A MOON POOL CONTROL DEVICE FOR A MARINE VESSEL

Abstract

A moon pool control device (5) for a marine vessel (1) comprises one or more closure members (8a,b) arranged for movement in the moon pool, between a moon pool closing position in a region of the moon pool opening (7), a moon pool open position, and a retracted position, and guiding means (14a,b; 15a,b; 17a,b; 18a,b) and motive means (9a,b; 10a,b; 22) configured for moving the closure member between said positions. In a particular embodiment, a pair of closure members (8a,b) and corresponding guiding means (14a,b; 15a,b; 17a,b; 18a,b) and motive means (9a,b; 10a,b; 22) are arranged on opposite lateral sides of the moon pool and configured to cooperate to close the opening (7) when both closure member s are in the closing position. The closure members comprise a continuous surface that forms a fluid barrier. The closure members may be retrieved onto the deck of the vessel.

Claims

1. A moon pool control device (5) for a marine vessel (1) having a moon pool (6) extending between a deck (2, 12) on the vessel and an opening (7) in a hull portion (4) of the marine vessel, characterized by one or more closure members (8a,b) arranged for movement in the moon pool, between a moon pool closing position in a region of the moon pool opening (7), a moon pool open position, and a retracted position in a region of said deck (2, 12), and guiding means (14a,b, 15a,b, 17a,b, 18a,b) and motive means (9a,b, 10a,b, 22) configured for moving the closure member between said positions.

2. The moon pool control device of claim 1, wherein the guiding means (14a,b, 15a,b, 17a,b, 18a,b) extend between a region of said opening (7) and a region of said deck (2, 12).

3. The moon pool control device of claim 1, wherein a first set of guiding means (14a,b, 15a,b) are configured to provide support for the closure member when the closure member is in the closing position.

4. The moon pool control device of claim 1, wherein the closure member (8a,b) comprises locking structures (25a, 26a, 25b, 26b) configured for releasable interaction with mechanical locks (35, 36) when the closure member is in the moon pool closing position.

5. The moon pool control device of claim 1, further comprising a carrier (16a,b) hingeably connected to each closure member (8a,b), and wherein the carrier is movably connected to a second set of guiding means (17a,b, 18a,b) and to the first motive means (10a,b).

6. The moon pool control device of claim 5, wherein the closure member is hingeably connected to the carrier at a first end, and a second, opposite, end comprises a leading edge (32a,b).

7. The moon pool control device of claim 6, wherein the leading edge comprises a recessed portion (29a,b).

8. The moon pool control device of claim 1, wherein a pair of closure members (8a,b) and corresponding guiding means (14a,b, 15a,b, 17a,b, 18a,b) and motive means (9a,b, 10a,b, 22) are arranged on opposite lateral sides of the moon pool and configured to cooperate to close the opening (7) when both closure members are in the closing position.

9. The moon pool control device of claim 1, wherein the closure member comprises a continuous surface, preferably of a metal material, that forms a fluid barrier.

10. The moon pool control device of claim 8, further comprising locking and support means (20, 21) arranged in a region of the opening (7) and having support means (20a,b) configured for supporting each closure member (8a,b) in a region of the closure member leading edge (32a,b).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] These and other characteristics of the invention will become clear from the following description of a preferential form of embodiment, given as a non-restrictive example, with reference to the attached schematic drawings, wherein:

[0027] FIG. 1 is a side view of a ship being equipped with an embodiment of the invented device;

[0028] FIG. 2 is a sectional view towards the section A-A shown in FIG. 1;

[0029] FIG. 3 is a perspective cut-out, and partly transparent, drawing of the invented device, with the moon pool hatches in a closed position;

[0030] FIG. 4 is in many respects similar to FIG. 3, except that some components have been removed to illustrate certain aspects of the invention;

[0031] FIG. 5 is a side view of the lower portion of the device as illustrated in FIG. 4;

[0032] FIG. 6 is a top view of the device as illustrated in FIG. 4;

