Technical field

[0001 ] The present invention relates generally to system for transporting objects to ocean structures.

Background art

[0002] Due to the incidence of accidents there are strict limitations regarding acceptable sea conditions when boarding or transporting objects to an ocean structure such as for example an offshore oil or wind energy platform. This limits the time window for maintenance and repair.

[0003] These are well-known problems and dangers within the industry, both when transferring personnel, equipment and supplies to or from an ocean structure. The same problem also arises when boarding a larger ship from a smaller boat.

[0004] To overcome these limitations boats are getting bigger and more

sophisticated and the costs of equipment, personnel and fuel, are increasing. The use of bigger boats have created new problems that can occur when the boats accidentally collides into the platform/foundation structure. If the

platform/foundation structure and/or its corrosion protection are damaged the consequences are severe.

[0005] Known boarding solutions are for example hanging transport baskets, wave compensated gangways or cranes mounted on the boat transporting the personnel or equipment to the ocean structure.

[0006] It is also known to use boat lifts for use with ocean structures including one or more mount components for attaching to side regions of a boat. One or more mechanisms are coupling between the one or more mount components and the structure for operatively lifting up or down the mount components relative to the structure. Such boat lift is known from GB2479742 A. [0007] A drawback with this systems is that the mechanisms, in the form of upright members, are welded or otherwise affixed to the ocean structure by a plurality of connection points between the upright members and the structure forming a rigid connection. A further drawback with such system is that it comprises many components which makes it expensive both to manufacture, as well as install and/or replace on the ocean structure.

Summary of invention

[0008] An object of the present invention is to provide a system for transporting objects to ocean structures which prevents personal injuries and reduces the risk of damage to the boat/equipment transported to the structure or the structure itself.

[0009] A further object of the present invention is to provide a system for transporting objects to ocean structures which is stable yet less susceptible to bending forces. The bending forces may cause damage to the structure due to wear as a result of prolonged use, which in turn increases the risk for operators or crew members.

[0010] A further object of the present invention is to provide a system for transporting objects to offshore structures which are cost effective to manufacture and install as well as replace.

[001 1 ] According to one embodiment the invention provide a system for transporting object from a sea level position to an elevated position on a structure, wherein the sea level position is movable in relation to the elevated position. The system comprises; an elongated guide device configured to be arranged to the structure in one end and to extend below the sea level with a second end, an attachment device configured to be arranged on said object and for attaching said object to the elongated guide device, wherein the attachment device is configured to allow a relative movement between the attachment device and the elongated guide device along a first direction parallel to the extension direction of the guide device, and to restrict movement along a direction perpendicular to the first direction, a lifting device configured to transport the object from the sea level position to the elevated position ,

The system is characterized in that a weight is arranged to the second end of the guide device below the sea level for stabilizing the guide device, wherein the second end is a free end and the weight is a free weight.

[0012] The mass of the weight, the position of the weight and second end of the guide device sufficiently submerged below the sea level provides a stable guide device adapted to be used for lifting heavy objects, at the same time as it does not have to take up as high bending forces. The attachment device allow a movement along one first direction and restrict movement in a direction essentially

perpendicular to the first direction. However, a play between attachment device and guide device may be present, allowing a limited movement in the direction essentially perpendicular to the first direction. Further, with a system constructed according to this embodiment, where the guide device has a free end with a weight for stabilizing the device, the guide device is able to pivot around its attachment point to the structure and hence move slightly relative the structure. Thus, the guide device withstands less bending forces on the respective parts than the previously known transport and boarding structures with a fixed guide member. Thus, such a system is not as susceptible to wear, will have a longer life span and require less service than the previous known solutions. Further, with a free weight attached in one end of a guide device it is possible to move the transport system away from the structure and to lift the objects at a certain distance from the structure, thus minimizing the risk of collision between the structure and object to be lifted during the vertical transportation. Further, the system is cheap to manufacture since it comprises few parts, a majority of which are standard parts, as well as being cheap to install as well as replace when necessary. [0013] According to one embodiment the attachment device is configured for guiding the object from the sea level position to the elevated position along the elongated guide device when transported by the lifting device.

[0014] To use a separate lifting device to transport the object and only use the attachment devices for guiding the object during the vertical movement is a more reliable solution than previous known art. Further, it is possible to use lifting devices already present at the structure and thus to create a more cost efficient solution.

