EP2944600B1

EP2944600B1 - Crane support and crane for use with the crane support

Info

Publication number: EP2944600B1
Application number: EP14171971.6A
Authority: EP
Inventors: Gerrit Van Wijk; Klaas Jacob Reinigert; Boaz Cochavi
Original assignee: Ardent Maritime Netherlands BV
Current assignee: Ardent Maritime Netherlands BV
Priority date: 2014-05-16
Filing date: 2014-06-11
Publication date: 2017-07-12
Anticipated expiration: 2034-06-11
Also published as: EP2944600A1; CY1119338T1; WO2015174846A1

Description

The invention relates to a crane support and crane for use with the crane support useful in the offshore emergency unloading of container cargo from ships, such a crane is known from document US2051497A1 . The last generations of container vessels have dimensions of about 400 meter in length; have a beam of about 60 meters and a depth of about 30 meters. The height above the waterline is roughly 18+27=45 meters. Apart from the offshore crane vessels, there are at present no existing floating cranes available to unload containers from such a vessel. In addition these offshore crane vessels are either not available or far too expensive and it is doubtful if these cranes can come alongside due to their draft.
Accordingly it is an object of the present invention to propose an improved crane support and crane for offshore emergency unloading of container cargo from ships. In a more general sense it is thus an object of the invention to overcome or reduce at least one of the disadvantages of the prior art. It is also an object of the present invention to provide alternative solutions which are less cumbersome in assembly and operation and which moreover can be made relatively inexpensively. Alternatively it is an object of the invention to at least provide a useful alternative.
To this end the invention provides for a crane support and crane for use with the support as defined in one or more of the appended claims.
The crane support and crane of the invention is designed in such a way that all components of the crane can be lifted on board the stricken vessel with a helicopter and next erected to start discharging the containers.
The crane support and crane of the invention is intended to be used to unload containers from a large c.q. ultra large container vessel, when this vessel has been involved in a collision and subsequent grounding, stranding, explosion and /or fire or is partly submerged. With the assistance of the crane support and crane of the invention discharge of containers is possible onto a barge/supply vessel, which is moored alongside, port as well as starboard side depending on the local conditions. For design conditions a maximum list of 3 degrees and/or a trim of 6 degrees is envisioned.

