Marine crane vessel and method of operation

Abstract

A marine vessel and a method of operation of such a marine vessel include a crane with a boom including a main boom section and a jib section and a variable length stay mechanism. The lattice boom is movable from a hoisting position into a parking position by a routine including operating the variable length stay mechanism allowing the jib section to fold towards the main boom section. The crane is provided with a fixation device adapted to establish fixation of the jib section relative to the main boom section in a folded position. A boom rest is mounted on the hull. The routine further includes operating the luffing assembly to position the jib member of the folded jib section, fixated to the main boom section, in the parking position onto the boom rest.

Claims

1. A marine vessel comprising: a hull; a ring bearing mounted on the hull; and a crane, the crane comprising: a revolving superstructure mounted upon said ring bearing; a boom pivotally mounted to the revolving superstructure, the boom comprising: a main boom section, comprising: a boom member, the lower end of the boom member being pivotally mounted about a pivot axis to the superstructure; and a main boom strut, an end of the main boom strut being mounted to an upper end of the boom and extending essentially perpendicular to the boom member; and a boom stay extending between the main boom strut and a lower portion of the boom member; a jib section mounted pivotably about a pivot axis to the main boom section, the jib section comprising: a jib member, an inner end of the jib member being pivotably mounted about the pivot axis to the upper end of the boom member; a jib strut, an end of the jib strut being mounted to the inner end of the jib member and extending essentially perpendicular to the jib member; and a jib stay extending between the jib strut and the jib member; and a variable length stay mechanism provided between the main boom strut and the jib strut; a luffing assembly comprising a luffing winch mounted to the superstructure and a luffing cable extending between the superstructure and the main boom section; and a hoist winch, a hoist cable and an object suspension device, the hoist cable extending from the hoist winch along the main boom section and the jib section to the object suspension device, wherein the boom is movable from a hoisting position into a parking position by a routine comprising: keeping the boom member in a raised position; operating the variable length stay mechanism allowing the jib section to fold towards the main boom section, wherein the crane is provided with a fixation device adapted to establish fixation of the jib section relative to the main boom section in a folded position; fixing the jib section relative to the main boom section by the fixation device to maintain the jib member and the boom member essentially parallel in the folded position, wherein a boom rest is mounted on the hull; and operating the luffing assembly to position the jib member of the folded jib section, fixated to the main boom section, in the parking position onto the boom rest.

2. The marine vessel according to claim 1, wherein the fixation device is provided at the main boom section.

3. The marine vessel according to claim 2, wherein the fixation device is able to fix the jib section relative to the main boom section by receiving the object suspension device or part thereof.

4. The marine vessel according to claim 1, wherein the fixation device is able to fix the jib section relative to the main boom section by receiving the object suspension device or part thereof.

5. The marine vessel according to claim 1, wherein the fixation device comprises complementary fixation members provided at both the jib section and the main boom section.

6. The marine vessel according to claim 1, wherein in said step of keeping, the boom member is at a forwardly angled position, and wherein during said step operating the variable length stay mechanism, the luffing assembly is operated to position the boom member in a vertical position, while allowing the jib section to fold towards the main boom section.

7. The marine vessel according to claim 1, further comprising a control device programmed to perform at least the steps of operating the variable length stay mechanism and operating the luffing assembly of the routine automatically.

8. The marine vessel according to claim 1, wherein the boom rest is mounted on the hull about vertical leg openings, said boom rest being structurally anchored to the hull, independently of a leg and an elevating unit thereof.

9. Method A method of operation of the marine vessel according to claim 1, for moving the boom of the crane from a hoisting position into a parking position, comprising the steps of: keeping the boom member in a raised position; operating the variable length stay mechanism allowing the jib section to fold towards the main boom section; fixing the jib section relative to the main boom section by the fixation device to maintain the jib member and the boom member essentially parallel in the folded position; and operating the luffing assembly to position the jib member of the folded jib section, fixated to the main boom section in the parking position onto the boom rest.

10. The method according to claim 9, wherein in the step of keeping, the boom member is at a forwardly angled position, and wherein during the step of operating the variable length stay mechanism, the luffing cable is operated to position the boom member in a vertical position, while allowing the jib section to fold towards the main boom section.

