The present invention relates to a system for transferring crew, personnel, goods and equipment between a vessel and a floating structure, for example an offshore structure or another vessel, where the system comprises a ladder arranged on the vessel and a landing platform for the ladder, which landing platform is arranged on the floating structure. The present invention also relates to a method for transferring crew, personnel, goods and equipment between a vessel and a floating structure.

Transfer of crew, personnel, goods and equipment between floating structures, for example between a vessel and an offshore structure, or between two vessels, can be extremely dangerous, particularly on account of the relative movement between the floating structures. Crew and personnel often have to be transferred from a relatively small vessel, which vessel is influenced by waves, currents and/or wind, over to vertical steps mounted on the floating structure to which they are to be transferred. In these circumstances it is easy, not only for untrained and inexperienced crew members and personnel, but also for those who have undergone training for an operation of this kind, to slip or stumble during the transfer, with the result that the crew and personnel may be injured and/or fall into the water. For this reason existing safety regulations have restricted transfer of crew and personnel offshore to relatively calm conditions, usually where the significant wave height is less than 1.5 metres. As a result of this, significant working hours can be lost due to bad and unfavourable weather, leading to substantial additional costs in connection with such operations for companies operating offshore.

At present several known systems exist for transfer of crew and personnel between a vessel and an offshore structure, where a ladder is employed for transferring the crew and the personnel between the vessel and the offshore structure. According to the known solutions the ladder will be attached or secured to the offshore structure by means of a claw or the like. The solution requires the ladder to follow the vessel's and/or the offshore structure's movements to a far greater extent. This means that the ladder has to be of a more robust design (oversized) and/or that the vessel is equipped with dynamic positioning equipment. This will provide an expensive and complicated solution, which in addition can only stand a limited wave motion.

A system is also known where a ladder is controlled from the vessel and is stabilised by means of a so-called gyro-controlled system. This will not provide a satisfactory solution either, since it is expensive and has a limited area of application. An object of the present invention will therefore be to attempt to solve some of the above-mentioned problems or drawbacks, as well as providing a safe system for transferring crew, personnel, goods and equipment in the marine environment.

Another object according to the present invention will be to provide a system which attempts to minimise the effect of the relative movement between the floating structures, in order thereby to permit transfer of crew, personnel, goods and equipment within a greater range of different sea states.

A further object of the present invention will be to provide a user-friendly and safe link between a ladder arranged on a vessel and a landing platform arranged on a floating structure.

Yet another object of the present invention will be to provide a simple and uncomplicated system for transferring crew, personnel, goods and equipment between a vessel and a floating structure.

These objects are achieved with a system and a method for transferring crew, personnel, goods and equipment between a vessel and a floating structure as indicated in the following independent claims, where further features of the invention will become apparent from the dependent claims and the description below.

The present invention relates to a system for transferring crew, personnel, goods and equipment between two floating structures, for example between a vessel and an offshore structure or between two vessels, where a ladder forms the link between the two floating structures. The ladder will be arranged on one of the floating structures, for example the vessel, while a landing platform will be arranged on the other floating structure, for example the offshore structure. The ladder is designed to be telescopic, whereby the ladder will be composed of at least two sections which are interconnected in a suitable manner. In order for the system according to the present invention to be able to be used safely within a greater range of different sea states, one end of the telescopic ladder is "freely" mounted to the vessel. The mounting is preferably implemented via a universal joint, which universal joint permits the telescopic ladder to be moved "freely" in all directions about the universal joint. The other end of the telescopic ladder, i.e. the end opposite the connection with the vessel, is provided with an outwardly protruding element, a "tongue" or the like, which outwardly protruding element is arranged to cooperate with an opening or receiving pocket in the landing platform which is connected to the offshore structure. Alternatively, the telescopic ladder's outwardly protruding element may be provided with an opening or receiving pocket for receiving a "tongue", in which case the "tongue" will be provided in the landing platform.

The opening or receiving pocket may furthermore be designed so as to prevent a rotation of the telescopic ladder about its longitudinal direction, but permit lateral and/or up-and-down movement.

