NL2018375B1

NL2018375B1 - Marine jack-up type crane vessel and methods of operation

Info

Publication number: NL2018375B1
Application number: NL2018375A
Authority: NL
Inventors: Roodenburg Joop
Original assignee: Itrec Bv
Priority date: 2017-02-14
Filing date: 2017-02-14
Publication date: 2018-09-06

Abstract

The present invention relates to a marine jack-up type crane vessel and a method of operation thereof. Aa hoisting crane is mounted to the hull, comprising a substantially hollow vertical column around which a slew bearing extends, guiding and carrying a boom connection member to which a boom is mounted. A topping winch is provided and an associated topping cable for pivoting the boom up and down. A hoisting winch and an associated hoisting cable are provided for hoisting a load. A revolving cable guide is arranged at a top of the column via an associated bearing structure. The topping winch is disposed such that the topping cable extends from the topping winch upward through the column to the revolving cable guide. The horizontal boom pivot axis is at a height with respect to the cargo deck exceeding 35 meters, and the revolving cable guide is at a height with respect the cargo deck exceeding 60 meters.

Description

Octrooicentrum

Θ 2018375

(21) Aanvraagnummer: 2018375 (22) Aanvraag ingediend: 14 februari 2017 (51) Int. CL:

B66C 23/52 (2017.01) B66C 23/78 (2017.01) E02B

17/02 (2017.01)

(4^ Aanvraag ingeschreven:	(73) Octrooihouder(s):
6 september 2018	Itrec B.V. te SCHIEDAM.
(43) Aanvraag gepubliceerd:
-	(72) Uitvinder(s):
	Joop Roodenburg te SCHIEDAM.
Octrooi verleend:
6 september 2018
	(74) Gemachtigde:
(45) Octrooischrift uitgegeven:	ir. H.V. Mertens c.s. te Rijswijk.
7 november 2018

Marine jack-up type crane vessel and methods of operation © The present invention relates to a marine jack-up type crane vessel and a method of operation thereof. Aa hoisting crane is mounted to the hull, comprising a substantially hollow vertical column around which a slew bearing extends, guiding and carrying a boom connection member to which a boom is mounted. A topping winch is provided and an associated topping cable for pivoting the boom up and down. A hoisting winch and an associated hoisting cable are provided for hoisting a load. A revolving cable guide is arranged at a top of the column via an associated bearing structure. The topping winch is disposed such that the topping cable extends from the topping winch upward through the column to the revolving cable guide. The horizontal boom pivot axis is at a height with respect to the cargo deck exceeding 35 meters, and the revolving cable guide is at a height with respect the cargo deck exceeding 60 meters.

NL Bl 2018375

Dit octrooi is verleend ongeacht het bijgevoegde resultaat van het onderzoek naar de stand van de techniek en schriftelijke opinie. Het octrooischrift komt overeen met de oorspronkelijk ingediende stukken.

P33036NL00/IWO

Marine jack-up type crane vessel and methods of operation

The present invention relates to a marine jack-up type crane vessel and a method of operation of such a marine vessel.

It is commonly known to use marine jack-up type crane vessels for offshore purposes, such as drilling of offshore wells for oil and gas and for the installation of offshore windmills. The term “jack-up type” refers to the use of a jacking system usually involving a rack and pinion mechanism to elevate a hull with respect to the legs.

Such a marine jack-up type crane vessel comprises:

a hull with a cargo deck, a plurality of jack-up legs, each of which legs is movable in a vertical direction with respect to the hull, wherein the length of a leg exceeds 50 meters, and a plurality of elevating units for moving the legs relative to the hull, and for bringing the vessel in an operational position wherein the legs engage the seabed and the hull is essentially above water level, and part of the jack-up legs project above the cargo deck.

Because of the high loads being transferred from the hull to the legs, the marine jack-up type crane vessel is structurally quite strong and suitable to support a crane.

In a so-called “around-the-leg-crane”, the jack-up type marine vessel comprises a plurality of generally vertical leg openings extending through the hull, and the jack-up legs extend through the hull via one of said vertical leg openings. A ring bearing is mounted on the hull about one of the vertical leg openings, said ring bearing being structurally anchored to the hull, independently of the leg. The crane comprises a revolving superstructure mounted upon said ring bearing around the leg, and a lattice boom pivotally mounted to the revolving superstructure.