[0033] FIG. 7 is a perspective view of a portion of the lower right-hand corner of FIG. 4;

[0034] FIG. 8 is in many respects similar to FIG. 4, showing the moon pool hatches in an open position;

[0035] FIG. 9 is a perspective cut-out, and partly transparent, drawing of the invented device, with the moon pool hatches in an open and retracted position;

[0036] FIG. 10 corresponds to the lower portion of FIG. 4, and shows an alternative configuration of the moon pool hatches;

[0037] FIG. 11 illustrates a locking clamp in an open (unlocked) position; and

[0038] FIG. 12 illustrates the locking clamp in a locked (clamping) position.

DETAILED DESCRIPTION OF A PREFERENTIAL EMBODIMENT

[0039] The following description may use terms such as “horizontal”, “vertical”, “lateral”, “back and forth”, “up and down”, “upper”, “lower”, “inner”, “outer”, “forward”, “rear”, “top”, “bottom”, etc. These terms generally refer to the views and orientations as shown in the drawings and that are associated with a normal use of the invention. The terms are used for the reader's convenience only and shall not be limiting.

[0040] FIG. 1 shows the invented device 5 installed on a ship 1 having a moon pool 6 extending through the ship's hull 4 from an upper deck 2 to the hull bottom 19. A hangar 3 (e.g. for an ROV) is arranged above the moon pool. Referring additionally to FIG. 2, the moon pool bottom opening 7 is closed by a pair of hatches 8a,b, substantially flush with the hull bottom, in a manner which will be described in detail below. FIG. 2 also shows a pair of winches 9a,b, and sets of wires 10a,b extending between the each of the winches and a respective hatch.

[0041] The invented device is shown in more detail in FIG. 3. The winches 9a,b, which in the illustrated embodiment is arranged on a lower deck 12, immediately below the main deck 2, are connected via respective pairs of wires 10a,b to respective frame structures 16a,b, referred to hereinafter as carriers. Referring additionally to FIG. 7, each respective wire pair extends between its winch, via a plurality of sets of pulleys 22, and a respective attachment point 31 on the respective carrier 16a,b. As shown in the figures, pulleys are arranged on the (inside) hull bottom, near the moon pool opening, on the lower deck 12 and on the moon pool wall 13. Referring additionally to FIGS. 4, 6 and 7, where certain components have been removed in order to better illustrate other components, each carrier 16a,b is movably supported via rollers 27 by a pair of carrier guides 17a, 18a and 17b, 18b extending between the moon pool bottom opening and a region of the main deck 2 or lower deck 12. Each winch is thus capable of moving its respective carrier 16a,b—supported and guided by the carrier guides—up and down in the moon pool. The power supply, control, and operation of the winches are per se known in the art and need therefore not be described in more detail here.

[0042] A first moon pool hatch 8a is hinge-connected to the first carrier 16a via a pair of bolts 28. A second moon pool hatch 8b is hinge-connected to the second carrier 16b via a pair of bolts 28. The hatches 8a,b are shaped and dimensioned to close the moon pool bottom opening 7 when they are in the positions shown in e.g. FIGS. 3 to 7. The hatches are made of a strong and durable material, such as steel, and comprise preferably welded box structures to provide strength and stiffness.

[0043] Each hatch 8a,b comprises rear portion (which is hinge-connected to the carrier via the bolts 28) and a forward portion, preferably comprising a gasket 30a,b, as illustrated by e.g. FIG. 6. The forward portion of each hatch comprises a recessed portion 29a,b arranged and configured such that a hole is formed when the hatches are in the closed position. Thus, the hatches 8a,b form a firm barrier at the moon pool bottom opening, preventing ingress of seawater. The hole may be temporarily plugged, if desired, by a plug device 33, illustrated schematically in FIG. 10. The plug device 33 may comprise means for it to be lowered from and retrieved to the decks 2, 13. FIG. 10 also indicates optional adjustments means 34a,b, whereby the hatch recesses 29a,b (and hence the hole size) may be adjusted, for example remotely from a location on deck 2.