The landing platform, which, as an example, is arranged on a offshore structure, comprises a towing rope or hauling line arrangement and an associated retriever line arrangement, where the towing rope or hauling line arrangement is composed of at least one towing rope or hauling line, which the at least one towing rope or hauling line, besides providing a link between the vessel and the offshore structure, also serves the purpose of facilitating the process of connecting the telescopic ladder with the offshore structure. The towing rope or hauling line arrangement will furthermore be designed so that the towing rope or the hauling line will automatically be coiled up in a coiling up arrangement when not in use. In order to prevent the towing rope or the hauling line from being completely coiled up, a stopper device, for example in the form of a disc or plate, is provided at a distance from the free end of the towing rope or hauling line. When the disc or plate "hits" the towing rope or hauling line arrangement, the towing rope or hauling line will be prevented from coiling up further. In a free end of the towing rope or hauling line is arranged a retriever line, where the retriever line, when the towing rope or hauling line is coiled up, will hang from the end of the towing rope or hauling line and down in the sea. The retriever line is used by the vessels crew to pull out the towing rope or hauling line, where this is achieved by use of an auxiliary winch arranged on the vessel. The retriever line is stabilized by that a weight or lead is placed in its free end, thereby causing the retriever line to be suspended tautly when not in use.

It should be understood that the number of towing ropes or hauling lines used in the towing rope or hauling line arrangement may vary, depending on the size of the size of the floating structure(s), the loads to which the system is exposed, the area in which the system is employed, etc.

The actual towing rope or hauling line arrangement may be mounted in the landing platform or adjacent thereto.

On the vessel, on which the telescopic ladder is arranged, in the area near the telescopic ladder's mounting (the universal joint), a fixing and securing arrangement will be provided for at least one towing rope or hauling line, thereby securing the at least one towing rope or hauling line during the transfer operation. Thus the fixing and securing arrangement for at least one towing rope or hauling line will preferably be provided substantially in the same plane as the universal joint, with the result that the telescopic ladder and at least one towing rope or hauling line will be located in the same plane during the entire transfer operation. The vessel will then be connected to the telescopic ladder via the universal joint and the telescopic ladder will further be connected to the landing platform via the at least one towing rope or hauling line. The landing platform may furthermore be fixedly connected to the offshore structure, in which case the landing platform may be designed to be able to swivel out to both sides from a starting position, for example 60 degrees to each side. This may be achieved, for example, by using a hinge device or a rotatable joint. This embodiment will permit the landing platform to follow the vessel's orientation into wind and weather.

In an alternative embodiment the landing platform is movably connected to the offshore structure via a framework. The framework will then extend round the entire circumference of the structure, thereby permitting the landing platform to be moved around 360 degrees. In some cases it may also be appropriate to use more than one landing platform on an offshore structure, particularly if the landing platform is fixedly connected to the offshore structure. The landing platforms will then be arranged at a distance apart, thereby enabling the vessel to be connected to the landing platform which is most favourably located with regard to wind and weather conditions. When the vessel is connected to the landing platform through the at least the one towing rope or line, the vessel will back away from the offshore structure (the vessel will then be in towing mode), whereby the towing rope(s) or line(s) which are connected to the vessel then will be tightened up with a force corresponding to which the vessel is backing with. The at least one towing rope or line is then dimensioned in order to be able to take up all of the vessels tractive power. When the at least one towing rope or line has been sufficiently tightened up, the telescopic ladder can use the at least one towing rope or line as a support and guide path when the ladder is pushed out from the vessel towards the offshore structure. The outermost section of the telescopic ladder will then be provided with guide devices for the at least one towing rope or line, thereby facilitating the guiding and support process of the telescopic ladder.

The system according to the present invention will permit the vessel to be moored to the offshore structure during the entire transfer process. In addition, by backing out from the offshore structure, the vessel will keep the at least one towing rope or line taut all the time. The telescopic ladder, which now, in practice, is tensioned between the vessel and the landing platform, uses an arrangement for insertion and withdrawal of the ladder's sections, such that it is exerted a continuous compressive force against the landing platform during the connection with the landing platform. Through the arrangement for insertion and withdrawal of the telescopic ladders sections, the outermost section will be pushed outwards towards the landing platform, and at the same time exert a continuous press force against the landing platform, and also give off if the vessel should approach the landing platform. The system according to the present invention is thus based on that the vessel during the connection with the landing platform all the time back away from the offshore structure, and essentially will keep a fixed distance from the offshore structure. The flexibility (elasticity) in the towing rope or line will mainly make the dampening in the system.

The telescopic ladder is preferably mounted on a vessel's deck, where the telescopic ladder can be directly and permanently connected to the vessel via a universal joint, or else the telescopic ladder may be connected to a movable carriage or the like, where the movable carriage is further connected to a rail system on the deck.

In its simplest form the telescopic ladder may be in the form of a footbridge, possibly also with a handrail, but is preferably designed as a protected area. In this case the telescopic ladder will be provided with side walls and ceiling. The side walls may furthermore be provided with a plurality of openings or windows, through which crew and personnel have a clear view.

