US3918380A

US3918380A - Closable well in hull of deep ocean mining vessel

Info

Publication number: US3918380A
Application number: US479097A
Authority: US
Inventors: John R Graham; Robert C Crooke
Original assignee: Global Marine Inc
Current assignee: Global Marine Inc
Priority date: 1974-06-13
Filing date: 1974-06-13
Publication date: 1975-11-11
Anticipated expiration: 1992-11-11

Abstract

A surface vessel for deep ocean mining having a large opening through the center of the hull which can be closed from the sea by means of large movable gates. Mining machinery can be stowed in this center well and, with the gates closed, the well can be pumped dry, providing a maintenance area. With the gates open and the well flooded, the mining machinery can be lowered to, or raised from, the floor of the ocean. The well is closed by two gates, which move fore and aft relative to each other and slide in guides mounted beneath the hull of the ship. The gates are provided with segmented compartments into which air can be pumped to increase their buoyancy. The buoyant gates press upwardly against the bottom of the hull to seal off the well area from the sea. To open the gates, the seal is broken by bleeding the air and allowing sea water to flood the segmented compartments.

Description

United States Patent Graham et al.

1 CLOSABLE WELL IN HULL OF DEEP OCEAN MINING vEssEL [73] Assignee: Global Marine Inc., Los Angeles,

Calif.

Filed: June 13, 1974 Appl. No.: 479,097

[56] References Cited UNITED STATES PATENTS 6/1913 Reid 114/36 12/1958 Hoitt et a1 114/173 FOREIGN PATENTS OR APPLICATIONS 1,510.126 France 114/05 D Nov. 11, 1975 Primary Eraminer-Trygve M. Blix Assistant E.raminer$herman D. Basinger Attorney. Agent, or FirmChristie, Parker & Hale [5 7 ABSTRACT A surface vessel for deep ocean mining having a large opening through the center of the hull which can be closed from the sea by means of large movable gates. Mining machinery can be stowed in this center well and, with the gates closed, the well can be pumped dry, providing a maintenance area. With the gates open and the well flooded, the mining machinery can be lowered to, or raised from, the floor of the ocean. The well is closed by two gates, which move fore and aft relative to each other and slide in guides mounted beneath the hull of the ship. The gates are provided with segmented compartments into which air can be pumped to increase their buoyancy. The buoyant gates press upwardly against the bottom of the hull to seal off the well area from the sea. To open the gates, the seal is broken by bleeding the air and allowing sea water to flood the segmented compartments.

7 Claims, 4 Drawing Figures US. Patent Nov. 11, 1975 Sheet 1 of3 3,918,380

& ww N w in; E M u U.S. Patent Nov. 11, 1975 Sheet 3 013 CLOSABLE WELL IN HULL OF DEEP OCEAN MINING VESSEL FIELD OF THE INVENTION This invention relates to a deep ocean mining ship, and more particularly, to a mining ship havinga docking well which is opened and closed to the sea by gates.

BACKGROUND OF THE INVENTION In copending application Ser. No. 479,091, filed June 13, 1974, entitled Apparatus for Raising and Lowering Pipe String From a Floating Vessel, filed in the names of Robert Curtis Crooke and Abraham Person,

as inventors, and assigned to the same assignee as the present invention, there is described a deep ocean mining vessel in which heavy mining equipment can be raised and lowered between the vessel and the ocean floor. Because the subsea mining equipment is heavy andbulky, it is desirable to raise and lower the equipment through the center of the vessel. Unlike some oil drill ships, which provide a small opening extending through the center of the vessel to permit drill pipe to be raised and lowered from the surface vessel, the deep ocean mining vessel requires a well sufficiently large to store the mining machinery within the ship while in transit to various mining locations and port.