[0015] According to one embodiment the weight is arranged to the second end of the guide device at a position at least 5m below sea level, preferably at least 10m below sea level, whereby the guide device is unaffected by motions of the sea.

[0016] When arranging the weight a certain distance below sea level, the transporting procedure is simplified since the guide device is kept straight and stretched and stay unaffected of rough seas. The distance below sea level depend on the conditions present at the site where the structure is located. The weight shall be arranged at a depth unaffected by waves and sea current but shall hang free and not be attached to or rest on the bottom of the sea.

[0017] According to one embodiment the guide device comprises two parallel arranged guide wires having a distance from each other. Said guide wires are in one embodiment made of steel.

[0018] Using two parallel arranged guide wires enables two attachment points to the object to be transported. Thus, it enables hoisting of the object without the object rotating and swinging. It is also easier to keep the object horizontal during lifting.

[0019] According to one embodiment the distance between the guide wires is kept constant by a beam extending between the guide wires or wherein the weight is made in one piece and extend between the guide wires. [0020] A constant distance between the guide wires simplifies the attachment procedure when the object is docked to the guide device.

[0021 ] According to one embodiment, the attachment device comprises a first and a second attachment device part arranged to grip the respective guide wires.

[0022] When separating the attachment device in two attachment device parts it is possible to arrange the different parts on suitable positions on the object to be transported. I.e. the attachment device parts may for example be placed on opposite sides of a stern or stem if the object is a boat or vessel. If more than one object is to be attached to the guide device at the same time, for example a boat and a container where only the container is to be lifted, it is preferred that the respective attachment device parts are arranged at the respective object so that it is possible to attach the objects on different horizontal levels.

[0023] According to one embodiment, the weight comprises two separate blocks connected by a beam. According to one embodiment, the weight has a mass of 3- 10 tons.

[0024] A weight having this specific mass is complicated to transport out to the structure at sea. It is therefore an advantage if the weight can be made or assembled at the structure. A weight comprising several parts is easier to handle and transport. The weight of the mass is dependent on the type and weight of the object to be transported. It may also be chosen to be above a certain mass so that it stays essentially unaffected by motions of the sea.

[0025] According to one embodiment, the structure comprises beams or davits extending from the structure, wherein the first end of the guide device is

configured to be arranged to the beams or davits.

[0026] When using beam or davits extending from the structure it is possible to lift the objects at a further distance from the structure, thus further minimizing the risk of collision between the structure and object to be lifted during the vertical transportation. [0027] According to one embodiment a traverse system is arranged on said structure configured to transport the object in a direction essentially perpendicular to the first direction when the object is in the elevated position.

[0028] When the objects has been lifted to the elevated position by the lifting device the traverse system may be used to transport the object to a place in the structure more protected from the weather and the open ocean.

[0029] According to one embodiment, the lifting device is a crane or a winch, arranged on the structure or configured to be arranged on or connected with the object.

[0030] According to one embodiment, the object is a container, equipment, person transporting arrangement, ship or vessel.

[0031 ] According to one embodiment, the structure is an ocean based platform, or another vessel or ship.

[0032] According to one embodiment, the weight is configured to be moveable from its position below the sea level to an elevated position above sea level.

[0033] In one embodiment the weight is also moveable in a direction essentially perpendicular to the first vertical lifting direction, when the weight is in the elevated position. When the weight is moveable it is possible to store both the object and/or the weight when no transportation to or from the structure is needed.

Brief description of drawings

[0034] The invention is now described, by way of example, with reference to the accompanying drawings, in which:

[0035] Fig.1 a shows a side view of a system according to a first embodiment of the invention, wherein a first type object, a boat, is arranged at sea level position and a second type object, a container, equipment or person transporting arrangement is transported in a first vertical direction from the first type object to an elevated position of the structure. [0036] Fig. 1 b shows another side view of a system according to Fig. 1 a.

[0037] Fig. 2a shows a side view of a system according to another embodiment of the invention, wherein a first type object, a boat, is arranged at sea level position and the first type object is transported from sea level position to an elevated position of the structure.

[0038] Fig. 2b shows another side view of a system according to Fig. 2a.

[0039] Fig. 3a shows a side view of a system according to another embodiment of the invention, wherein a first type object, a boat, and a weight is transported in a first vertical direction from a sea level position to an elevated position.