Alternatively, a deck-mounted rope luffing crane is provided, e.g. wherein rope luffing is effected in a so-called A-frame design to provide optimal stability and reliability. Such a deck-mounted rope luffing crane comprises a deck-mounted crane foot, provided with a slew bearing at the top end thereof. A boom is mounted to a boom connection member carried by

-2the slew bearing. The boom is pivotal up and down by a luffing cable, extending from an Aframe mounted to the slew bearing to the boom.

Alternatively, a so-called mastcrane can be provided an a marine jack-up type crane vessel, commercially available from the applicant. One of the known advantages of a mastcrane is that the footprint of the crane is relatively small. A mastcrane is a hoisting crane mounted to the hull, comprising:

o a substantially hollow vertical column with a foot which is fixed to the hull, and with a top, o a slew bearing, which extends around the vertical column and guides and carries a boom connection member, so that the boom connection member is revolvable around the column, o a boom pivotally mounted to the boom connection member about a substantially horizontal boom pivot axis so that the boom is pivotal up and down, o a topping winch and an associated topping cable for pivoting the boom up and down, o a hoisting winch and an associated hoisting cable for hoisting a load;

o a revolving cable guide arranged at the top of the column and having a top pulley for at least the topping cable, wherein the revolving cable guide is mounted via an associated bearing structure, such that said revolving cable guide follows slew motions of the boom about the vertical column and adopts substantially the same angular position as the boom, wherein the topping winch is disposed such that the topping cable extends from the associated topping winch upward through the column to the revolving cable guide and from said revolving cable guide to the boom.

The aim of the present invention is to provide a more versatile marine jack-up type crane vessel.

This aim is arrived in that a marine jack-up type crane vessel is provided with a hoisting crane comprising a substantially hollow vertical column according to the preamble of claim 1, wherein the horizontal boom pivot axis is at a height with respect to the cargo deck exceeding 35 meters, and wherein the revolving cable guide is at a height with respect the cargo deck exceeding 60 meters.

The advantage of this elevated boom pivot axis is that the crane is more versatile, as it is operable in multiple operational positions with part of the jack-up legs projecting less or more above the cargo deck, the crane operations not being limited by these projecting parts of the

-3jack-up legs. In particular, the configuration allows the overboarding of an object by slewing the boom of the crane over one of the jack-up legs, and the engaged object around said jack-up leg.

The hoisting crane of the invention is mounted to the hull. In particular, the foot of the vertical column is fixed to the hull. It is conceivable that the foot is mounted to the cargo deck of the vessel. Alternatively, it is also conceivable that the foot is integrated with the hull of the vessel.

The hoisting crane comprises a slew bearing extending around the vertical column. The slew bearing guides and carries a boom connection member, so that the boom connection member is revolvable around the column. A boom is pivotally mounted to the boom connection member about a substantially horizontal boom pivot axis, so that the boom is pivotal up and down. This boom pivot axis is provided at least 35 meters above deck, preferably 50 meters above deck. By pivoting the boom downwards, the tip of the boom can be lowered to the cargo deck. By pivoting the boom upwards, the boom can be positioned in an upward direction.

In embodiments, the boom pivot axis essentially falls within the footprint of the column. In particular, the boom pivot axis is close to the central axis of the column. It is conceivable that the entire pivot axis is within the footprint. However, it is also conceivable that although the pivot axis is close to the central axis of the column, the outer ends of the pivot axis extend beyond the footprint. The boom pivot axis essentially falling within the footprint is advantageous as it allows the crane to relatively heave hoist loads close to the column. For example, loads having a weight of at least 1500 mt as close as 10 meters from a central axis of the column. This is highly advantageous in use on a jack-up vessel, transporting heavy and large loads to be installed overboard, to be handled by the crane. Accordingly, such advantageous crane design even further enlarges the versatility of the crane vessel.

In embodiments, the marine jack-up type crane vessel is configured to transport one or more monopiles and other equipment for offshore wind energy, such as turbines, nacelles, transformers, transmission infrastructural components, etc etc. for wind-energy purposes, and the crane is configured to handle such monopiles and equipment. Advantageously, the vessel and crane are configured to transport and handle a power transformer, having a weight between 1000-3000 mt and dimensions exceeding 15x15 meters (19x23meters).

-4With the boom pivot axis falling within the footprint of the column, it is possible to bring the boom in an upward raised position, wherein the boom, or part of the boom, is also essentially within the footprint of the column. This is in particular advantageous during transit, as this allows transport without an elevated boomrest.