11. A method of operation of the marine vessel according to claim 1, for moving the boom of the crane from a parking position into a hoisting position, comprising the steps of: operating the luffing assembly to move the jib section fixated to the main boom section from the parking position onto the boom rest to a vertical position wherein the jib member and the boom member are essentially parallel in the folded position; detaching the jib section from to the main boom section; operating the variable length stay mechanism allowing the jib section to pivot away from the main boom section until the jib section is at a hoisting position; and operating the luffing device to position the main boom section in the hoisting position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

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

(2) FIG. 1a represents a side view of a jack-up type marine vessel according to the invention in a hoisting position;

(3) FIG. 1b represents a detail of the crane of FIG. 1a,

(4) FIG. 1c represents a further detail of the crane of FIG. 1b,

(5) FIG. 1d represents a side view of a jack-up type marine vessel of FIG. 1a in an alternative hoisting position;

(6) FIG. 2a represents a side view of the jack-up type marine vessel of FIG. 1 during the routine of moving the lattice boom from the hoisting position into a parking position, wherein the latticed boom member is in an essentially vertical position;

(7) FIG. 2b represents a side view of the jack-up type marine vessel of FIG. 1 during a possible routine of moving the lattice boom from the hoisting position into a parking position, wherein the latticed boom member is in a forwardly angled position;

(8) FIG. 2c represents a further step of the routine of FIG. 2b;

(9) FIG. 2d represents yet a further step of the routine of FIG. 2b;

(10) FIG. 3 represents a side view of the jack-up type marine vessel of FIG. 1 with the lattice boom in the parking position;

(11) FIG. 4 represents a top view of the jack-up type marine vessel of FIG. 3 with the lattice boom in the parking position.

DETAILED DESCRIPTION OF EMBODIMENTS

(12) In FIGS. 1a-4, an exemplary jack-up type marine vessel 1 is shown, comprising a hull 2 and a plurality of generally vertical leg openings 5a, 5b through the hull. Here, the hull is embodied as a vessel. Alternatively, the hull is embodied as a barge or a platform or a semi-submersible or the like. The shown hull 2 comprises a deck 3.

(13) The hull 2 comprises a plurality of generally vertical leg openings 5a, 5b through the hull. These leg openings are spaced about the hull. Here, two of such openings are visible, while the vessel comprises four of such openings. Generally, a hull comprises 3 or 4 of such openings to provide a stable jack-up type marine vessel.

(14) A plurality of legs 4a, 4b extend through the hull 2 via the one of said vertical leg openings 5a, 5b; each of which legs is movable in a vertical direction with respect to the hull. A plurality of elevating units 6a, 6b is positioned at the vertical leg openings for changing the elevation of the hull relative to the legs, each of the elevating units being adapted to lift the hull when the legs engage the seabed. In the side view, again, only two of such legs are visible, while the vessel comprises four of such legs.

(15) In the legs, openings 4g, 4h are visible which are able to receive pins (not visible) to fixate the hull relative to the legs.

(16) In embodiments, the elevating units are adapted to lift the hull free of the water surface when the legs engage the seabed. It is also conceivable that the hull is semi-submersible and that the elevating units are able to position the hull partially under water when the legs engage the seabed.

(17) In the shown embodiment, jack-up housings 9, 41 are provided on deck 3 extending a distance above deck and housing the vertical leg openings 5a, 5b respectively, and the lifting units 6a, 6b respectively. Legs 4a, 4b respectively are able to extend through these jack-up housings 9, 41, as visible in the drawings.

(18) In the shown embodiment, a ring bearing 10 is mounted on the jack-up housing 9 which is mounted on the hull 2 about the vertical leg openings 5a. Said ring bearing 10 is structurally anchored to the hull 2, independently of the leg 4a and its elevating unit 6a.

(19) A crane 20 is mounted upon said ring bearing 10. The crane 20 comprises a revolving superstructure 21 mounted upon said ring bearing 10 around the leg 4a. The superstructure 21 has an elongated A-shaped frame, also referred to as gantry. The height of the superstructure is for example about 25 meters, for a lattice boom of about 100-120 meters. The superstructure 21 extends about leg 4a and adjacent elevating unit 6a. The superstructure 21 is rotatable upon the ring bearing 10 and thus around the leg 4a, independently of the leg and its elevating unit. Such a crane-type is known in the art as an around the leg-crane.

(20) The type of crane 20, i.e. a lattice boom crane with a jib is also well known in the art and commonly applied, e.g. in crawler cranes. The jib is sometimes also referred to as a fly-jib, and is generally provided to obtain an increased length of the lattice boom of the crane.