1. The following minimum design criteria are desireable:
- 1.1. A lifting capacity of 42 tons at a radius of minimum 7.8 to maximum 28.3 meters. The crane is considered a shipboard crane but with an offload of 3 degrees.
- 1.2. Average unloading capacity of 4 containers per hour.
- 1.3. Hook travel preferably at a minimum of 55 meters, to cope with the height of the stowage of containers on deck, and based on a ten containers height on deck.
- 1.4. The machinery to drive the ship's container unloading device preferably is positioned above the containers on a slewing platform or nodal base that is supported by a fixed and stable construction over one bay of containers, and is placed on the main deck. The base frame can be adapted for connection to four or more top corner fittings of adjacent containers, so as to transfer forces caused by wind load and offlead. The distance of the main column or strut to the auxiliary columns or struts can have equal dimensions. It is a preferred option to have the main column designed as an A-frame for more stability, and as forces are reduced the components of main and auxiliary columns can then have the same dimensions.
- 1.5. The various parts of the ship's container unloading device are preferably adapted to be stowed in cargo planes, so as to be airlifted to an airport near the causality site. In this respect the following criteria may also be applicable:
  1. a. Maximum weight: total weight not exceeding 80 tons.
  2. b. A maximum length of 6 meters with a width of 2.44 meters, when parts are stowed on two roller plates.
  3. c. When the height is more than 2.44 meters, the width can be reduced, in correspondence with the fuselage of the cargo plane.
  4. d. At the casualty site all components can be transported to the ship and next airlifted on board the casualty by helicopter so that the ship's container unloading device can be erected. Consequently in view of the weight that a helicopter can transport, the maximum weight of the components should not exceed 3000 kg.
  5. e. Where applicable the individual components can be provided with lifting lugs (D-eyes or an appropriate alternative), so that the components are transported in their preferred positions during erection.
- 1.6. The transfer of the forces emitting from the ship's container unloading device into the ship's deck or upper structure is preferably in compliance within the applicable rules. (Lloyds).
- 1.7. Apart from the required dimensions for transport by plane, for storage purposes, and transport by sea it is also preferred that all parts can be stowed into 40-feet containers.
- 1.8. In the event electric power supply from the ship is not available, a suitable generator set of adequate power can be installed on the contra beam, i.e. beams that rotate with mast and boom. Suggested performance parameters:
  1. a. Voltage 440/660.
  2. b. Frequency 60 Hertz.
  3. c. Emission according Tier 3.
  4. d. Prime mover: 3 phases air-cooled diesel in silent hood.
  5. e. Power: about 35 kW.
- 1.9. From the above requirements it can be concluded, that a minimum construction weight is paramount. The use of high tensile, steel 690 is preferred. In order that the basis of the columns can be welded to ship's construction St 52-3N can be used for those parts.
- 1.10. Temperature range from minus 10 degrees up to plus 50 degrees Celsius.
2. The system also distinguishes the following main construction components:
- 2.1. The foundation or basis comprises of two lattice beams under an angle of 90 degrees with each other. The slewing platform or nodal base is connected to those lattice beams and supported by the main column or strut (the A-frame). The opposite ends of the lattice beams are supported by the two auxiliary columns or struts.
- 2.2. The columns are placed in the appropriate vertical positions. The foundation is placed in a horizontal position on top of the columns. Some minor adjusting devices or tools can be provided in order to fulfil these requirements. Its an option to have the length of the columns adjusted by means of a screw spindle system and a sliding/guide construction, which has XY-hinges. Pre-adjusting during erection is nearly unloaded, while fine adjusting upon erection takes place with only the own weight. Hence a manually operated drive system is possible. Nonetheless an option for a motor drive is kept open.
- 2.3. On the slewing platform, the mast of about 12 meters in length is mounted in vertical position. The top of the mast is kept in position by two shores under an angle, and with a bottom connected to the lattice beams. A hinge construction allows that the mast, with its shores connected, can be erected with the aid an outrigger and an auxiliary tackle.
- 2.4. Hinge points for the 29.4 m boom are positioned at the front of the slewing platform. At the opposite side hinges are situated for the contra beams. On top of the contra beams the following equipment is preferably positioned:
  1. a. hoist and topping winches;
  2. b. hydraulic power packs (2 sets);
  3. c. generator set;
  4. d. operating and control panel; and/or
  5. e. safety system.