The footprint of the column is defined as the shape and size occupied by the column, seen in a vertical direction and projected on a horizontal area. Hence, for a fully cylindrical column, the footprint corresponds to a cross-sectional area. For tapered cylindrical columns, the footprint corresponds to the largest cross-sectional area of the column. An advantageous crane design wherein the boom pivot axis falls within the footprint of the column comprises a tapered column.

In the present invention, advantageously the column is tapered towards the top. For example, the column is tapered between a cross-sectional diameter exceeding 10 meters and a cross section of less than 5 meters at the top. The column preferably has a circular cross-section, over the entire length or over part of the length of the column. In such an embodiment, the slew bearing e.g. extends around a part the column having a crosssectional diameter of between 6 and 7,5 meters. It is conceivable that the tapered column comprises a foot which is not tapered. In particular, embodiments of the column are envisaged having a square foot and a truncated cone on top thereof. It is also conceivable that the foot of the column is smaller than the footprint area of the column. This is in particular advantageous in embodiments wherein the foot of the column is mounted to the hull, e.g. on the cargo deck of the vessel, adjacent a board of the vessel, and thus the foot of the column matches the frame and frame spacings of a vessel. The larger column diameter and hence larger footprint area of the column, extending beyond the cargo deck of the vessel, is advantageous to provide the topping and/ or hoisting winch on a rotating winch platform.

In embodiments, the centre of gravity of the crane including the boom is at a level below a horizontal plane extending through the boom pivot axis. Such a low centre of gravity is highly advantageous for the versatility of the crane, and is in particular achieved with the particular crane design.

In embodiments, the boom has a length exceeding 40 meters. Preferably, the length of the boom exceeds 55 meters. Such a boom length results in a maximum lifting height of the crane of over 100 meters above the cargo deck, further attributing to the versatility of the crane. Advantageously, the hoisting cable extends to an outer end of the boom.

-5Advantageously, the hoisting crane further comprising a flyjib, mounted to an outer end of the boom about a flyjib pivot axis which is parallel to the boom pivot axis.. A flyjib also attributes to the versatility of the crane. Preferably, the flyjib has a length of 20-30 meter, resulting in a maximum lifting height of the crane of over 125 meters above the cargo deck.

The provision of a flyjib enables the presence of an auxiliary hoist, having an auxiliary hoist cable extending to an outer end of the flyjib. Such an auxiliary hoist is e.g. adapted to handle a nacelle of a windmill. Furthermore, the provision of a flyjib enables the presence of a whip hoist, having a whip hoist cable extending to the outermost end of the flyjib. Such additional hoist cables enlarges the capacity of the crane in terms of reach and/ or load, and hence the versatility.

The flyjib is pivotal up and down relative to the boom preferably by operating a flyjib winch and associated flyjib cable. In embodiments, the flyjib winch is mounted to the slew bearing. Possibly, a strut is provided, extending perpendicular to the flyjib pivot axis, to guide the flyjib cable.

The hoisting crane comprises a so-called topping winch and an associated topping cable for pivoting the boom up and down. For hoisting a load, a hoisting winch and an associated hoisting cable are provided.

At least the topping winch is disposed such that the topping cable extends from the associated topping winch upward through the column to the cable guide and from said cable guide to the boom.

In embodiments, both the topping winch and the hoisting winch are disposed such that both the topping cable and the hoisting cable extend from the associated winch upward through the column to the cable guide and from said cable guide to the boom.

The hoisting crane comprises a hollow column with a top. A revolving cable guide is arranged at the top of the column, having a top pulley for at least the topping cable. The cable guide is mounted via an associated bearing structure, such that said cable guide follows slew motions of the boom about the vertical column and adopts substantially the same angular position as the boom. This cable guide is a height with respect the deck exceeding 60 meters, preferably exceeding 85 meters. Possibly, the top pulley is also adapted to guide the hoist cable.

-6Possibly the topping winch and/ or the hoisting winch is provided within the column, or below the column. It is possible that the topping winch and/ or the hoisting winch is provided on the cargo deck, but the topping winch and/ or the hoisting winch could also be provided in the hull of the vessel.

