotate with the appropriate torque.

According to the present invention, it is preferable to control the lubricating oil pressure, so that a substantial weight, such as 10% of the total, is supported by the inner slide surface 114 and the outer slide surface 116 (see FIG. 5). As an example, the average diameter (B; see FIG. 4) of the bearing rings is 20 m, the width (C) of each bearing ring is 1.5 m, and the widths (D; see FIG. 6) of the outer and inner slide surfaces are respectively 20 cm. The downward load supported by the upper and lower bearing rings is 2000 metric tons. If the lubricant pressure is about 15 psi or 107 kPa, the entire weight can be supported on the pressurized lubricant, but a lubricant pressure of 96 kPa can be used with the inner and outer slide surfaces supporting about 10%. The lubricating oil pressure may be adjusted according to the load by using a load sensor disposed at approximately the same position as the sensor 142 of FIG. 2.

10 shows another upper bearing assembly 200 that includes a group of bearing mechanisms 202. The bearing mechanism supports the upper bearing portion 204 of the turret 206 to the lower bearing portion 210 of the ship hull 212. The bearing mechanism 202 is defined by a circular track 214 concentric with the axis of rotation 216 of the turret. The circular track is formed by the inner track wall 220 and the outer track wall 222 of the hull.

11 shows that each bearing mechanism 202 includes an upper element 224 and a lower element 226. The upper element includes an upper surface 230 that abuts against the upper bearing surface 232 of the turret bearing portion. The lower element lies within the upper element. The lower element includes a bottom surface 234 at least whose seal 236 is supported against the lower bearing surface 238 of the lower bearing portion of the hull. Pressurized fluid 240 such as oil (eg, 100 psi) is placed within the instrument 202 to push the element away.

A medium pressure face seal 236 seals the lower surface 234 of the lower element against the lower bearing surface 238. The medium pressure radial seal 242 seals the gap 244 between the outer side of the lower element and the inner side of the upper element. As a result, pressurized fluid 240 is trapped between the elements, pushing the upper element upwards, and pressing the lower element downward. The downward force on the lower element is equal to the area in the ring region 250 multiplied by the pressure of the fluid. The pressurized fluid is urged directly against the lower bearing surface 238 over the diameter 252 of the circle. It can be seen from FIG. 11 that the diameter 252 + 2 x 250 of the bearing mechanism is greater than its height 254.

The elements 224, 226 operate similarly to cylinders (not necessarily cylindrical) and pistons so that the upper element can move upwards or downwards by an appropriate amount up to 2 cm. The gap 244 is large enough to allow the upper element to tilt at least 0.5 °, preferably at least 1 ° (most pistons can be tilted by less than (1/4) ° in the cylinder). As a result, even if the turret and / or hull are deformed in harsh weather so that the distance 254 between the bearing surfaces 232 and 238 is slightly changed, or the turret and / or hull is tilted away from parallel, the bearing mechanism The turret can still be supported on the hull. Typically, due to this bias, the distance for the bearing mechanism on one side of the turret increases while the distance for the bearing mechanism on the opposite side of the turret decreases. As an example, the outer diameter of each bearing mechanism is 1 m.

10 illustrates a pressurized fluid source 260 connected to fluid conduit 264 through manifold 262, each extending to one of the bearing mechanisms 202. Only one bearing mechanism per two receives the pressurized oil and supports the turret along with other bearing mechanisms that are useful as spares. 11 shows the hole 270 of the upper element and the pipe 272 of the conduit coupled to the hole 270, which extends through the hole 274 of the turret portion 204. The top of the pipe is connected to the pipe 264 via a swivel joint 276, which extends from the manifold. The bearing mechanism 202 rotates with the turret as the turret rotates, but the bearing mechanism may rotate about its own axis 278.

When the turret rotates (eg, by 10's of degrees), the outer wall 280 of the upper or outer element 224 slides along the inner track wall 220 and the outer track wall 222 or For example, you can rotate on one track wall and slide on another track wall. Lubrication oil near zero pressure is maintained inside the element to minimize friction. Low pressure seals 282, 284 prevent spillage when the vessel is tilted, and gravity pipe 286 may return excess oil to the reservoir. FIG. 11 shows, in phantom, an extension 288 of the outer wall supporting the radial bearing 290 that keeps the upper end of the turret centered about its axis.

The pressure of the oil may be set slightly lower than the pressure required to maintain the upper element 224 above the upper surface 290 of the lower element or to maintain the lower element 292 of the lower element above the lower bearing surface 238. As a result, the upper element may be pressed with a weak force against the surface 290. The advantage of this is that the turret does not rise or fall due to small fluctuations in the load or fluid pressure on the turret. Preferably, the pressure is adjusted to increase the fluid pressure when the turret weight increases to some extent (such as when the mooring chain is lifted from the seabed). The pressure can be closely adjusted to maintain the state of FIG. 11. Although a door 294 is provided to replace a damaged bearing mechanism, a spare already exists.