SUMMARY OF THE INVENTION The present invention is directed to a surface vessel having a large center well, the bottom of which can be opened and closed by a pair of sliding gates movable horizontally along the bottom-of the vessel. The gates are provided with water-tight compartments from which air or water can be added or removed to control the buoyancy of the gates. When closed, the gates seal off the well from the sea, permitting the docking well to be pumped dry. By pumping air into the gate compartments, the gates are forced more tightly against the bottom of the vessel to form an efficient positive seal.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the invention, reference should be made to the accompanying drawings, wherein: I

FIG. 1 is a side elevational view of a ship incorporating the features of the present invention;

FIG. 2 is a fragmentary sectional view of the docking well;

FIG. 3 is a plan view of the gates and associated guide structure; and

FIG. 4 is a fragmentary sectional view showing details of the gate drive and support mechanism with the gate partially open.

DETAILED DESCRIPTION Referring to FIG. 1, the numeral indicates the general outline of the hull of a ship designed for deep ocean mining, such as described in detail in the aboveidentified copending application. The midships portion of the vessel has a large open well 12 which extends vertically through the hull 16 from the main deck 14 and through the bottom of the vessel. The well 12 extends fore and aft approximately a third of the total length of the vessel and is essentially rectangular in shape enclosed by vertical sidewalls l7, and front and rear

vertical endwalls

19 and 21, and

bottom gates

20 and 22. The top of the well is open.

Although not specifically shown in the drawings, heavy lift equipment for raising and lowering mining machinery or other equipment from the well 12 to the bottom of the ocean spans the top of the well between the portions of the top deck 14 on either side of the well 12, such as described in the aboveidentified copending application. The mining or other equipment (not shown) is docked inside the well while the ship is in transit.

The bottom of the well 12 is provided with a pair of

gates

20 and 22 which close the well opening at the bottom of the ship. The respective gates move horizontally in a fore and aft direction along the bottom of the ship. To this end, the

gates

20 and 22 are movable along a pair of parallel

gate guide members

24 and 26 extending in a fore and aft direction and secured to the bottom of the vessel on either side of the well opening. As best seen in FIG. 4, each guide member includes a vertical guide surface 30 extending downwardly from the bottom 16 of the vessel to a horizontal guide surface 32 which projects inwardly from the surface 30. Each of the

gates

20 and 22 include parallel flat side plates 34. To each plate is secured projecting guide and sealing assembly 36. The guide assembly 36 includes a boxshaped girder 37 extending the length of the gate side plates. A plurality of rollers 38 are journaled within the box girder for rotation about a horizontal axis, the rollers 38 projecting outside the girder are in rolling contact with the horizontal surface 32 of the

guide members

24 and 26. In addition, a plurality of rollers 40 are journaled in the box girder 37 of the guide assembly 36 for rotation about a vertical axis, the rollers 40 having rolling contact with the vertical surfaces 30 of the

guide members

24 and 26.

The

gates

20 and 22 are constructed of multiple transverse bulkheads 42 covered with flat top plates 44, which form the bottom of the well with the two gates closed and bottom plates 46 which are exposed to the sea. As shown by the cross section of FIG. 4, the bottom plate is angled upwards slightly from the middle of the plate to the side plate 34. This lends stability both to the movable gate and to the vessel itself. As shown in FIG. 3, the bulkheads 42 are braced by fore and aft spacers 47 to form a rectangular cellar structure. The interior of the gates are divided into separate watertight compartments for ballast, nine such compartments per gate being shown. Any combination of compartments can be opened to the sea through the bottom plates 46. The buoyancy of the gates is controlled by displacing the sea water from selected ballast compartments with compressed air. To increase buoyancy, air is pumped into the gate compartments. To decrease the buoyancy, the air is released, allowing the sea water to re-enter the compartments. To this end several air valves 50 are mounted below the top plate 44, the valves 50 being connected to respective compartments within the gates by suitable pipe connections 51. These valves can be operated from the main deck to control the flow of compressed air into or bleed air out of the gate compartments.