In embodiments, the topping winch, and possibly also the hoisting winch, are arranged on a rotatable winch support, which is rotatable about a rotation axis substantially parallel with the vertical column, such that the winch support is mounted movable with respect to the vertical column. Such a rotatable winch support is further described in WO 2009/048316 of the same applicant. Preferably, the winch support has an associated drive motor assembly for moving the winch support in such a manner that the winch support maintains a substantially constant orientation with respect to the boom in the event of slew motions of the boom about the vertical column.

The marine jack-up type crane vessel comprises a hull with a cargo deck. Conceivable hull dimensions are 100-140 meters in length, and 30-50 meters in width. Preferably, the hull is a self-propelled vessel, with crew accommodation, and possibly a helicopter platform, at the bow area of the deck.

The marine jack-up type crane vessel comprises a plurality of jack-up legs, generally 4 or 6 legs, each of which legs is movable in a vertical direction with respect to the hull. The length of a leg exceeds 50 meters, preferably 65 meters.

It is conceivable that a plurality of generally vertical leg openings extend through the hull, and that at least some, preferably all of the jack-up legs extend through the hull via one of said vertical leg openings. Alternatively, the jack-up legs are provided adjacent the hull.

A plurality of elevating units is provided adjacent the legs, preferably on deck, for moving the legs relative to the hull, and for bringing the vessel in an operational position wherein the legs engage the seabed and the hull is essentially above water level. In the operational position, part of the jack-up legs project above the cargo deck. The deeper the bottom of the water, the larger the part of the legs extending under water, and hence the less part of the legs extends above deck. Accordingly, in shallow water, a larger part of the jack-up legs will extend above deck. In the prior art, this larger part hindered the use of the crane. In deeper water, the jack-up vessels having relatively short legs will not be able to operate.

-7The present invention also relates to a method of operation of a marine jack-up type crane vessel at a variety of water depths with associated operational positions of the vessel, wherein the marine jack-up type crane vessel transports a large object at the cargo deck, and wherein the crane is configured to handle such a large object, the method comprising the steps of:

engaging the large object by the hoist cable;

picking up the large object from the cargo deck, generally by actuating the hoisting winch and/or by pivoting the boom;

overboarding the large object by slewing the boom of the crane over one of the jackup legs, and the engaged large object around said jack-up leg.

In embodiments, the large object is a power transformer or monopile for wind-energy purposes. Such a power transformer e.g. has a weight around 2500 mt, and dimensions of 20x25 meters, e.g. 19x23 meters.

The invention will be further elucidated in relation to the drawings, in which:

Fig. 1 represents a top view of a possible embodiment of a marine jack-up type crane vessel of the invention;

Fig. 2a represents a cross-sectional side view of the marine jack-up type crane vessel of fig. 1;

Fig. 2b represents the cross-sectional side view of fig. 2a in a distinct operational configuration;

Fig. 3 represents a cross-sectional side view, perpendicular to the cross-section of figs. 2a and 2b, of the hoisting crane part of the marine jack-up type crane vessel of figs. 1 and 2a and 2b;

Fig. 4 shows the hoisting crane of figs. 1 and 2a and 2b in cross-section in further detail;

Fig. 5 shows distinct orientations of boom and flyjib of the hoisting crane of figs. 1 and 2a and 2b;

Fig. 6 shows a detailed view of the flyjib of the hoisting crane of figs. 1 and 2a and 2b.

In figs. 1 and 2a and 2b, a marine jack-up type crane vessel 1 according to the present invention is shown in top view and cross-sectional side view, respectively.

The marine jack-up type crane vessel 1 comprises a hull 2 with a cargo deck 3. The hull has a bow side 2a and a stern side 2b, wherein crew accommodation 4a and a helicopter platform 4b are provided at the bow side 2a.

-8A plurality of jack-up legs 5a-5f, here 6 legs, is provided, wherein each of the legs is movable in a vertical direction with respect to the hull 2. In the shown embodiment, a plurality of generally vertical leg openings 6a-6f extend through the hull, and the jack-up legs extend through the hull via an accompanying one of said vertical leg openings 6a-6f. A plurality of elevating units 7a-7e is provided, one for each leg, which are schematically shown in fig. 1. The elevating units 7a-7e are provided for moving the legs 5a-5f relative to the hull 2, and for bringing the vessel in an operational position wherein the legs engage the seabed S and the hull is essentially above water level W, and part of the jack-up legs project above the cargo deck 3.