[0040] Fig 3b shows another side view of the system according to fig. 3a, wherein the first type object and the weight is transported in a second direction, perpendicular to the first direction.

[0041 ] Fig 3c shows a bird view of the system according to fig. 3a and 3b.

[0042] Fig. 4 shows an attachment device comprising a first and second attachment device parts attached to an object.

[0043] Fig. 5a-5c shows an attachment device in different positions.

Description of embodiments

[0044] In the following, a detailed description of the invention will be given. In the drawing figures, like reference numerals designate identical or corresponding elements throughout the several figures. It will be appreciated that these figures are for illustration only and are not in any way restricting the scope of the invention.

[0045] Fig. 1 a shows a side view of a system 1 according to the invention, wherein an object 2 in the form of a boat 2b, transporting another object 2 in the form of a container, equipment or person transporting arrangement 2a, is arranged in a first position in relation to the system 1 . In the first position, the stem of the boat 2b is pointing towards a structure 3. It is of course also possible, but not shown, to direct the stern towards the structure 3. Fig. 1 b shows the Fig 1 a from another side, i.e. showing a rear view of the objects 2a, 2b. The structure 3 is in this embodiment an ocean based offshore platform. According to another embodiment, the structure 3 is another vessel or ship essentially larger than the transport boat 2b.

[0046] Fig. 1 a and 1 b further shows a system 1 for transporting objects, such as e.g. container, equipment or person transporting arrangement 2a or boats or vessels 2b from a sea level position A1 to an elevated position B on a structure 3 wherein the sea level position A1 is movable in relation to the elevated position B. The relative movement of the sea level position A1 and the elevated position B is due to the movement of the sea itself, i.e. due to waves, currents or similar, in relation to the rigid structure 3. A sea level position A1 is a position which is affected by the movement of the sea, thus, the position may be at the actual sea level AO if the object is a boat, or alternatively both above and below the sea level if the object is a container or equipment.

[0047] According to one embodiment, the system 1 comprises a guide device 4 configured for guiding an object 2a, 2b from the sea level position A1 to the elevated position B along a first direction parallel to the extension direction of the guide device 4, i.e. between the sea level position A1 and the elevated position B. The guide device 4 is configured to be arranged to the structure 3 in one end and to extend below the sea level AO with a second end. According to one

embodiment, the first direction is a vertical direction y. According to one

embodiment, shown in figure 1 b, the guide device 4 comprises two parallel arranged guide wires 4a, 4b having a distance from each other. The guide wires 4a, 4b may be made of steel. According to one embodiment, the wires have a diameter of 60-90mm preferable 70-80mm, most preferably 76mm. According to one embodiment, the guide device 4 is 20-50 m long. According to one

embodiment, the guide device 4 is 30-40m long. According to one embodiment, the distance between the guide wires 4a, 4b may be kept constant by a beam 4c extending between the guide wires 4a, 4b. Alternatively, the distance between the guide wires 4a, 4b is adjustable by means of distance adjusting device which may comprise a telescopic beam or other length adjustable solution. The beam may be a metal beam. The distance between the guide wires may be determined by the size of the object to be transported.

[0048] According to one embodiment, the guide device 4 is attached to the structure 3 at a fixation point. This point is located above sea level AO, preferably above the elevated position B. The structure may comprise beams or davits 3a extending from the structure 3, wherein the first end of the guide device 4 is configured to be arranged to the beams or davits. The end of the guide device 4 may not be the actual end of the guide wires 4a, 4b or other embodiments of the guide device 4, however, the fixation point of the guide device 4 in the structure 3 defines the end of the guide device 4. In one preferred embodiment, the guide device is pivotably or rotatably attached to the structure in the fixation point. I.e. the attachment allow some relative movement between the guide device 4 and structure 3.

[0049] The system 1 further comprises an attachment device 5 configured to be arranged on the object 2a, 2b and for attaching the object 2a, 2b to the guide device 4. The attachment device 5 is configured to allow a relative movement of the attachment device 5 and the guide device 4 along the first direction between the sea level position and the elevated position, and to restrict movement along a direction perpendicular to the first direction but still allowing a small play between the attachment device and guide device. According to one embodiment, the attachment device 5 is fixedly arranged on the object 2a, 2b. According to one embodiment the attachment device 5 comprises a first and second attachment device part 5', 5" arranged to grip the respective guide wire 4a, 4b. The

attachment device 5 is further described in figure 4a-4c.