- 2.5. With full load the slewing platform with the mast, boom and contra beam have to rotate over an angle of about 250 degrees with a rotation speed of approx.1/2 revolutions per minute. By means of the topping tackle and the topping winch, the boom can be luffed up and down from -3 (minus) to 75 degrees. The net hoisting capacity at the hook preferably is 42 tons from an angle of 15 degrees of the boom to the maximum angle of 75 degrees and with a side and off lead of 3 degrees. The nominal hoisting speed can be a minimum of 10 meters per minute fully loaded.
- 2.6. At the top of the boom preferably a four fall hoisting tackle is situated, in which the spreader frame to discharge containers is suspended by means of four slings. Spreader with the slings are no part of this invention.
- 2.7. The erection of the mast with the two shore,s connected, is performed with an outrigger and an auxiliary tackle. (auxiliary tackle and winch are no part of this specs.) The top of the mast is connected to the fixed stays. The other and is fitted to a 10-fall topping tackle and sheaves mounted into the top shaft of the boom.
- 2.8. In the following description and appended drawings, the main construction of the Ship's Container Unloading Device will be outlined.
- 2.9. Columns are composed of: four columns or struts of which two form an A-frame main column or strut.
  1. (i) a base, which can be adjusted in the vertical position by means of mechanical cylinders, is welded to the Ship's construction at the correct position. This part is preferably of St 52. A bearing construction allows for correction according list and trim of the vessel.
  2. (ii) mid sections; one of about 2.62 meter long, rest of sections about 5.24 meters long (appropriate section length can be varied subject to requirement).
  3. (iii) levelling is done with the cylinders so the lattice beams are in a horizontal position.
  4. (iv) sections can be connected with bolts and nuts and locked with" sheet nuts" or any better solution.
- 2.10. Winches:
  1. a) Hoisting winch:
    - The winch has a nominal hoisting capacity of minimum 11 tons at the outer wire layer and a nominal hoisting speed at this layer of minimal 40 m/min. The wire drums can be provided with "Lebus spirals" and the prime mover can be a hydraulic motor of about 90 kW. Reduction via a planetary gear or a gearbox. A total wire storage capacity of about 300 m of 24 mm diam. in maximum 6 layers. The winch should have the capability of 1,5 times its nominal speed under reduced load conditions.
  2. b) Topping winch:
    - This winch is in essence identical to the hoisting winch except for:
      - A hoisting capacity of nominal 13.5 tons at the third layer and a hoisting speed of approx. 22 m/min. Storage capacity of about 260 m. of 24 mm. diam. wire in max 5 layers, or appropriate alternative. This winch preferably is to have, apart from the standard brake, an additional brake acting on the drum with a holding capacity of one and a halve times the nominal torque.
  3. c) Runner winch:
    - As an option: the crane boom can be extended with a small jib for the installation of a runner of 3 tons. A runner winch can be mounted in the basis of the boom, wire length 100 m and a nominal rope speed of 30 m/min. The steel wire can be of the non-rotating type. The connection points for the jib already can be fitted at the top of the boom. Optionally: above runner system can be made suitable for "man riding".
    - d) All winches to have brake lifting devices, which can be manually operated in case of power failure.
- 2.11. Rigging:
  1. a) Hoisting system:
    - The hoisting system is a 4 fall tackle with a hook travel of min. 53 m, steel wire of 24 mm diameter and a wire length of about 300 m. One end of the wire to have a winch eye and the opposite end a dis-mountable socket, so that this end can pass along the sheave blocks (modified pressed socket or appropriate alternative). The sheaves of the lower block need to have a diam. of about 1 m, in order to avoid twisting of the tackle due to the hoisting height. The ramshornhook is rotating on a roller bearing and all swivel points can be provided with grease nipples as the lower block may be used under water. Provisions can be made that at a later stage so a "power swivel" can be installed. All sheaves rotating on ball/roller bearings and the wire groves can be hardened [300 Br].
  2. b) Topping system:
    - This is a 10 fall tackle with a travel of min. 22 m, steel wire 24 mm diameter. Rope length of minimal 260 m. The wire ends, same end-finish as hoisting wire. The block connection is integrated in the top shaft of the boom, the travelling block is connected to the stays. The running part is leaded along the boom via a lead-sheave to the topping-winch.
  3. c) The stay:
    - Two stay wires have pressed gaff sockets at both ends, a length of about 25 m, and a diameter of 54-56 mm.
  4. d) The shore stays:
    - The wires for the shore stays are connected with the "aft" of the column and are loaded with about 20 tons. Maximum length approximately 33 m. Stacy's can be delivered in sections, so that they can be adapted in length, when containers are stowed in different heights. Turn-buckles can be provided in order to tighten the stays. Minimum of 2 units can be delivered.