(21) The crane 20 comprises a lattice boom pivotally mounted to the revolving superstructure 21, here in particular to a foot portion of revolving superstructure. The lattice boom comprises a main boom section 25 and a jib section 26 mounted pivotably about a pivot axis P to the main boom section. Details of the crane are shown in FIGS. 1b and 1c.

(22) The main boom section 25 comprises a latticed boom member 25a, the lower end 25a of which is pivotally mounted about a pivot axis 22 to the superstructure 21, here to a foot portion of the superstructure 21. The boom section 25 further comprises a main boom strut 25b, one end 25b of which is mounted to an upper end 25a of the boom and extends essentially perpendicular to the boom member. The boom section 25 further comprises a boom stay 25c extending between the main boom strut 25b, in the shown embodiment from the opposed end 25b of the main boom strut, and a lower portion of the boom member 25.

(23) Here, the boom stay is a fixed boom stay of fixed length. Possibly, a boom stay of variable length is applied. Accordingly, the main boom section comprises a generally triangular shape, in particular a rectangled triangle formed by boom member 25a, main boom strut 25b and boom stay 25c.

(24) In the shown embodiment, a cylinder 27 is provided between the boom member 25a and the main boom strut 25b to provide structural strength.

(25) The jib section 26 is mounted pivotably about a pivot axis P to the main boom section. The latticed boom member 25a comprises a front face 25e, opposite the side of the main boom strut 25b and the boom stay 25c. The pivot axis P advantageously extends forward of this front face 25e, allowing the jib section to be fully folded against the main boom section 25.

(26) The jib section 26 comprises a latticed jib member 26a, an inner end 26a of which is pivotably mounted about pivot axis P to the upper end 25a of the latticed boom member. The jib section 26 further comprises a jib strut 26b, an end 26a of which is mounted to the inner end 26a of the jib member and extends essentially perpendicular to the jib member 26a. The jib section 26 further comprises a jib stay 26c extending between the jib strut 26b, in the shown embodiment from the opposed end 26b of the jib strut 26b, and the jib member 26a. Here, the jib stay is a fixed jib stay of a fixed length. It is also conceivable that the jib stay has a variable length. Accordingly, the jib section 26 comprises a generally triangular shape, in particular a rectangled triangle formed by jib member 26a, jib strut 26b and jib stay 26c. In the shown embodiment, a cylinder 29 is provided between the jib member 26a and the jib strut 26b to provide structural strength.

(27) A variable length stay mechanism 28 is provided between the jib section 26 and the main boom section 25, in particular between the main boom strut 25b and the jib strut 26b. In the shown embodiment, the variable length stay mechanism 28 is provided between an end 25b of the main boom strut 25b and end 26b of the jib strut 26b.

(28) In the shown embodiment, the variable length stay mechanism 28 comprises two sheaves 28a, 28b, connected respectively to end 25b of the main boom strut 25b and end 26b of the jib strut 26b. Between the sheaves a cable 28c of adjustable length is provided. Preferably a winch, not shown, is provided to operate the variable length stay mechanism 28.

(29) The crane 20 further comprises a luffing assembly with a luffing winch 31 mounted to the superstructure and a luffing cable 32 extending between the superstructure 21 and the main boom 25. The luffing assembly is provided to position the main boom section of the crane in an appropriate hoisting position. There is a correlation between the maximum load that can be hoisted and the position of the main boom section. Generally, the closer the boom member is to the vertical, the larger the load that it can hoist. In the hoisting position shown in FIG. 1d, the maximum load may be e.g. 20,000 kg, while the maximum load in the position shown in FIG. 1a may for example be 100,000 kg.

(30) It is advantageous, as shown, for the luffing cable 32 to extend between a top end of the superstructure 21, here via a sheave 33 provided at the top end, as this is advantageous for the interplay of forces to position the main boom section 25.

(31) The crane 20 further comprises a hoist winch 37, a hoist cable 35 and an object suspension device 36. In the shown embodiment, the hoist winch 37 is also mounted to the superstructure 21. The hoist cable 35 extends from the hoist winch 37 along the main boom section 25 and the jib section 26 to the object suspension device 36. In the shown embodiment, the hoist cable 35 extends from hoist winch 37, provided at one end of the A-shaped superstructure 21, over a sheave 38a provided at an upper end of the A-shaped superstructure 21 and via sheave 38b provided at the opposed lower end of the A-shaped superstructure, via the lower end 25a of the boom member to its upper end 25a, via the main boom strut 25 to end 25b thereof, along the variable length stay mechanism 28 and then along the jib stay 26c to an outer end 26a of the jib member 26a.