Therefore, the present invention provides an upper bearing assembly that supports the turret to the ship hull, which assembly can be reliably manufactured in a very large size and at a reasonable cost. In one assembly, the upper bearing assembly includes upper and lower slider bearing rings lying adjacent to the interface, and it is desirable for the pressurized lubricant at the interface to support most of the weight. The lower bearing ring can be supported by an amount of elastomeric material spaced about the turret axis. One of the bearing rings, such as the lower bearing ring, can be divided into circumferentially spaced sectors to prevent pressure loss in all sectors. In other assemblies, the plurality of bearing mechanisms forming the piston and cylinder may be constrained by the track and biased away by the pressurized fluid, such that the bearing mechanism supports the turret to the ship hull. The upper bearing structure is useful for ships used in many different applications, including the generation of hydrocarbons from subsea wells and for drilling ships drilling such wells.

While specific embodiments of the present invention have been illustrated and described so far, it will be apparent to those skilled in the art that modifications and variations can be readily made, and consequently, the claims are intended to cover such modifications and equivalents.

Claims (14)

A ship hull 212 which floats in the sea and can move according to the direction of the wind and is provided with a vertical opening 16, a turret 206 disposed in the opening, a mooring structure 22 extending from the turret to the seabed, 10. A marine system having a bearing structure 32 rotatably supporting said turret to said vessel and comprising an upper bearing assembly 200, The upper bearing assembly includes upper and lower bearing portions 204 and 210 with bearing surfaces 232 and 238 substantially facing each other, the upper bearing portion being connected to the turret, and the lower bearing portion being the hull. Connected to A plurality of individual bearing mechanisms 202 are disposed between the upper bearing surface and the lower bearing surface, each bearing mechanism having an upper surface 230 and a lower surface 234 abutting against the upper and lower bearing surfaces, respectively. An upper element and a lower element, the elements being slidable relative to one or more of the bearing surfaces, the upper element and the lower element biased away but movable about perpendicular to each other, Each bearing mechanism has a diameter greater than its height measured between the upper and lower surfaces, providing stability despite movement. The offshore system according to claim 1, wherein the upper and lower elements of each bearing mechanism can be inclined at least 0.5 ° relative to each other so that the ship hull can be deformed while still supporting the turret during its rotation. . 2. The lower bearing portion of claim 1 further comprises a concentric inner track wall 220 and an outer track wall 222 defining a circular track 214 therebetween, wherein the bearing mechanism is disposed between the tracks. , Lubricating oil (240) lies on the lower bearing surface and is confined between the track wall. The method of claim 1, wherein a cavity is formed between the elements, and means 264 for supplying pressurized fluid to the cavity to displace the element away from it, The surface (234) of the one element is open to the corresponding surface of the bearing surface (238) and is marine system characterized in that it is sealed against the corresponding bearing surface. A ship hull 212 which floats in the sea and can move according to the direction of the wind and is provided with a vertical opening 16, a turret 206 disposed in the opening, a mooring structure extending from the turret to the seabed, and the turret An offshore system having a bearing assembly 200 rotatably supporting a vessel, The bearing assembly includes upper and lower bearing portions 204 and 210 with bearing surfaces 232 and 238 substantially facing each other, the upper bearing portion being connected to the turret, and the lower bearing portion being connected to the hull. Connected, A plurality of individual bearing mechanisms 202 are disposed between the upper bearing surface and the lower bearing surface, each bearing mechanism being respectively abutted against the upper and lower bearing surfaces, the upper element 224 and the lower element 226. Wherein the upper and lower elements are spaced apart but are movable about perpendicular to each other, The lower bearing portion comprises approximately vertical walls 220, 222 with circular tracks 214 formed therebetween, wherein the individual bearing mechanisms are disposed within the tracks and between the approximately vertical walls and the tracks. Offshore system, characterized in that it comprises a lubricating fluid (240). 6. The method of claim 5, wherein the lower element is open to the lower bearing surface, wherein the lubricating fluid forms a film of fluid, in which the lower element moves on the lower bearing surface, wherein the lubricating fluid is between the elements. An offshore system, characterized in that it acts as a hydraulic pressure for pushing up the upper element. A ship hull structure 212 which floats in the sea and is capable of moving in accordance with the wind direction and is provided with a vertical opening 16, a turret structure 206 disposed in the opening, and a mooring device 22 extending from the turret structure to the seabed. And an upper bearing assembly (200) rotatably supporting the turret structure at least partially to the vessel structure, The upper bearing assembly includes upper and lower bearing portions 204 and 210 having ring-shaped bearing surfaces 232 and 238 substantially facing each other, the upper bearing portion being connected to the turret structure, the lower bearing portion being the Connected to the hull structure, one or more of the structures forming an inner track wall 220 and an outer