The length of the exemplary vessel shown in figs. 1 and 2 is 120 meters, and the length of the shown legs is about 65 meters. In the operational position shown in fig. 2a, about 20 meters of the jack-up legs project above the cargo deck 3. In fig. 2a, the fully retracted position of jack-up leg 5d is indicated in dashed lines, with the top end of the jack-up leg 5d’ at an elevated position. With the jack-up legs in the fully retracted position, the vessel is able to sail around.

The marine jack-up type crane vessel 1 is configured to transport one or more monopiles. Here, three monopiles 8a, 8b, 8c are visible on the cargo deck 3, each having a length of 80 meters. The vessel further transports a power transformer 9 for wind-energy purposes. The shown power transformer has a weight between 1000-3000 mt, in particular 2500 mt, and dimensions exceeding 15x15 meter, in particular 9x23meters. In fig. 1, the power transformer 9 is shown in three different positions, during overboarding of the power transformer 9.

On the cargo deck 3, an auxiliary crane 10 is provided and a hoisting crane 20 according to the present invention. Auxiliary crane 10 is not shown in figs. 2a and 2b. The auxiliary crane 10 is provided at the starboard side of the vessel, close to the jack-up leg 5b, between legs 5a and 5b. The hoisting crane 20 is provided at the port side of the vessel, between jack-up legs 5e and 5d.

Hoisting crane 20 is mounted to the hull 2. It comprises a substantially hollow vertical column 21 with a foot 22 which is fixed to the hull, and with a top 23.

The foot 22 has an essentially rectangular cross section, and is here mounted at the port side 2c of the hull, integral with part of the hull 2. In particular in the side views of fig. 3 and fig. 5, it is visible that the foot 22 has a dimension which is smaller than that of the vertical

-9column 21. Here it is visible that the foot 22 is mounted at the port side 2c of the hull, while part of the vertical column 21 protrudes beyond the hull of the vessel.

In the shown embodiment, the vertical column 21 has a circular cross section, starting with a cylindrical portion 21c on top of the foot. The diameter of this cylindrical portion 21c corresponds to two of the side lengths of the rectangular foot 22, as visible in the side views in figs. 2a and 2b and fig. 4. The other sides of the rectangular foot 22 of the shown embodiment are slightly smaller than the diameter of the cylindrical portion 21c of the column, which is visible in the side views of figs. 3 and 5.

On top of the cylindrical portion 21c, the vertical column 21 comprises a truncated conical portion 21b, and on top thereof a distinct truncated conical portion 21a, being tapered in a less steep degree. It is noticed that the cylindrical cross-section and overall tapered shape of the vertical column is highly advantageous, but other configurations are also possible, such as tower having a rectangular or square cross-section, and towers being tapered in a stepwise manner between cylindrical portions of decreasing diameter.

A slew bearing 25 extends around the vertical column 21, here between truncated conical portion 21b and truncated conical portion 21a. The slew bearing guides and carries a boom connection member 26, so that the boom connection member is revolvable around the column 21.

A boom 24 is pivotally mounted to the boom connection member 26, about a substantially horizontal boom pivot axis 24P so that the boom 24 is pivotal up and down. According to the present invention, the horizontal boom pivot axis is at a height with respect to the deck exceeding 35 meters. Here, the boom pivot axis 24 P is at a height of 50 meters above deck. In fig. 2a it is visible that his elevated boom pivot axis 24 P does not allow crane operations in the fully retracted position of jack-up leg 5d, indicated with reference numeral 5d’. However, it will be understood that in shallow water depths with jack-up legs extending a large extent above deck, up to 40-50 meters, the boom 24 of the hoisting crane 20 will be able to slew over the jack-up legs.

In the shown embodiment, as is advantageous, the boom pivot axis 24P falls within the footprint of the column 21, wherein the footprint is defined as the shadow of the column on a horizontal surface, i.e. the area occupied by the column when seen in vertical direction. The advantage of this position of the boom pivot axis close to the column is that it allows the

- 10crane to hoist loads having a weight of at least 1500 mt as close as 10 meters from a central axis C of the column.

In the top view of fig. 1, it is visible that the power transformer 9 is a large object, positioned close to the crane. To be able to handle such a large object, the crane and the object are advantageously positioned close to one another as the largest hoist capacity of a crane is at the smallest radius. For example, up to 25 meters from the central axis C of the column, a hoist capacity of up to 2500mt is conceivable, which drops to a capacity of 1800 mt at 30 meters, and a capacity of 1000 mt at 40 meters. For this reason, it is advantageous to position the hoisting crane at a central area on the cargo deck of the vessel, close to objects to be handled, and not at the stern of the vessel. The crane of the present invention is advantageously configured to handle such monopiles and a power transformer.

