boat lift

Abstract

Offshore platform with a lifting and lowering device (8) with a carriage for receiving a boat (9) and with at least two angled arms (14, 16) which are offset in the direction of a pivoting movement on a bottom surface (7) of a platform facing a sea surface (4) and are arranged offset in the same way on the carriage (12) and pivot the carriage (12) from a lowered position below the sea surface (4) to a raised position at the level of a top surface (11) of the platform and hold the carriage (12) at the same angle to the sea surface (4) during the pivoting movement, characterized in that the lifting and lowering device (8) is rotatably arranged on a slewing ring (13) on the bottom surface (7).

Description

[0001] The invention relates to an offshore platform device with a lifting and lowering mechanism. The invention also relates to a method for lifting a boat from the sea onto the upper surface of an offshore platform and a method for lowering a boat from the upper surface of an offshore platform into the sea.

[0002] Typically, workers are transported to and from an oil rig by boat. They then ascend from the boat to the platform using ladders or similar devices, and vice versa. This method is relatively unsafe, as workers can fall from the ladders and injure themselves. Alternatively, personnel can be exchanged by helicopter. This method is expensive and requires a suitable landing deck along with other support systems.

[0003] From WO 2015 / 105 420 A1, a ship with a movable platform is known, from which a gangway leads to a tower or similar structure.

[0004] In the older law WO 2018 / 069 241 A1, a ship with a lifting device for a boat is disclosed, the lifting device being installed on the top of the platform.

[0005] In DE 10 2012 112333 A1 a launching and recovery device for a floating device is disclosed, which is arranged on the top of a platform.

[0006] In DE 20 2011 001 460 U1 a dinghy receptacle on a yacht is disclosed, wherein the dinghy can be moved from the deck to the dinghy receptacle and back by means of a rail guide.

[0007] US Patent 6,138,605 A discloses a lifting device for a boat with two angularly arranged arms that are articulated and lift the boat from the water onto an offshore platform by means of a cable-pull mechanism. A disadvantage of this device is the relatively complex cable-pull mechanism, which has several cables that must be shortened in a coordinated manner.

[0008] CA 2 009 908 A1 discloses a lifting and lowering device for a boat, which has an angled arm rotatably mounted in a lower section of a support leg just above the water surface. The arm is raised and lowered by means of a cable pulley system. A disadvantage of this design is the pulley, which is particularly cumbersome when the arm is lowered.

[0009] US 2012 / 0141233A1 concerns a yacht with an inflatable boat receptacle located at the stern, which allows the inflatable boat to be lifted in a pivoting motion while the receptacle platform remains horizontally aligned.

[0010] GB 2 372 495 A discloses a lifting device for a ship, which is arranged on a sloping underside of the ship. A disadvantage of this lifting device is not suitable for mounting on a horizontal, stationary platform underside.

[0011] Particularly in offshore wind energy, periodic maintenance work must be carried out on each individual wind turbine. This requires a correspondingly large amount of personnel. Currently, wind turbines cannot be serviced by helicopter, but only by small boats.

[0012] It is therefore an object of the present invention to provide an offshore platform as mentioned above which reduces the aforementioned disadvantage.

[0013] With regard to the device, the problem is solved by an offshore platform mentioned above with the features of claim 1.

[0014] The offshore platform according to the invention rests on the seabed by means of support legs. The platform has a gap between its underside and the sea level, which is large enough to allow even the largest imaginable waves to pass underneath the platform. Boats are launched from mobile offshore platforms located in a wind farm for maintenance purposes, in order to dispatch maintenance personnel to the individual wind turbines. The device according to the invention makes it possible to safely launch and lower the boats themselves, including the maintenance personnel on board, to and from the top of the platform.

[0015] In this context, an offshore platform is understood to be a structure comprising the actual platform with its upper surface and its superstructure, and also including the underside, which faces the seabed. The upper surface is also referred to as the deck.