track wall 222 approximately perpendicular to the inner and outer sides of the ring-shaped bearing surface, A plurality of individual bearing mechanisms 202 are disposed between the upper bearing surface and the lower bearing surface, and between the inner and outer track walls, each bearing mechanism being positioned abutting against the upper and lower bearing surfaces, respectively. An element 224 and a lower element 226, the first upper element 224 forming a cylinder with a face 230 pressed against the first bearing surface, and the second lower element 226. Constitutes a vertically movable piston in the cylinder, the piston comprising a face seal 236 that abuts against a second bearing surface, one of the elements being the piston as it moves up and down; A radial seal 242 sealing against the cylinder, Means (264) for supplying pressurized fluid between the elements to offset the elements away. 8. The marine system of claim 7, wherein each piston comprises an area in the face seal, which is at least half of the piston area in plan view. A ship hull 14 which floats in the sea and can move in accordance with the direction of wind and is provided with a vertical opening 16, a turret 20 disposed in the opening, a mooring structure 22 extending from the turret to the seabed, 10. A marine system having a bearing structure 32 rotatably supporting said turret to said ship and comprising an upper bearing assembly 34, The upper bearing assembly includes an upper slider bearing ring 40 and a lower slider bearing ring 42 that are placed adjacent to each other at an interface, the upper bearing ring connected to the turret, and the lower bearing ring connected to the hull. , Pressurized lubricant supply source 50 is connected to the interface, The first slider bearing ring includes a plurality of fluid seals 124 at the interface, which separates the first slider bearing ring into a plurality of segments 112 spaced circumferentially about an axis. And said pressurized lubricating oil source has a plurality of outlets (123) for supplying pressurized lubricating oil, respectively, wherein at least one outlet is open to said respective segment. 10. The system of claim 9, comprising a plurality of support structures 46 spaced circumferentially about the axis, each of which supports a predetermined position along the lower slider bearing ring on the hull, respectively. The support structure of the offshore system comprises a predetermined amount of elastomeric material (102) supporting the weight of the turret and the load on the turret. 10. The interface of claim 9, wherein the interface has radially inner and outer regions and includes an inner seal 60 and an outer seal 62, respectively sealing the inner and outer regions of the interface, wherein the outer seal is formed of an interface. A marine system, characterized in that it is configured to quickly leak pressurized lubricating oil from an external location beyond a predetermined thickness, preventing the turret from tilting. A ship hull 14 which floats in the sea and is capable of moving in accordance with the wind direction and is provided with a vertical opening 16, a turret 20 disposed in the opening, a mooring structure 22 extending from the turret on the vessel, An offshore system having an upper bearing assembly 34, The upper bearing assembly comprises an upper bearing 80 and a lower bearing 82 which are placed adjacent to each other at an interface, an upper bearing connected to the turret, a lower bearing ring connected to the hull, A pressurized lubricant supply source 50 connected to the interface; It has a sensor 142 for detecting that the hull rotates or does not rotate relative to the turret, Said sensor being connected to said source and controlling said source to supply high pressure lubricant to said interface when the hull is not rotating. A ship hull 14 which floats in the sea and can move in accordance with the direction of wind and is provided with a vertical opening 16, a turret 20 disposed in the opening, a mooring structure 22 extending from the turret to the seabed, 10. A marine system having a bearing structure 32 rotatably supporting said turret to said ship and comprising an upper bearing assembly 34, The upper bearing assembly includes an upper bearing 80 and a lower bearing 82 that are placed adjacent to each other at an interface, an upper bearing connected to the turret, a lower bearing connected to the hull, A pressurized lubricant supply source 50 connected to the interface; And a sensor 142 for detecting when the lower bearing starts to rotate relative to the upper bearing after not rotating, The sensor is connected to the source and controls the source to appropriately regulate the pressure of the fluid supplied to the interface when the lower bearing starts to rotate. A ship hull 14 which floats in the sea and can move in accordance with the direction of wind and is provided with a vertical opening 16, a turret 20 disposed in the opening, a mooring structure 22 extending from the turret to the seabed, 10. A marine system having a bearing structure 32 rotatably supporting said turret to said vessel and comprising an upper bearing assembly 34, The upper bearing assembly includes an upper slider bearing ring 80 and a lower slider bearing ring 82 which are placed adjacent to each other at an interface, the upper bearing ring is connected to the turret, and the lower bearing ring is supported on the hull. Become, And a pressurized lubricant supply source 50 connected to the interface, It does not have a hold down bearing mechanism that prevents one side of the upper slider bearing ring from rising relative to the lower slider bearing ring when the upper portion of the turret is tilted, The upper bearing assembly is characterized in that it comprises means 62 which allow the main slider to leak primarily from the pressurized lubricating oil from only one side of the interface when the upper slider bearing ring is lifted from the lower slider bearing ring while the turret is tilted. Marine system.