(32) Here, the outer end 26a comprises a departing sheave 26e for the hoist cable 35, to which object suspension device 36 is attached. The outer end 26a further comprises a departing sheave 26f for a whip hoist cable (not shown) to which whip hoist 24 is attached. The capacity, also referred to as the safe working load, of the whip hoist is generally 10-30% of that of the hoist system with hoist winch 37, hoist cable 35 and object suspension device 36. For example, the safe working load of the (main) hoist in an essentially vertical position of the lattice boom is 100,000 kg, with a lattice boom of about 100 meters length, while the capacity of the whip hoist in this position is 20,000 kg. The safe working load of the (main) hoist decreases to 20,000 kg in a position wherein the object suspension device is at a radius of 60 meters away from the revolving superstructure 21.

(33) A boom rest 40 is mounted on the jack-up housing 41 which is mounted on the hull 2 about the vertical leg openings 5b. Said boom rest 40 is structurally anchored to the hull 2, independently of the leg 4b and its elevating unit 6b. Advantageously, a padded structure 42 is provided to receive the lattice boom.

(34) In the shown embodiment, the crane, here in particular the latticed boom member 25a, in particular the front face 25e thereof, is provided with a fixation device 25d adapted to establish fixation of the jib section 26 relative to the main boom section 25 in a folded position. The fixation device 25 is here embodied as an eyelet, adapted to receive a hook 36a of the object suspension device 36, as is visible in the parking position of FIG. 3.

(35) According to the present invention, the lattice boom is movable from a hoisting position, as visible in FIG. 1, into a parking position as shown in FIGS. 3 and 4, by a routine comprising the following steps: a. keeping the latticed boom member 25a in a raised position, such as the vertical position as shown in FIG. 2a; b. operating the variable length stay mechanism 28 allowing the jib section 26 to fold towards the main boom section 25 about pivot point P, under the influence of gravity; c. fixing the jib section 26 relative to the main boom section 25 by the fixation device 25d to maintain the jib member 26a and the boom member 25a essentially parallel in the folded position; d. operating the luffing assembly to position the jib member of the folded jib section, fixated to the main boom section in the parking position onto the boom rest 40.

(36) In embodiments, it may be advantageous to have a routine wherein in step a. the latticed boom member is at a forwardly angled position, such as shown in FIG. 2b. In this drawing, the variable length stay mechanism 28 has allowed the jib section 26 to fold towards the main boom section 25 about pivot point P. In FIG. 2c, it is visible that in the shown embodiment, hook 36a of the object suspension device 36 has been attached to the fixation device 25d on the latticed boom member 25a. The hoist cable 35 spans the distance between the fixation device 25d and the sheave 26e on the jib member 26a. By operating the hoist cable 35 via winch 37, the jib section 25 is allowed to pivot towards main boom section 25, as shown in FIG. 2d.

(37) From this folded position shown in FIG. 2d, the luffing assembly is operated to position the jib member of the folded jib section, fixated to the main boom section, in the parking position onto the boom rest 40 as shown in FIG. 3.

(38) Yet alternatively, not shown, when the latticed boom member is at a forwardly angled position, it is possible to during step b. operate the luffing cable position the latticed boom member in a vertical position, while allowing the jib section to fold towards the main boom section.

(39) It is advantageous if the jack-up type marine vessel further comprises a control device 42 programmed to perform at least the steps of operating the variable length stay mechanism 28 and operating the luffing assembly of the routine automatically.

(40) As visible in FIG. 3, the height of the boom rest 40 is such that the jib stay is essentially horizontal in the parking position, and the main boom strut 25b and jib strut 26b are in an essentially vertical position, in line with each other. From FIG. 3 follows that in the shown embodiment, the length of the latticed jib member 26a essentially equals that of the length of the hull 2, here approximately 60 meters. The length of the latticed jib member 26a, here approximately 40 meters, adds up to an overall length of the lattice boom of the crane of 100 meters, while not protruding outside the footprint of the hull of the vessel during sailing.

(41) As visible in FIG. 3, in the folded position of the jib section 26 relative to the main boom section the latticed boom member 25a and the latticed jib member 26a include an angle of less than 10, in particular less than 5.

(42) As visible in FIG. 4, the folded jib section 26 and main boom section 25 rest onto the boom rest offset from the leg 4b in the leg opening 5b.