- 2.12. Electrical installation:
  1. a) Ship's supply:
    - Ship's supply can be 60 Hertz and 440/660 Volt. The required power can be delivered from the vessels' network or by a generator set of about 35 kW or appropriate alternative. The capacity can be determined when all consumers are clearly defined. Lightning alarm and safety devices, hand tools, communication, and radio control, etc.
  2. b) Subdivision:
    - A switch board can be designed and delivered with the required devices in a watertight box. When in use some covers can be opened for ventilation. Box in free standing mode and with two lifting eyes. Connection of the conductors with plugs/contra plugs and clearly and unchangeable marked.
  3. c) Supply and Consumers:
    - The following connections can be provided:
      - A power connection for either on board supply or for the generator set. Four connections for hand tools via transformer to 230 Volt.
      - Connections for the deck lightning.
      - Connections for the control and safety devices free of distortions (24 Volt DC or appropriate alternative).
      - Connection for the radio distance control (optional).
  4. d) Cables and trays:
    - All cables of the marine type and protected to avoid electromagnetic disturbance, installation should comply with the EMC requirements. Cables can be clearly marked and connected via plugs, so that no mistakes can be made when, cables are connected. The cables leading to the moving parts of the ship's container unloading device can be long enough so that a 270 degree of rotation is allowed as well as the topping. To avoid damage to the cables a flexible cable tray can be installed near the rotating points.
  5. e) Lightning:
    - Deck lightning can be provided in boom, mast and both shore beams in such a way that a good visibility is obtained over the working area [min. 200 Lu x, or appropriate alternative].
  6. f) Safety arrangements:
    - The ship's container unloading device can be provided with load-moment protection by measuring: boom angle, load in hoisting tackle and orientation to avoid touching the shores. Protection against to blocks hoisting and nearly empty wire drums. Safety devices for the diesel engines can include: oil pressure, temperature oil, and cooling water, over speed, and/or hydraulic oil temperature and pressure. A load signal can be integrated in the hydraulic control system, so that in case of an overload or too high temperature, the hoisting speed is automatically reduced. At tactical places emergency stops have can be installed. All this equipment can be of approved types for use in a marine environment.
- 2.13. Hydraulic power packs:
  - To drive the winches and slewing platform, two sets of diesel hydraulic power packs can be delivered and installed on the base beam. Power packs complete with all ancillaries and covered with a noise dampening hood. Noise level 65 Dba at 1 m distance. Emissions to comply with Tier3 and exhausts of all diesel engines provided with spark arrestors. Each diesel-engine drives a variable hydraulic piston pump unit with load sensing of about 100 kW to drive the two winches, the slewing drives and the optional runner winch. A small hydro pump can be installed for operating the brakes. Design hydraulic pressures of maximum 350 bar, peak pressure of 325 bar and a working pressure of maximum 290 bar. A large capacity diesel oil and hydraulic oil tank can be integrated in the base frame. A cooler for the hydraulic system can be of a large capacity so to dissipate the heat from the recovered power during lowering of load under full capacity and in tropical condition. Preferable the system can be of the "open loop" and directly controlled from the deck control stand, mounted on the base beam. The interconnection between the units can be hydraulic hoses with quick connecting self closing valves. All safety and protection devices are part of the delivery.
- 2.14. Ladders and platforms:
  - Ladders, platforms and railings are preferably installed for rigging, maintenance and inspection. These items are also part of the finished device.
- 2.15. The slewing drives:
  - Rotation of the mast with the boom is executed with two hydro controlled slewing drives of about 15 kW with a reduction of approx. 1000, so that rotations speed of approximately 0.3 to 0.5 revs/min. is obtained. The gearwheel is situated on the top of the main A columns. The drives to run synchronously in parallel and both should have a parking brake and adjusted in such a way that overload of the boom, caused by side lead, is avoided. Also the hydraulic brake valves should be so adjusted accordingly.
- 2.16. Control and Operating panel:
  - The ship's container unloading device can be directed and controlled from a control stand, which is mounted on the contra beam. Joysticks for hoisting-lowering, for luffing in- and out, rotation left- and right and also for the optional runner winch. All alarms, indicators, service lamps, load and angle indicators of the overload protection can be installed in this control stand. Control stand can be sea-and watertight, have doors for easy access and lifting eyes. As an option a belly panel with radio frequency distance control can be quoted for.