The telescoping (insertion and withdrawal) of the telescopic ladder's are ensured by use of a rail and wheel system. For insertion and withdrawal of the telescopic ladder's sections, and also maintenance of the continuous press force, it can be used an arrangement with one or more electrical servomotors, or also a hydraulic, pneumatic, spring or winch arrangement. The arrangement is then of such a nature that it will always exert a force (press force) on one or more of the ladders sections, but simultaneously give off if the pressure on one or more of the sections become to large. How this arrangement should be designed and connected to the telescopic ladder will be known to a person skilled in the art and will thus not be discussed further here.

When the system for transferring crew, personnel, goods and equipment according to the present invention has to be employed for establishing a link between two floating structures, for example between a vessel and an offshore structure, the vessel housing the telescopic ladder will be positioned close to the offshore structure. The at least one retriever line is then fished up by means of a "fishing rod" and is pulled in against the vessel by means of a winch arrangement, as an example. The retriever line will then be guided through various guiding means or the like on the telescopic ladder and thereafter guided to the holding point for the at least one towing rope or line. When the retriever line is pulled in by means of the winch arrangement, the towing rope will be pulled in from the landing platform, via guiding means on the telescopic ladder and in at the fixing and securing arrangement. The fixing and securing arrangement is, as mentioned earlier, arranged in the vicinity of the telescopic ladder's mounting on the vessel. When this is accomplished, the vessel will be connected to the offshore structure via the at least one towing line or line. The vessel will then be headed into the wind and weather and backed away from the offshore structure until the towing rope(s) or line(s) is tightened. The vessel will reverse during the entire transfer operation, in order thereby to keep the towing rope(s) or line(s) substantially continuously taut. An operator will then operate the telescopic ladder's insertion and withdrawal arrangement, whereby the telescopic ladder through the sections is pushed out against the offshore structure. Since the at least one towing rope or line is guided by at least one device in the telescopic ladder's outermost section (i.e. the section that is nearest the offshore structure), the at least one towing rope or line will be guiding and supporting the ladder. Finally the telescopic ladder will be pushed so far out that the telescopic ladder is brought into engagement with the opening or the receiving pocket in the landing platform. The insertion and withdrawal arrangement, due to the continuous exerting press force on the telescopic ladder, will always ensure that the telescopic ladder is in engagement with the opening or the receiving pocket in the landing platform. The system is now ready for transfer of crew and personnel.

Other advantages and special features of the present invention will become apparent from the following detailed description, the attached drawings and the following claims.

The invention will now be described in more detail with reference to the following figures, in which

Figure 1 illustrates a vessel which has to be connected to a fixed structure offshore, where the vessel has approached the fixed structure,

Figure 2 shows that the vessel is connected to the fixed structure via at least one towing rope or line and where a telescopic ladder is on the way to being connected with a landing platform on the fixed structure,

Figure 3 illustrates the telescopic ladder in a connected position with the landing platform on the fixed offshore structure,

Figure 4 illustrates an embodiment according to the present invention, where a landing platform is arranged to rotate freely round the offshore structure,

Figure 5 illustrates a second embodiment according to the present invention, where the landing platform is fixedly connected to the offshore structure, and Figure 6 illustrates details of the landing platform according to the second embodiment. In figure 1 a vessel 1 is illustrated which has approached an offshore structure 2, to which offshore structure 2 the vessel 1 has to be connected or moored, in order thereby to establish a "bridge connection" between the vessel 1 and the offshore structure 2. The vessel 1 contains a telescopic ladder 3, which telescopic ladder 3 can be rearranged from a retracted and inactive position on the vessel 1 to an extended position connected with the offshore structure 2.

In a preferred embodiment of the present invention the offshore structure 2 is composed of a windmill, a platform, a wave power station or the like, but it is also conceivable for the vessel 1 to be connected with another vessel (not shown). The offshore structure 2 may furthermore be of such a nature that it is located on the seabed, or it may be anchored to the seabed by means of anchor cables or mooring lines, be dynamically positioned or the like.

The telescopic ladder 3 is preferably in the form of a protected foot bridge, comprising side walls and a ceiling and consists of two sections 31, 32, where section 32 is movable internally in the section's 31 longitudinal direction. The telescopic ladder's section 31 is provided with a rail system (not shown) internally along its longitudinal direction. The rails are formed such that they cooperate with a corresponding rail or wheel system in the section 32, whereby the insertion and withdrawal of the section 32 is facilitated. The telescopic ladder 3 further comprises an electric, hydraulic or similar arrangement (not shown), which arrangement is used for moving the telescopic ladder 3 from a retracted and inactive position to an extended and active position and vice versa. The arrangement will furthermore be of such a nature that it will exert a press force on the telescopic ladder all the time, where this press force can be adjusted, thereby enabling an operator on the vessel to determine which press force should be exerted on the at least one section 32 of the telescopic ladder 3 when it is engaged with a landing platform 4 on the offshore structure 2.