[0016] The lifting and lowering device according to the invention is arranged on the underside of the platform. It has at least two angled arms which are articulated to the underside of the platform offset in the direction of the pivoting movement and are arranged in a similarly offset manner on a carriage. The two arms are coupled to each other in such a way that they raise the carriage both from a lowered position below the water surface to a raised position at the level of the top of the platform and vice versa, and during the pivoting movement, they hold the carriage at the same angle to the sea surface, both during the lowering and the lifting movement.

[0017] Preferably, the sled is held almost, preferably exactly, horizontally, so that a boat that has traveled over the sled remains almost horizontal during both the lowering and raising movements. Preferably, the sled is inclined upwards in the direction of travel of the boat. The incline can be up to 10°. The sled is designed to rise in the landing direction of the approaching boats, so that the approaching boat first makes contact with the bottom at the bow and, through its own movement, initially lifts itself out of the water, similar to driving onto a beach. The boat travels onto and over the sled in the landing direction via an entry and exit side.

[0018] The arms each have a platform-side section that is longer than a distance between the pivot point on the underside of the platform and a platform edge, and the arms each have a seabed-side section that is longer than a distance between the underside and topside of the platform.

[0019] The dimensions of the two arm sections make it possible to move the boat laterally along the platform from a position below the underside of the platform to a position next to the platform and at the level of the top, and vice versa.

[0020] Preferably, each arm has at least two pivot points on the sled on opposite longitudinal sides, where "sled" can generally be understood as a flat frame with spacers preferably projecting away from the seabed. However, other sled configurations are also conceivable.

[0021] The width of the sled's mouth is ideally up to several boat widths to facilitate entry in rough seas. Lateral guide rollers made of elastic material further facilitate entry.

[0022] The sled is preferably designed to compensate for sea state, enabling entry even in rough seas. This can be achieved either through an active hydraulically controlled system or through appropriate buoyancy elements on the sled and a load-free hydraulic system.

[0023] Each of the two arms is advantageously hinged at four points, where "point" here also refers to a planar or spatial connection via a pivot axis or similar mechanism. A total of four hinge points are provided on the carriage, as well as at least four hinge points on the underside of the platform. However, more than two hinge points per arm are possible, particularly on the underside of the platform. This makes the connection more stable against unwanted rotational movements.

[0024] Preferably, however, the offset of the pivot points of the two different arms in the direction of rotation on the underside of the platform is the same as the offset of the pivot points of the same arms on the sled.

[0025] Preferably, the platform-side section and the seabed-side section of the arms are arranged at an angle of 90° ± 10° to each other. However, all angles between the specified angles, as well as higher and lower angles, are also disclosed.

[0026] The two pairs of arms are advantageously driven by a first cylinder and / or a second cylinder. The first cylinder is preferably connected at one end to the underside of the platform and at another end to the arm that advances during the lifting movement, while the second cylinder is preferably connected at one end to the trailing arm and at the other end to the leading arm.

[0027] The lifting and lowering mechanism is advantageously mounted on the underside of the platform so that it can rotate around a vertical axis. Therefore, the platform-side pivot points are advantageously not attached directly to the platform, but rather to a slewing ring, while the slewing ring is rotatably mounted on the underside of the platform. This arrangement is also considered a mounting on the underside of the platform.

[0028] Particularly preferably, the leading arm in the lifting direction has two lateral arms arranged laterally on the carriage and spaced apart from each other, the distance between which is greater than the width of the trailing arm. The leading arm is thus essentially fork-shaped. It can have a common platform-side section as well as the two lateral arms, which are spaced apart from each other and hinged laterally to the carriage. The distance is advantageously wide enough that, when the device is pivoted, the carriage can pivot between the two lateral arms.