Further advantageous aspects of the invention will become clear from the appended description and in reference to the accompanying drawings, in which:

Figure 1 is a front elevation of a crane support and crane according to the invention;
Figure 2 is a side elevation of the crane support and crane of Figure 1, with the crane boom slewed through 90 degrees;
Figure 3 is a top plan view of the crane in Figure 2;
Figure 4 is an enlarged detail of an upper end of a main strut from the elevation of Figure 1;
Figure 5 is a side elevation of Figure 4;
Figure 6 is a detail view of the elevation of Figure 2;
Figure 7 is a cross section of an end-to-end connection of strut sections;
Figure 8 is an exterior side elevation of the connection shown in Figure 7;
Figure 9A and 9B are partial elevations of a lower end of a strut;
Figure 10 illustrates a particular situation of use of the crane support and crane of the invention;
Figure 11 shows a detail of a mast bottom of the crane of the invention;
Figure 12 is a top view of the mast bottom detail of Figure 11;
Figure 13 is a plan view of a nodal base for the crane of the invention; and
Figure 14 shows a mast top for the crane of the invention.

A front elevation of a crane support 1 and a crane 3 according to the invention is shown in Figure 1. The crane 3 as illustrated is of a derrick type. The crane support structure 1 as shown in Figure 1 has main strut 5, with splayed individual first and second legs 5A, 5B. The main strut 5 is positioned directly under a mast 7 of the derrick type crane 3. As is conventional with derrick type cranes the mast 7 is supported on a nodal base 9 from which also horizontal sill beams extend in diverging directions. A first sill beam 11 is visible in Figure 1. A near end of the first sill beam 11 is connected to the nodal base 9, and a far end of the first sill beam 11 is supported by a first auxiliary strut 13. The main strut 5, with its first and second legs 5A, 5B, and first auxiliary strut 13 are attached and supported from an upper surface 15 of a ship's structure. This ship's structure can be a weatherdeck of a container vessel that has bays of stacked containers separated by gangways extending transversely of the ship's length. Such a bay of containers is indicated by the reference numeral 17 and the main strut 5 and first auxiliary strut 13 are located in a gangway that separates the bay 17 from a next bay of containers. On modern ships such bays of individual containers 19 can be stowed up to ten containers high on weatherdecks (about 28 m high). With such ever increasing stowage heights on container ship decks it has become common practise to interconnect all containers by twistlocks and to lash te lowermost layers of containers to lashing bridges that are provided on such ships transverse of the ship's length and at intervalls commensurate with a forty foot container length. Such lashing bridges can also be used for lashing the main and auxiliary struts of the crane support structure. The crane 3 of this example is a so-called stiff leg derrick and has a first stiff leg 21 that connects a top of the mast 7 to the far and of the first sill beam 11. Pivotally connected to the nodal base 9 is a boom 23 and a topping or luffing arrangement 25 that extends between a free end of the boom 23 and a top end of the mast 7. The boom 23, as illustrated in Figure 1, is rotated to extend transversely of the ship's longitudinal direction. A load hoisting cable 27 extends along the boom 23 and is schematically illustrated to carry a container 19. Topping of the boom 23 and hoisting of the load are controlled by an arrangement of winches, generally indicated by reference numeral 29. The winch arrangement 29 is mounted on an outrigger structure 31.
The crane support 1 and derrick crane 3 are further illustrated in Figure 2, which is a side elevation parallel to a ship's longitudinal direction. In this view the boom 23 of the derrick crane 3 has been rotated to extend in the longitudinal direction of the ship on which strucural surface 15 it is supported. Visible in the view of Figure 2 are a second sill beam 33 and a second stiff leg 35. A far end of the second sill beam 33 is supported on a second auxiliary strut 37. The first auxiliary strut 13, and the main strut 5 hidden therebehind in Figure 2, are both positioned and attached to the ship structure upper surface 15 along a gangway on one side of the bay 17 of stowed containers 19. The second auxiliary strut 37 is positioned and attached to the ship structure at an opposite side of the container bay 17. The gangways between adjacent container bays, as explained above, are usually provided with lashing bridges and the level of such a lashing bridge is indicated by an interrupted line 39 in Figure 2. The other reference numerals indicated in Figure 2 have already been discussed in reference to Figure 1.
In Figure 3 a schematic partial top plan view of Figure 2 is shown. As will be clear from Figure 3, the second sill beam 33 and the second stiff leg 35, which are now overlapping extend at an angle of 90 degrees with respect to the first sill beam 11 and the first stiff leg 21. The boom 23 which is rotatable with respect to the nodal base 9 by a ring gear 41 can be slewed through an angle extending between a first boundary, indicated by interrupted line 43, and a second boundary, indicated by interrupted line 45. This slewing of the boom 23 is above the highest level of containers 19. Also visible in Figure 3 are the respective positions of the first and second auxiliary struts 13, 37.