[0050] The system further comprises a lifting device 8 configured to lift the object 2a, 2b along the guide device 4 the first direction between the sea level position and the elevated position. According to one embodiment, the lifting device 6 is a crane or a winch (not shown), arranged on the structure 3. According to one embodiment, the lifting device 8 is arranged on the object 2a, 2b itself and configured to interact with the structure 3 such that a relative movement between the object 2a, 2b and the structure 3 can be generated. For example, a winch or similar may be arranged on the object 2a, 2b wherein a wire 8a extending from the winch may be arranged in or guided via a position in the structure 3, which is located at a point near the elevated position. The fastening point for the wire may thus be on the object 2a, 2b itself if there is a guiding point in the structure 3. Upon activating the winch, the object is pulled from the sea level position towards the elevated position. When the object 2a, 2b reaches the elevated position B it can be attached to fixed straps or other objects. This will enable the lifting device 8 to be released and used to move other items.

[0051 ] The system further comprises a weight 6 which is arranged to the second end of the guide device 4 below the sea level for stabilizing the guide device 4. Hence, the second end of the guide device 4 is a free end and the weight 6 is a free weight, in that the weight 6 itself is connected only to the second end of the guide device 4 and that the second end of the guide device 4 is connected only to the weight 6. Thus, the free end and free weight is slightly moveable with the structure and ocean currents in all directions in space. However, the weight is chosen to have a mass so heavy that the free weight and free end is kept essentially stationary in the water. According to one embodiment, the weight 6 has a mass of 3-10 tons, preferably 5-7 tons, most preferably 6 tons. However, other masses are also possible since the weight is also dependent on the type and weight of the object to be transported. According to one embodiment, there is no further connection points to the guide device 4 between the first end and the second end of the guide device 4. As a result, the guide device 4, especially when in the form of two guide wires 4a, 4b, are kept stretched by the weight 6 attached at their second ends. According to one embodiment, the length of the guide device 4 is such that the weight is arranged to the second end of the guide device 4 at a position at least 5m below sea level, preferably at least 10m below sea level, whereby the guide device 4 is unaffected by motions of the sea. According to one embodiment, the weight 6 comprises two separate blocks 6a, 6b connected by a beam, e.g. a steel beam. The respective block may then be connected to a respective guide wire 4a, 4b. The beam further aids to keep the guide wires 4a, 4b at a constant distance from each other. According to another embodiment the weight 6 is made in one piece as a single unit and extend between the guide wires 4a, 4b to keep the distance between the guide wires constant.

[0052] According to one embodiment, both the object 2a, i.e. the container or equipment to be transported as well as the boat 2b may be attached to the guide device 4. I.e. one attachment device 5 may be arranged on each object in order to guide both objects when lifted or to moveably attach the second type object 2b, a boat, to the structure when a second type object 2a, a container or similar, is guided by the guide device towards the elevated position. If more than one object is to be attached to the guide device at the same time, for example a boat and a container where only the container is to be lifted, it is preferred that the respective attachment device are arranged at the respective object so that it is possible to attach the objects on different horizontal levels.

[0053] Fig. 2a shows a side view of a system according to the invention and fig. 2b shows a rear view of the system, wherein the object 2 is a boat or vessel 2b. The boat or vessel 2b is disclosed in a first position at sea level A1 an when lifted a certain distance along the guide device 4 in a first, vertical direction from the sea level position A1 towards the elevated second position B of the structure 3. The sea level position A1 is in this embodiment the actual sea level AO since the object is a boat. The boat is arranged in relation to the system 1 so that a side of the boat 2b is arranged facing the guide device 4. The boat 2b is flexible attached, in vertical direction, to the guide wires 4a, 4b of the guide device 4 by help of the attachment device 5 which is fixed to the boat 2b. The attachment device 5 comprises a first and second attachment device part 5a, 5b arranged to grip the respective guide wire 4a, 4b. In order for the boat 3b to have a free transportation way, the guide wires 4a, 4b are attached in one end to beams or davits 3a extending from the structure 3. The guide wires 4a, 4b are in their other end attached to the weight 6. The connection of the boat 2b to the guide wires 4a, 4b enables hoisting of the boat without the boat rotating and swinging. By help of a lifting device 8 placed on a platform on the structure 3 and a wire 8a extending from the lifting device 8 to the boat 2b, the boat is transported from the sea level to the elevated position. When the boat is in the elevated position, persons or equipment may safely be embarked from the boat to the structure without risking injury. When in its elevated position it is also possible to release the boat 2b from the lifting device and secure it to the structure with other means, for example davits. It is the possible to use the lifting device 8 for other purposes.