[0029] Preferably, a sliding mechanism can be provided on the upper surface, allowing the boat to be moved from the upper surface onto the platform and from the platform back onto the upper surface. After the boat has been raised to the level of the platform's upper surface, it must still be moved from the platform onto the platform itself, i.e., onto the platform deck. A suitable sliding or pulling device can be provided for this purpose.

[0030] The application includes a procedure for lifting a boat.

[0031] The method is suitable for lifting a boat from the sea onto the top of an offshore platform. The method is intended for use with one of the aforementioned offshore platforms, while the aforementioned offshore platforms are also intended for use in carrying out the aforementioned methods.

[0032] According to the invention, a boat is moved in the sea on a carriage of a lifting and lowering device, the boat is positioned at least partially directly below the platform, the boat is lifted out of the water in this position partially below the platform and raised in an arc-shaped lifting motion to the level of the top of the platform. The lifting motion can be carried out by one of the aforementioned lifting and lowering devices.

[0033] Before lifting the boat, the sled is first lowered below the sea surface until it is deeper than the boat's draft, allowing the boat to pass over it. The device is then rotated around a vertical axis using a turntable, so that the entry and exit side for the boat faces away from the waves and wind (leeward). This reduces the boat's rolling acceleration and facilitates entry and exit.

[0034] The sled is then lifted, and the boat is raised in an arc-shaped pivoting motion from a position directly below, or at least partially below, the platform to a position level with the top of the platform. The height of the top of the sled and the height of the top of the platform are in the same plane, so that the boat can be pulled from the sled to the top of the platform using a horizontal pulling device.

[0035] The application describes a method for lowering a boat by lowering it from the top of a platform into the sea. This method is also suitable for use with one of the offshore platforms described above, and vice versa. The boat is pulled horizontally from the top of the platform over a carriage of a lifting and lowering device. This can be achieved using winches or similar devices that pull the boat onto the carriage via a pulley, or, when unloading, pull it off the carriage. In the first case, the cable is fixed at the end furthest from the platform; in the second case, it is fixed at the end closest to the platform.

[0036] The boat is then lowered into the sea from the top of the platform in an arc-shaped lifting and lowering motion. During this process, the boat is placed at least partially directly below, i.e., vertically, the platform. The lifting and lowering mechanism is pivoted until the carriage is deeper than the boat's draft, allowing the boat to float freely and slide off the carriage.

[0037] Preferably, the boat is first moved from a parked position on top of the platform, either laterally or otherwise, to a position directly in front of the sled. From this position, the boat can then be pulled onto the sled.

[0038] The invention is described with reference to an exemplary embodiment in seven figures. These show: Fig. 1 Side view of an offshore platform with lifting and lowering device according to the invention and boat, Fig. 2 Perspective view of the lifting and lowering device according to the invention during the lifting process, Fig. 3 Perspective view of the lifting and lowering device in a raised position, Fig. 4 the lifting and lowering device in a perspective view, Fig. 5 the lifting and lowering device in a schematic side view in a lower end position, Fig. 6 the lifting and lowering device in a schematic side view in an intermediate position, Fig. 7 the lifting and lowering device in a schematic side view in an upper end position

[0039] One in the Fig. The offshore platform 1 shown is supported on a seabed 3 by four support legs 2 and rises above a sea surface 4. The offshore platform 1 is located in Fig. 1 in an elevated operating position.

[0040] According to the invention, a lifting and lowering device 8 according to the invention is movably mounted on a platform edge 6 on an underside 7 of the offshore platform 1 relative to the offshore platform 1. The lifting and lowering device 8 is designed and suitable for lifting boats 9 individually from a sea 4a and placing them on a deck 11 of the offshore platform 1. One or more parking spaces for the boats 9 are provided on the deck 11 of the offshore platform 1. The boats 9 can be of identical construction or at least similarly constructed, or have comparable external dimensions. However, their external dimensions must not exceed certain maximum sizes, which are determined in particular by the size of a carriage 12 of the lifting and lowering device 8, nor may they exceed a weight limited by the load-bearing capacity of the lifting and lowering device 8.The lifting and lowering device 8 is attached to a slewing ring 13, which is rotatably mounted on the underside 7 of the offshore platform 1.