The hoisting crane 20 comprises a topping winch 30 and an associated topping cable 31 for pivoting the boom 24 up and down. In fig. 5, an erected position of the boom 24’ is shown, and a more lowered position of the boom 24.

Furthermore, a hoisting winch 35 and an associated hoisting cable 36 are provided for hoisting a load. Hoisting cable 36 extends to an object suspension device 37, here comprising a hook 38, adapted to connect to a load such as transformer 9.

In the shown embodiment, as shown in further detail in fig. 2b, actually a combination of three hoisting winches 35a, 35b and 35c is provided, with associated hoisting cables 36a, 36b, 36c, to obtain an enlarged hoist capacity, e.g. exceeding 2500 mt. In the side view of fig. 2b, the hoisting cables 36a, 36b, 36c overlap, which is indicated in general with reference numeral 36.

Furthermore, it is visible in the detailed view of fig. 2b, that at the top end of the boom 24, the three hoisting cables 36a-c are guided by 3 pulleys 39a-c. The three hoisting cables 36a-c all extend to the object suspension device 37, which here comprises a configuration of pulleys and yokes to be able to provide a versatile system, suitable to hoist heavy loads such as the transformer 9, and to upend monopiles such as visible in fig. 3.

The hoisting crane 20 is provided with a revolving cable guide 40 arranged at the top 23 of the column 21, which is mounted via an associated bearing structure, such that said cable guide follows slew motions of the boom 24 about the vertical column and adopts substantially the same angular position as the boom.

- 11 In the shown embodiment, both the topping winch 30 and the hoisting winches 35a-c are disposed in the cylindrical portion 21c of the column 21, such that both the topping cable 31 and the hoisting cables 36a-c extend from the associated topping winch 30 and hoisting winches 35a-c upward through the column 21 to the cable guide 40 and from said cable guide to the boom 24.

In the shown embodiment, the topping winch 30 and the hoisting winches 35a-c are arranged on a rotatable winch support 34, which is rotatable about a rotation axis substantially parallel with the vertical column, such that the winch support is mounted movable with respect to the vertical column.

The revolving cable guide 40 comprises a top pulley 41 for at least the topping cable 31, and here also for the hoist cables 36a-c. The revolving cable guide 40 is at a height with respect the cargo deck exceeding 60 meters, here over 80 meters.

Despite this lengthy construction, the design of the hoisting crane 20 is advantageously such that the center of gravity G of the crane, including the boom 24, is at a level below a horizontal plane extending through the boom pivot axis 24P. This centre of gravity G is indicated in fig. 4, with the boom including an angle of 86° with the horizontal. In fig. 2a, the centre of gravity G is also shown, for the configuration with the boom extending horizontally. It is noticed that in fig. 2a, two positions of the boom 24 are indicated, for illustrative purposes.

The hoisting crane 20 has a boom 24, here having a length exceeding 40 meters, in particular exceeding 50 meters. The hoisting cables 36a-c extend to a top end of the boom 24, via a pulley to an object suspension device 37, here comprising a hook 38, adapted to connect to a load such as transformer 9 as visible in fig. 2b, or to a monopile 8a as shown in fig. 6.

In the configuration of fig. 3, it is visible that the object suspension device 37 is dispensed with, and that hoisting cables 36a, 36b engage opposite sides of a monopile 8a. Advantageously, the lines 36a, 36b can individually be activated via winches 35a, 35b, to upend the monopile.

The hoisting crane 20 as shown is further provided with a flyjib 50, mounted to an outer end of the boom about a flyjib pivot axis 50P which is parallel to the boom pivot axis 24P so that

- 12 the flyjib is pivotal up and down. A flyjib winch 52 is provided, and associated flyjib cable 51, to pivot the flyjib up and down. In the shown embodiment, as is preferred, the flyjib winch 52 is mounted to the boom connection member 26. It is also conceivable that the flyjib winch is mounted to the boom, or that it is also provided inside the column together with the other winches. Furthermore, a strut 53 is provided to guide the flyjib cable 51.

In fig. 5, distinct positions of the flyjib 50 including an angle a are shown. The pivoting between these positions is possible by operating the flyjib winch 52, and changing the flyjib cable length 51.