In Figure 4 an upper detail of the main strut 5 on an enlarged scale is shown. The first leg 5A of the splayed legs at an upper end is provided with a spherical bearing mount 47 engaged between a pivot bracket 49 that supports the nodal base 9. Figure 5 is a side view of Figure 4 and shows in cross section a spherical bearing 51 positioned in the bearing mount 47 and a pivot pin 53 which extends through both the spherical bearing 51 and the pivot bracket 49. The second leg 5B of the main strut 5 is pivoted to the first leg 5A, as shown in Figure 4, by means of a pivot connection 55.
Figure 6 is a partial side view from an opposite direction to that of Figure 5, and generally corresponds to a partial view of Figure 2. Figure 6 again shows the arrangement of the main strut 5 supporting the nodal base 9 by means of the spherical bearing 51 and pivot pin 53. Further it is seen that the ring gear 41 is associated with a mast base 57 for slewing the boom 23 and mast 7 in respect of the nodal base 9, as will be explained below. The outrigger structure 31 extends from the mast base 57 in a direction opposite to the boom 23. The second sill beam 33 extending from the nodal base 9, as shown in Figure 6, is additionally supported using a top corner fitting 19A of an uppermost container 19 stowed on the vessel to which the crane support 1 and crane 3 are mounted. To this end a transverse beam 59 is mounted across two corner fittings 19A of the container 19 by twistlocks 61 and a height adjustable support 63 between the transverse beam 59 and a lower surface of the second sill beam 33. A rigging cable 65 between the beam 59 and the second sill beam 33 is used to take up side loads acting on the crane support 1. Similar rigging can be applied to the first sill beam 11. As illustrated in Figures 7 and 8 the legs 5A, 5B of the main strut 5, and the first and second auxiliary struts 13, 37 are each made of individual sections having a first section end 67 and an opposite end second section end 69. The individual sections have lengths that are convenient to transport or air lift by helicopter. It is to be understood that only intermediate secion will be provided with both the first and second ends 67, 69. Upper and lower end sections of each main 5 and auxiliary struts 13, 37 will only have one of the first and second ends 67, 69. The first section end 67 is formed with a central bore 71 in opposite walls. The second section end 69 has a nose section 73, which snuggly fits inside of the opposite walls of the first section end 67. The nose section 73 can be welded to the inside of the second section end 69, and also has opposite central bores 75 in its portion that aligns with the central bores 71 of the first section end 67. In the example of Figures 7 and 8 the central bores 75 in the nose section 73 have a smaller diameter than the central bores 71 in the first section end 67. Upon aligning of the bores 71, 75 the section ends are united by a transverse bolt 77. The transverse bolt 77 has an excentric head 77A on one end that fits into the larger bore 71 of the first section end 67 on one side, whereas on an opposite side an excentric sleeve 79 is fitted in the opposite larger bore 71 of the first section end 67. By suitable rotation of the bolt 77 and the excentric sleeve 79 the first and second section ends 67, 69 can be firmly engaged with one another, by taking up any play. Thereafter the connection can be immobilised by firmly fastening a nut 81 on the bolt 77. Alternative to this particular example the skilled person will be aware of many other arrangements that will substantially accomplish the same function with similar means. Apart from allowing the sections to be easily transported to a site of emergency, an appropriate selection of varying lengths will also enable the crane support 1 to be adapted to different heights of stacked containers, or to achieve the best possible vertical position for the struts to compensate for list and trim of the ship.
As shown in Figures 9A and 9B a lower end of the struts 5A, 5B, 13, 37, which will be attached by wielding or the like to a ship's structural upper surface 15, are provided with an adjusting arrangement to cope with differences smaller than a smallest strut section. Shown in Figure 9B a bottom end of a lower section of a main strut leg 5A, 5B or one of the first and second auxiliary struts 13, 37 is engaged with a bottom section 83 to telescope therein. Inside the bottom section 83 is a rotatable threaded sleeve 85, which engages a threaded screw spindle 87 that is connected at 89 to the lower section of the strut 5A, 5B, 13, 37. An external drive arranged on the bottom seciton 83 can rotate the threaded sleeve 85 for adjusting the length of the screw spindle 87 that extends beyond the threaded sleeve 85. Such an external drive is not shown, but conventional and well known to a skilled person. Figure 9A shows a partial elevation of the bottom section 83 perpendicular to the view of Figure 9B. Thereby Figure 9A shows that a pedestal 91 for attachment to a ship's structure, such as surface 15, is connected to the bottom section 83 by a spherical bearing arrangement 93 that is very similar to the spherical bearing connection explained in reference to Figures 4 and 5.
Figure 10 shows an extreme situation of use of the crane support 1 and crane 3 of the invention. As shown in Figure 10 the ship structure's upper surface 15 has a list of 30 degrees, and full use is made of the capability of varying the individual lengths of each of the first and second legs 5A, 5B of the main strut 5, as well as of the first auxiliary strut 13, and the second auxiliary strut 37 (the latter only indicated as a dotted line). These individual lengths are obtained by combining appropriate lengths of strut sections and by using the length adjustment described in reference to Figures 9A and 9B. Appropriate section lengths can be 2.6 and 5.2 meters, in combination with bottom sections that offer 0.8 meters of adjustment. This is clearly not a limiting exampole and other and more section lengths or adjustment ranges can be employed.