The vessel 1 is designed so as to enable the telescopic ladder 3 to be retracted inside the vessel's 1 bow when the telescopic ladder 3 is located in a withdrawn and inactive position.

One end of the telescopic ladder is connected with the vessel 1 via a universal joint (not shown), where the universal joint permits the telescopic ladder 3 to rotate in all directions when in an extended position (sideways, up/down, as well as rotating about the telescopic ladder's 3 longitudinal direction). The telescopic ladder 3 is only connected to the vessel 1 via the universal joint, with the result that the telescopic ladder 3 can be elevated about this connecting point. This will be the case, for example, in figure 1 , where it can be seen that a landing platform 4, which is connected to the offshore structure, is located higher than the telescopic ladder's 3 horizontal storage position. The landing platform 4 on the offshore structure 2 is equipped with a number of towing ropes or lines 5 of predetermined length. The towing ropes or lines 5 are provided at their free end with connecting devices, where these connecting devices cooperate with corresponding fixing and securing arrangement for the towing ropes or lines arranged in the vicinity of the telescopic ladder's mounting with the universal joint. The fixing and securing arrangement on the telescopic ladder will be arranged in same plane as the telescopic ladder's point of rotation (the universal joint) on the vessel. The towing ropes or lines 5 on the landing platform 4 may be connected to a buoy 6 located in the water through a retriever line (help line), such that the retriever line can be "fished" up before it is connected to a pull in mechanism (winch arrangement) on the vessel 1. The towing rope or line will now, by means of the retriever line, be pulled out from the landing platform 4, whereafter the towing rope or line is fastened and secured in the fastening and securing arrangement on the telescopic ladder. The towing rope(s) or the line(s) may be stored in a storage container on the landing platform, or alternatively a gravity-influenced system which pulls the towing ropes or lines in and shields them in vertical tubes 11 (see figure 6) mounted on the landing platform

4 or the fixed structure 2, thereby enabling them to be winched out/in before and after use. Moreover, the landing platform 4 will be provided with an opening 7, where this opening 7 acts as a "receiving pocket" for the telescopic ladder 3. The telescopic ladder 3 will then be provided at its free end, i.e. at the end opposite the universal connection, with an outwardly protruding element ("tongue") 8, where the outwardly protruding element 8 is formed in a complementary manner to the landing platform's 4 opening 7. It should also be understood that this arrangement may be designed in the opposite manner, in which case the landing platform 4 will be provided with an outwardly protruding element (tongue) 8, while the free end of the ladder 3 will be provided with an opening for receiving the outwardly protruding element 8. When only a towing rope 5 is employed, the projecting element 8 will furthermore be in the form of a hollow sleeve, whereby the towing ropes or lines 5 are passed through the outwardly protruding element 8 during connection of the telescopic ladder 3 to the landing platform 4.

The opening 7 in the landing platform 4 will be designed so as to prevent the telescopic ladder 3 from rotating about its longitudinal axis, whereby the telescopic ladder's walkway will substantially remain in a horizontal position. Other movements, such as a lateral and/or a vertical movement of the telescopic ladder 3 will be permitted by the design of the opening 7.

If two or more towing ropes or lines 5 are employed, at least one towing rope or line

5 will be arranged on each side of the outwardly protruding element 8 or along the telescopic ladder 3. This will also substantially safeguard the stability of the telescopic ladder. In a preferred embodiment of the present invention the landing platform 4 is connected via suitable connecting means to a framework 9 extending round the whole structure, thereby permitting the vessel 1 , which is connected to the landing platform 4 via the telescopic ladder 3 and the at least one towing rope or line 5, to head into wind and weather all the time. On account of the framework 9, the landing platform 4 will then be able to rotate 360 degrees around the offshore structure 2, which for example may be a windmill provided with a circular shaft/pillar.

In figure 2 the landing platform's 4 four towing ropes or lines 5 have been fished up from the water or winched out, whereupon the towing ropes or lines 5 are passed through the outwardly protruding element 8 and then pulled in and attached to the vessel's 1 fixing and securing arrangement (not shown). The vessel 1 will then back away from the offshore structure 2, thereby tightening the towing ropes or lines 5. This will be described as the vessel's 1 towing mode. When the towing ropes or lines 5 have been tightened, the telescopic ladder 3 will be pushed out towards the offshore structure 2. This may be achieved, for example, by the telescopic ladder 3 being connected to an electric, hydraulic or similar arrangement.