[0054] Fig 3a, 3b and 3c shows another embodiment of the system according to the invention. In this embodiment the weight 6 is configured to be vertically moveable from its position below the sea level to an elevated position B2 above sea level in a first direction y. The elevated position B2 is in this embodiment essentially the elevated position B, but any other elevated position is possible. At least one winch 9 or other type of lifting device is arranged to move said weight 6 by hoisting the guide wires 4a, 4b. In one embodiment the weight is lifted a time period after the object is lifted. In some conditions it is also possible to lift the weight simultaneously with the object.

[0055] In one embodiment a traverse system 1 1 is arranged on the structure 3. The traverse system 1 1 may comprise one or more horizontally arranged beams 1 1 a extending from the structure 3. The traverse system 1 1 is configured to transport the object, i.e the boat and/or equipment 2a, 2b in a direction x essentially perpendicular to the first vertical lifting direction y when the object 2a, 2b is in the elevated position B. I.e. when the boat and/or equipment has been lifted to the elevated position by the lifting device 8 it can be transported to a place in the structure 3 more protected from the weather and open ocean. In one embodiment the weight 6 is also moveable in a direction x essentially

perpendicular to the first vertical lifting direction y, when the weight is in the elevated position B2. The object 2a, 2b and/or the weight 6 is thus safely stored when no transportation to or from the structure 3 is needed. The wires 4a, 4b attached to the weight 6 and the wire 8a attached to the object to be lifted 2a, 2b may run in a system of blocks and tackles 1 1 b to optimize the lifting capacity of the system and to enable the horizontal movement. Both the guide device 4 and the lifting wire 8a may, in one embodiment, be attached to a single structure 1 1 a moveable in the horizontal direction. Thus, when both the boat 2b and the weight 6 is in the elevated position B2, the single structure 1 1 c is moved horizontally. In one embodiment, the single structure 1 1 a is fixed in relation to the transverse system 1 1 and the entire transverse system 1 1 comprising beams is moved horizontally in the x-direction by a movement device of any kind.

[0056] Figure 4 disclose an embodiment of the attachment device 5. The attachment device 5 comprises a first and second attachment device part 5', 5" arranged to grip the respective guide wires 4a, 4b of the guide device 4. The respective attachment device part 5', 5" are attached to the object 2a, 2b with a distance adapted to the distance between the guide wires 4a, 4b. When the object 2a, 2b is docked to the guide device 4, the respective attachment device part 5', 5" catches the guide device and partly grip the respective wire 4a, 4b.

[0057] According to one embodiment, shown in figures 5a-5c, the attachment device 5 comprises a hook or openable ring 5b arranged in a housing 5a. The hook 5b is rotatable around a first end by a rotation device 5c for releasable attaching the attachment device 5 around the guide device 4 in the form of e.g. guide wires 4a, 4b.

[0058] Figure 5a-c shows the hook 5b in a first, second and third position. In the first position, figure 5a, the hook is stored away. In the second position, figure 5b, the hook is rotated so that it easily catches the guide device and partly grip the respective wire 4a, 4b. In the third position, figure 5c, the hook is in its locked position where a relative movement in a first direction, i.e. a vertical lifting direction, is allowed and a movement perpendicular to the first direction is restricted. Within the meaning of a restricted movement, a certain limited movement may be allowed due to variations or slight differences between the guide wire diameter and the diameter of the hook or openable ring. A restricted movement may also be an entirely restricted movement, i.e. wherein no relative movement is allowed and the hook or openable ring is locked in relation to the guide wires 4. [0059] A preferred embodiment of a system for transporting objects from a sea level position to an elevated position according to the invention has been described. However, the person skilled in the art realizes that this can be varied within the scope of the appended claims without departing from the inventive idea It is of course also possible to use the same system for transporting objects from an elevated position to a sea level position.

[0060] All the described alternative embodiments above or parts of an embodiment can be freely combined without departing from the inventive idea as long as the combination is not contradictory.