Figure 11 shows the mast base 57 and the nodal base 9 in somewhat more detail. As indicated in Figure 11 the ring gear 41 is driven by an electric or hydraulic motor 95 through a pinion 97 for slewing the boom 23. The boom 23 (deleted in Figure 11) is pivotally connected to pivot bearing 99. Figure 12 shows a top view of the mast base 57 and reveals a stub shaft 101 that extends all the way through the mast base 57 and the nodal base 9 to pivotally journal the mast base 57 with respect to the nodal base 9 for slewing the boom 23 between the boundaries 43, 45 indicated in Figure 3.
Figure 13 shows a top view of the nodal base 9, which has a bore 103 for receiving the stub shaft 101 of the mast base 57. It is further clear from Figure 13 that the nodal base 9 is substantially in the form of a "T", with a first branch 9A, and opposite second and third branches 9B, 9C. The first branch 9A forms a connection for the second sill beam 33. The second and third branches 9B, 9C form optional connections for the first sill beam 11, which thereby can optionally extend in one of the two opposite directions. This option is convenient and offers versability in that it offers freedom to have the mast 7 of the crane 3 selectively in front of, or behind a bay of containers 17
While the stiff leg derrick crane 3 used in the present invention is generally similar to the stiff leg derrick type crane described in patent publication US 3148778 the mast top connection has been further improved as shown in Figure 14. As shown in Figure 14, the top of the mast 7 has a writst pin 105 about which a collar 107 is journalled. The collar 107 has a lug 109, which is pivotally mounted by a transverse pin 111 to the second shift leg 35, as well as by a further lug (not visible, but perpendicular to the lug 109) to the first stiff leg 21 (also not visible in Figure 14, but analogue to the connection of the second stiff leg). The collar 107 allows the mast 7, together with the boom 23 at its lower end to rotate or slew about the wrist pin 105. The improvement is that the forces introduced into the collor 107 by the luffing arrangement 25 are equally distributed over top and bottom cable socket connections 113, 115. Each of the top and bottom cable socket connectors 113, 115 is equally spaced at a distance 117 from a center of the wrist pin 105 and collar 107. This arrangement prevents the introduction-of-skewing forces in the mast top bearing and thereby allows to reduce weight in the construction.
Accordingly there is disclosed a ship's container unloading device that comprises a crane support 1 for supporting from a ship structure a derrick type crane 3 for offshore emergency unloading of container cargo, and the derrick type crane 3 for use with the support 1. The derrick type crane 3 has a nodal base 9 supporting a substantially vertical mast 7, and first and second sill beams 11, 33 extending horizontally from the nodal base 9 in substantially perpendicular directions. The crane support 1 includes a main strut 5 with downwardly diverging first and second legs 5A, 5B, each leg having upper and lower ends and arranged for supporting the nodal base 9 of the derrick type crane 3 from the upper ends, a first auxiliary strut 13 with upper and lower ends being adapted to support from its upper end the first sill beam 11 at a location remote from the nodal base 9, and a second auxiliary strut 37 having upper and lower ends and being adapted to support from its upper end the second sill beam 33 at a location remote from the nodal base 9. The lower ends of the main, first auxiliary, and second auxiliary struts 5, 13, 37 are adapted to be attached to a ship structure, and an upper end of at least one of the main, first auxiliary, and second auxiliary struts 5, 13, 37 is adapted to be rigged to at least one of a ship structure, and a container cargo attached to the ship structure.
It is thus believed that the operation and construction of the present invention will be apparent from the foregoing description and drawings appended thereto. For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described. It will be clear to the skilled person that the invention is not limited to any embodiment herein described and that modifications are possible which may be considered within the scope of the appended claims. Also kinematic inversions are considered inherently disclosed and can be within the scope of the invention. In the claims, any reference signs shall not be construed as limiting the claim. The term 'comprising' and 'including' when used in this description or the appended claims should not be construed in an exclusive or exhaustive sense but rather in an inclusive sense. Thus the expression 'comprising' as used herein does not exclude the presence of other elements or steps in addition to those listed in any claim. Furthermore, the words 'a' and 'an' shall not be construed as limited to 'only one', but instead are used to mean 'at least one', and do not exclude a plurality. Features that are not specifically or explicitly described or claimed may be additionally included in the structure of the invention without departing from its scope. Expressions such as: "means for .." should be read as: "component configured for .." or "member constructed to .." and should be construed to include equivalents for the structures disclosed. The use of expressions like: "critical", "preferred", "especially preferred" etc. is not intended to limit the invention. Additions, deletions, and modifications within the purview of the skilled person may generally be made without departing from the scope of the invention, as determined by the claims.