[0041] The lifting and lowering device 8 is located between an upper end position ( Fig. 7) and a lower end position ( Fig. 5) Continuously adjustable; "top" and "bottom" refer to orientation along the vertical. The lower end position is in Fig. 1 and Fig. 7 is shown. The upper end position is in Fig. 3 and Fig. 5 shown. An intermediate layer is in Fig. 6 shown.

[0042] The lifting and lowering device 8 is designed in its length perpendicular to the underside 7 or parallel to the support leg 2 such that the carriage 12 in the lower end position is arranged so far below the sea surface 4 at both low and high tide that the boat 9 can pass over the carriage 12, i.e. the draft of the boat 9 is less than the distance between the top of the carriage 12 and the sea surface 4 at low or high tide.

[0043] The lifting and lowering device 8 has two arms 14 and 16: one arm 14 that leads into a lifting direction H and one arm 16 that trails behind it. The terms "leading" and "trailing" are used here in relation to the lifting process. When the lifting and lowering device 8 is lowered in the lowering direction, the designations of the arms 14 and 16 remain the same. Both the leading arm 14 and the trailing arm 16 are rigid, non-moving structures. The leading arm 14 and the trailing arm 16 are arranged to be movable relative to each other.

[0044] In the Fig. 1. The boat 9 has moved over the sled 12 and is resting on the sled 12, and the lifting process has just begun.

[0045] In Fig. Figure 2 shows the lifting and lowering device 8 in a perspective view. The leading arm 14 is the upper arm, and the trailing arm 16 is the lower arm. The boat 9 has already been lifted a short distance out of the sea. The lifting and lowering device 8 is in an intermediate position between its upper and lower end positions. The boat 9 rests on the carriage 12. The carriage 12 is surrounded laterally by fenders, which prevent the boat 9 from being struck by the leading arm 14 as it moves onto the carriage 12 and protect the boat's hull.

[0046] Both the leading arm 14 and the trailing arm 16 are formed from a lattice framework. Other embodiments are of course conceivable.

[0047] Fig. Figure 2 shows that four boats 9 are already arranged on deck 11 of the offshore platform 1 and a fifth boat 9 is currently being lifted. After the lifting and lowering device 8 has reached its upper end position, the boats 9 are pulled off the carriage 12 by means of a (not shown) sliding device and then moved laterally by means of another sliding device to make room for another boat 9.

[0048] Fig. 3 shows the in Fig. Figure 2 shows the lifting and lowering device 8 in a view from a low angle. The lifting and lowering device 8 is shown in its upper end position. The leading arm 14 has two lateral arms 14a, 14b, the distance between which is such that the trailing arm 16, at least in its upper end position, fits between the two lateral arms 14a, 14b and is positioned between them. The distance between the lateral arms 14a, 14b is greater than the width of the trailing arm 16.

[0049] Both the leading arm 14 and the trailing arm 16 are angled. They each have a platform-side section and a platform-remote section. The platform-remote section projects at an angle in the lifting direction H from a platform-side leg. The angle between the platform-side and platform-remote sections is 90°. However, it can also have other angle values, preferably 90° ± 10°, but also any intermediate value, or even larger or smaller values. Both the leading arm 14 and the trailing arm 16 are articulated to the slewing ring 13 offset from each other in the lifting direction H. Each of the two arms 14, 16 is articulated to the slewing ring 13 by at least two joints.

[0050] Fig.Figure 4 shows the attachment of the arms 14, 16 to the slewing ring 13. A circular disc is provided on the slewing ring 13, from which laterally and downwardly projecting brackets 15 extend, to which the leading arm 14 is articulated, and downwardly projecting brackets 17 extend, to which the trailing arm 16 is articulated.