In figure 2, moreover, it can be seen that the section 31 of the telescopic ladder 3 is advanced to its foremost position in the vessel's 1 bow, whereupon the section 32 is pushed out towards the landing platform 4 on the offshore structure 2 by means of the electric, hydraulic or similar arrangement. The towing ropes or lines 5, which are passed through the outwardly protruding element 8 in the free end of the telescopic ladder 3 (mounted in the section 32), will support and guide the telescopic ladder 3 during this process, with the result that the outwardly protruding element 8 is brought into contact with the landing platform's 4 opening ("receiving pocket") 7.

When the outwardly protruding element 8 on the section 32 of the telescopic ladder 3 has "landed" in the opening 7 in the landing platform 4, the sections 31, 32 will be held in position relative to each other and the landing platform 4, thereby establishing a secure connection between the vessel 1 and the offshore structure 2. This will occur due to the press force which the insertion and withdrawal arrangement for the telescopic ladder's 3 sections continuous is exerting against the telescopic ladder 3. During this entire process the vessel 1 has been backing away from the offshore structure 2 and will also do this as long as the telescopic ladder 3 is located in the extended and connecting position with the landing platform 4. In figure 3 a link has been established between the vessel 1 and the offshore structure 2, the telescopic ladder 3 being connected to the landing platform's 4 opening 7 via the outwardly protruding element 8. Since the landing platform 4 is located above the telescopic ladder's 3 horizontal "storage position" on the vessel 1, it can be seen from the figure that the telescopic ladder 3 is raised upwards towards the landing platform 4, and that by means of the universal joint the telescopic ladder 3 is not influenced by the vessel's movement in the water.

In figure 4 further details of the landing platform 4 and the framework 9 to which the landing platform 4 is connected are illustrated. The framework 9 is composed of a deck 10 extending round the whole offshore structure 2, which deck 10 is further connected to two "rails" 11 which also extend round the entire circumference of the offshore structure 2. By means of a wheel system 12 the landing platform 4 can be permitted to rotate round the rails 11. Alternatively, the wheel system 12 may also comprise a locking device which can lock the landing platform 4 in a desired and secure position. The landing platform 4 further comprises a superstructure which will protect crew and/or personnel when they are using the system.

The deck 10 will furthermore be arranged adjacent to steps or a lift (not shown). Thus when it is connected to the landing platform 4 via the telescopic ladder 3, the vessel 1 will be able to be headed into wind and weather, since the landing platform 4 will be able to be moved round the entire circumference of the offshore structure

2.

In figure 5 a second embodiment of the present invention is illustrated, where the telescopic ladder 3 is now arranged in the vessel's 1 bow area. In this embodiment the offshore structure 2 also comprises a landing platform 4, but here the landing platform 4 will not be provided rotatably round the circumference of the offshore structure 2. In this case the landing platform 4 will be permanently mounted on the offshore structure 2. In this case the landing platform 4 will be equipped with an opening 7 which can be pivoted around 60 degrees on each side of a starting position, in order thereby to permit the vessel to head into wind and weather. Figure 6 indicates further details of the landing platform 4 according to figure 5, the landing platform 4 now being securely or fixedly connected to the offshore structure 2. The opening 7 is designed as a separate unit and connected to the landing platform 4 in a pivotable manner, thereby enabling the opening 7 to be pivoted to each side of its starting position, as illustrated in the figure. The opening 7 may, for example, be permitted to be pivoted 60 degrees to each side. It is further illustrated that the landing platform 4 in this embodiment comprises two towing ropes or lines 5, where the towing ropes or lines 5 are arranged on each side of the landing platform 4 by means of a winch or gravity-influenced system 9. The winch or gravity-influenced system 9 will be of such a nature that the towing ropes or lines 5 are pulled in and shielded by a tube system when they are not in use.

The landing platform 4 according to the second embodiment may, for example, be retrofitted and connected to already-existing steps or ladders 10 on the offshore structure 2, thereby connecting the landing platform 4 fixedly to the offshore structure 2. The invention has now been explained by means of several non-limiting embodiments. A person skilled in the art will appreciate that it will be possible to carry out a number of variations and modifications of the system for transferring crew and/or personnel between a vessel and an offshore structure or another vessel as described within the scope of the invention, as defined in the attached claims.