[0044] Each hatch 8a,b is supported and guided in a region of its forward portion via respective pairs of rollers 23 in respective guide structures 14a,b, 15a,b, hereinafter referred to as hatch guides. A hatch guide 14a,b, 15a,b is arranged generally in each corner of the moon pool. Thus, a first pair of hatch guides 14a, 15a is arranged on a right-hand side of the moon pool, and a second pair of hatch guides 14b, 15b is arranged on a left-hand side of the moon pool (as seen in FIG. 3). Each hatch guide has a first portion which extends along the (inside) hull bottom from a respective central hatch lock 20, 21, a second portion which extend the length (i.e. height) of the moon pool to a region of the main and lower decks, and a curved portion interconnecting the first and second portion. The hatch locks 20, 21 are arranged one on each side of the moon pool bottom opening and are configured to receive a hatch leading edge 32a,b. Referring to FIG. 5, the hatch locks comprise an upper abutment portion 20a, preventing upward movement of the hatches when they are in the closed position, and a lower abutment portion 20b, preventing downward movement of the hatches when they are in the closed position.

[0045] It should be understood that additional mechanical locks, as known in the art per se, may be provided in the moon pool to releasably engage with locking interface structures 25a, 26a, 25b, 26b arranged at the hatches' rear portion when the hatches are in the closed position. FIG. 11 and FIG. 12 illustrate one such variant, in which a movable locking clamp 35 is provided in the moon pool side to press down (and clamp) the hatch 8b when it is in the closed position. The clamp 35 is operated via a known actuation and control means (not shown), via e.g. a push-rod 36. FIG. 11 shows the locking clamp 11 in an open (unlocked) position, and FIG. 12 shows the locking clamp 35 in a locked (clamping) position.

[0046] In operation, each of the hatches 8a,b may be moved between: [0047] a moon pool closing position (shown in e.g. FIG. 3); [0048] a moon pool opening position (shown in FIG. 8), and [0049] a retracted position (shown in FIG. 9)

[0050] Although not illustrated, it should be understood that extensions may be connected to the upper end of each carrier guide, whereby the carriers may be hoisted further up (e.g. by a crane) such that the carriers and hatches are easily accessible for service personnel working on the deck 2.

[0051] In should be understood that the hatches may be operated individually or simultaneously, for example having one hatch in the moon pool closing position and the other hatch in the open or retracted position. The moon pool bottom opening 7 may thus selectively be fully closed, partly open, and fully open. When both hatches are in the closing position, cables and umbilicals may be run through the hole formed by the recessed portions 29a,b. Thus, an ROV may be operated from the ship even when the hatches are in the closed position, while the piston effect is avoided and the above mentioned turbulence-induced drag is virtually eliminated.

[0052] When the hatches are in the retracted position (FIG. 9) they are easily accessible from the main deck 2 or the lower deck 12, and may be removed from their respective carrier for repair, refurbishment or replacement. The carriers may also be disconnected from their guides in this position. Although not illustrated, it should be understood that the carrier guides and hatch guides may be extended beyond the main deck, if desirable or practical.

[0053] It should be understood that the wire-and-winch arrangement described above may be replaced by other motive means, such as chains, sprockets, rack-and-pinion, without deviating from the scope of the invention. The moon pool may also be furnished with panels and covers in order to protect the wires, pulleys, etc.

[0054] Although the invented hatch device is particularly useful in a moon pool on an ROV handling ship, it should be understood that the invention is applicable to any moon pool or similar construction on a marine vessel.

[0055] Although the invention has been described as having a pair of hatches of the same size that together close the moon pool bottom opening, it should be understood that the invention also applies to embodiments where the hatches have different sizes. The invention also applies to an embodiment having only one hatch. In that case the hatch guides are extended on both sides of the moon pool bottom opening and the singular hatch preferably extends across the entire moon pool bottom opening when in the closing position.