The flyjib 50 advantageously has a length of 20-30 meter. In the shown embodiment, the length is 30 meters. A whip hoist 55 extends to the outermost end of the flyjib 50. In fig. 6, an auxiliary hoist 58 is shown, extending to an outer end of the flyjib 50, capable of hoisting a nacelle 11 of a windmill.

Claims

CONCLUSIONS

A marine crane lifter (1) comprising:

a hull (2) with a transport deck (3), a plurality of lifting legs (5a-5f), each of the legs being movable in a vertical direction relative to the hull, the length of a leg being more than 50 meters, a plurality of lifting units (7a-7f) for moving the legs relative to the hull, and to bring the ship into an operational position where the legs touch the bottom of the sea (S) and the hull is substantially above water level (W) and a part of the lifting legs protrude above the transport deck;

a crane (20) mounted on the hull, comprising:

o a substantially hollow vertical column (21) with a foot (22) attached to the hull, and with a top (23), o a pivot bearing (25) extending around the vertical column (21) and a boom connecting element (26) and carries, so that the boom connecting element is rotatable about the column (21), a boom (24) pivotally mounted on the boom connecting element (26) about a substantially horizontal boom pivot axis (24P) so that the boom is on and is movable down, o a top winch (30) and an associated top cable (31) for pivoting the boom (24) up and down, o a hoisting winch (35) and an associated hoisting cable (36) for hoisting a load;

o a rotatable cable guide (40) arranged at the top of the column with a top hoisting block (41) for at least the top cable, wherein the cable guide (40) is mounted via an associated bearing construction, so that the rotatable cable guide supports the rotational movements of the boom around the boom. follows a vertical column and assumes substantially the same angular position as the boom, the top winch being positioned such that the top cable extends from the associated top winch up through the column to the rotating cable guide and from the rotating cable guide to the boom, characterized in, that the horizontal boom pivot axis (24P) is at a height relative to the transport deck that is greater than 35 meters, and wherein the rotating cable guide (40) is at a height relative to the transport deck that is greater than 60 meters.

The marine crane lifter according to claim 1, wherein the boom pivot axis (24P) falls within the footprint of the column, thereby enabling the crane to hoist loads weighing at least 1500 tons at a distance as close as 10 meters from a central axis of the column (C).

A marine crane lifter according to claim 1 or 2, wherein the center of gravity (G) of the crane including the boom is at a level below a horizontal plane extending through the boom pivot axis.

A marine crane lifter according to one or more of the preceding claims, wherein the boom has a length that is 40 meters.

A marine crane lifter according to any of the preceding claims, wherein the crane further comprises a boom arm (50) mounted at an outer end of the boom about a boom arm pivot axis (50P) that is parallel to the boom pivot axis so that the boom arm is pivotable up and down .

The marine crane lifter according to claim 5, further comprising a boom boom winch (52) and an associated boom boom cable (51) for pivoting the boom boom up and down, and wherein the boom boom winch is mounted on the boom link member (26).

7. Marine crane lifter according to claim 5 or 6, wherein the boom arm has a length of 20-30 meters.

A marine crane lifter according to any of the preceding claims, wherein the marine crane lifter (1) is configured to transport one or more straight masts (monopiles) and a current transformer for wind power purposes, wherein the crane is configured to handle such straight masts and a current transformer , in particular a current transformer with a weight between 1000 - 3000 tons and dimensions that are larger than 15x15 meters.

The marine crane lifter according to any of the preceding claims, wherein both the top winch (30) and the hoist winch (35) are positioned such that both the top cable (31) and the hoisting cable (36) extend from the associated winch up through the column (21) to the rotating cable guide (40) and from the rotating cable guide to the boom (24).

lü. Marine crane lifter according to one of the preceding claims, wherein a plurality of substantially vertical leg openings (6a-6f) extend through the hull, and wherein the lifting legs extend through the hull (2) via one of the vertical leg openings.

11. Operational method of a marine crane lifter according to one or more of the preceding claims at different water depths with associated operational positions of the ship, wherein the marine crane lifter transports a large object on the transport deck, for example a current transformer or straight mast for wind energy purposes, and wherein the crane is configured to be such a large

Object to handle, the method comprising the steps of:

gripping the large object by the hoisting cable;

picking up the large object from the transport deck;

overboarding the large object by rotating the boom of the crane over one of the lifting legs, and the engaged large object around the lifting leg.

X2 cm