[0051] Furthermore, both the leading arm 14 and the trailing arm 16 are articulated to the carriage 12. The carriage 12 has leading spacers 18 and trailing spacers 19 projecting from the seabed side. The leading arm 14 is articulated to the leading spacers 18, and the trailing arm 16 is articulated to the trailing spacers 19.

[0052] An offset of the pivot points of leading to trailing arm 14, 16 on the carriage 12 in a longitudinal direction L corresponds to the offset of the pivot points of leading to trailing arm 14, 16 in longitudinal direction L on the slewing ring 13. The leading arm 14 has an end section that projects perpendicularly from the seabed-side section towards the seabed 3.

[0053] The leading arm 14 has two lateral arms 14a, 14a, which extend from a common platform-side section of the leading arm 14 and are spaced sufficiently apart to allow the carriage 12 to pivot between them. The two arms 14, 16 are coupled to each other by the articulated connection to the slewing ring 13 as well as by the articulated connection to the carriage 12 such that, during both a lifting and a lowering movement, the carriage 12 maintains its angular position relative to the sea surface 4 in every position, i.e., it is always arranged almost horizontally to the sea surface 4. This makes it possible to raise or lower the boat 9 while keeping the boat 9 constantly horizontally oriented. Reference symbol list 1 Offshore platform 2 3 Support legs seabed 4 Sea surface 4a Sea 6 Platform edge 7 Underside 8 Lifting and lowering device 9 Boat 11 Deck 12 sleds 13 Turntable 14 advancing arm 14a lateral arm 14b lateral arm 15 leading brackets 16 trailing arm 17 trailing brackets 18 leading spacers 19 trailing spacers H Hearing correction L Longitudinal direction

Claims

[1] Offshore platform with a lifting and lowering device (8) with a carriage for receiving a boat (9) and with at least two angled arms (14, 16) which are offset in the direction of a pivoting movement on an underside (7) of a platform facing a sea surface (4) and in the same manner on the carriage (12) and pivot the carriage (12) from a lowered position below the sea surface (4) to a raised position at the level of an upper surface (11) of the platform and during the pivoting movement hold the carriage (12) at the same angle to the sea surface (4), characterized by , that the lifting and lowering device (8) is rotatably arranged on the underside (7) on a slewing ring (13). [2] Offshore platform according to claim 1, characterized by, that the arms (14, 16) each have a platform-side section that is longer than a distance between the pivot point on the underside (7) of the platform and a platform edge (6) and the arms (14, 16) each have a seabed-side section that is longer than a distance between the underside (7) and the top (11) of the platform. [3] Offshore platform according to claim 1 or 2, characterized by , that each of the arms (14, 16) has two pivot points on the sled (12) on opposite longitudinal sides. [4] Offshore platform according to claim 1, 2 or 3, characterized by , that the platform-side section and the seabed-side section of the arms (14, 16) are arranged at an angle of 90°±10° to each other. [5] Offshore platform according to any one of claims 1 to 4, characterized by, that a first cylinder is connected at one end to the underside (7) of the platform and at another end to the arm (14) which moves forward during the lifting movement. [6] Offshore platform according to any of the preceding claims, characterized by , that a second cylinder is connected at one end to the trailing arm (16) and at the other end to the leading arm (14). [7] Offshore platform according to any of the preceding claims, characterized by , that the arm (14) advancing into a lifting direction (H) has two lateral arms (14a, 14b) arranged laterally on the carriage (12) and spaced apart from each other, the distance between which is greater than a width of the trailing arm (16). [8] Offshore platform according to any of the preceding claims, characterized by, that a sliding device is provided on the top (11) with which the boat (9) can be moved from the top (11) onto the slide (12) and from the slide (12) onto the top (11). [9] Offshore platform according to any of the preceding claims, characterized by , that the leading and trailing arms (14, 16) are articulated to spacers (18, 19) arranged on a seabed-facing underside of the sled (12).

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