Claims

Crane support for supporting from a ship structure a derrick type crane (3) for offshore emergency unloading of container cargo, the derrick type crane having a nodal base (9) supporting a vertical mast (7) and first and second sill beams extending horizontally from the nodal base in substantially perpendicular directions, characterised in that the crane support includes:
a main strut (5) having downwardly diverging first and second legs, (5a, 5b) each leg having upper and lower ends and being arranged for supporting a nodal base of a derrick type crane from the upper ends;

a first auxiliary strut (13) having upper and lower ends adapted to support from its upper end a first sill (11) beam of a derrick type crane at a location of the first sill beam remote from the nodal base; and

a second auxiliary strut (37) having upper and lower ends and adapted to support from its upper end a second sill beam (33) of a derrick type crane at a location of the second sill beam remote from the nodal base,

wherein the lower ends of the main, first auxiliary, and second auxiliary struts are adapted to be attached to a ship structure, and

wherein an upper end of at least one of the main, first auxiliary, and second auxiliary struts is adapted to be rigged to at least one of a ship structure, and a container cargo attached to the ship structure.
Crane support according to claim 1, wherein spherical bearings (47) are provided between the upper ends of the struts and the relevant nodal base or sill beams supported thereon, and between the lower ends of the struts and the ship structure.
Crane support according to claim 1 or 2, wherein at least one of the first and second legs of the main strut and the first and second auxiliary struts is formed from a plurality of disconnectable individual sections of a given predefined length.
Crane support according to claim 3, wherein the plurality of individual sections of a given predefined length comprises individual sections of different predefined lengths.
Crane support according to one of claims 1 to 4, wherein the upper end of the at least one of the main, first auxiliary, and second auxiliary struts is adapted to be rigged to at least three corner fittings of uppermost containers forming the container cargo attached to the ship structure.
Crane support according to claim 5, wherein a transverse beam is mounted across two corner fittings by twistlocks.
Crane support according to claim 6, wherein a height adjustable support is interposed between the transverse beam and a lower surface of one of the first and second sill beams.
Crane support according to claim 5, 6 or 7, wherein a rigging cable extends between the transverse beam and one of the first and second sill beams to take up side loads acting on the crane support.
Crane support according to one of claims 1 to 8, wherein the lower ends of the main, first auxiliary, and second auxiliary struts are adapted to be attached to a ship structure by welding.
Crane for use with the crane support of any of the preceding claims, comprising a nodal base supporting a substantially vertical mast and first and second sill beams extending horizontally from the nodal base in substantially perpendicular directions, a first stiff leg extending between a top of the mast and a far end of the first sill beam, and a second stiff leg extending between the top of the mast and a far end of the second sill beam, and a boom pivotally associated with a bottom of the mast and having a free end suspended from the top of the mast by a luffing arrangement, wherein the mast top has a wrist pin with which it is journalled in a collar attached to each of the first and second stiff legs, and wherein the luffing arrangement is anchored to the top of the mast at equal distances above and below a center of the wrist pin.
Crane according to claim 10, wherein the nodal base has a T-shape with one of the first and second sill beams attached to a stem of the T-shaped nodal base, and allowing selective attachment of the other of the first and second sill beams to one of the laterally extending bars of the T-shaped nodal base.