To open and close the gates, each gate is provided with two

gear racks

52 and 54 extending down the center for the full length of the gate. As shown in FIG. 4, the racks are recessed in the top plates 44 of the gates so as not to interfere with the movement of the gates outwardly beneath the bottom of the ship. The drive mechanism for opening and closing each of the gates includes a pair of gears 56 which engages the

racks

52 and 54. Each of the gears 56 rotates on a drive shaft 58. Since the gear and rack are exposed to the sea water when the gates are opened, the drive gear 56 is enclosed within a water-tight compartment 60. The shaft 58 extends through the wall of the compartment 60 through a sealed packing gland and bearing 62. Thus the sea water is confined to the interior of the compartment 60. The shaft 58 is journaled at its other end in a bearing block 64. Rotation is imparted to the gear 56 by a suitable hydraulic motor 66 through a gear reduction drive 68. The output of the gear drive 68 is coupled through a chain drive 70 to a sprocket 72 on the shaft 58. Four such drive assemblies are provided, one for each rack on the respective gates and 22.

When moved to their closed positions, the

gates

20 and 22 engage stops 74 and 76 projecting from the vertical surface of

respective guide members

24 and 26. The stops engage recesses 78 and 80 in the gate 20, and 82 and 84 in the gate 22. The abutting end of the gate 20 is provided with a seal 86 (see FIG. 2) which provides a watertight interface when it engages the surface of the abutting end of the gate 22 with the gates closed. In addition, a flexible seal is secured around the upper perimeter of the gates, as indicated at 88 and 90, respectively. As seen in FIG. 4, the sealing

members

88 and 90 project above the top plate 44 of the gate toward the bottom of the vessel. After the gates are moved to the closed position, the ballast compartments in the gates are filled with air through the valves 50 so as to provide positive buoyancy to the gates. This causes the gates to lift off the horizontal surfaces 32 of the guides thereby pushing up against the bottom of the vessel, bringing the sealing

members

88 and 90 into contact with the bottom of the vessel around the periphery of the docking well. This compresses the seal strips against the bottom of the vessel, completely sealing off the docking well from the intrusion of sea water. The docking well can then be pumped dry by conventional pumps (not shown) to provide a drydock storage area for the mining equipment. I

When the mining equipment is to be lowered to the ocean floor, sea water is pumped in until the well is partially flooded. Air is then released from the compartments in the gates, allowing sea water to re-enter the ballast compartments in the gates. The combined force of the water in the well and the negative buoyancy of the gates thus cause the gates to drop down on the rollers 38 on the guide surfaces 32. The amount of vertical movement of the gates is relatively small and well within the normal tolerances of the engaging teeth of

racks

52 and 54 and gears 56. The seal thus broken, the gates can then be rolled back on the guides to the open position. Stops are provided at the ends of

guides

24 and 26 which prevent the gates from being driven too far outwards in the guides. The stops may be provided with suitable sensing means for interrupting automatically the drive mechanism when the gates move to a fully open position.

When the gates are closed mechanical latches 100 are lowered into recesses 104 in the

gates

20 and 22. Lowering and raising of these gate locking latches is accomplished by a wire line 101 attached to winch 102 4 located port and starboard of the well at the main deck. The latches, of course, must be released before the gates are opened.

What is claimed is:

l. A vessel comprising a hull, an open well extending vertically through the hull, and gate means for opening and closing the bottom of the well, said means including means for sealing off the bottom of the well when the gate means is closed, said means for opening and closing the well including means slidably supporting the gate means for movement horizontally beneath the hull, the sealing means including means increasing the buoyancy of the gate means to cause the gate means to rise into flrm sealing engagement with the hull, and means for decreasing the buoyancy to cause the gate means to fall away from the hull and permit the gate means to be moved horizontally relative to the hull.

2. The apparatus of claim 1 wherein the gate means includes ballast compartments, said means for increasing the buoyancy of the gate means including means for admitting air into the ballast compartments, and said means for decreasing the buoyancy includes means for flooding the ballast compartments with water.

3. A surface vessel for raising and lowering mining equipment comprising a hull having a bottom, a main deck, and a well opening through the hull from the main deck through the bottom of the hull, gate means movably secured to the bottom of the hull, and means moving the gate means across the bottom of the well opening between an open position and a closed position, means for sealing water out of the well when the gate means is closed, the gate means being constructed with sealed compartments, and further including means for pumping air into the compartments to displace water and increase the buoyancy of the gate means, and means for releasing the air and flooding the compartments with water to reduce the buoyancy of the gate means.

4. Apparatus of claim 1 wherein the gate means include first and second gates, guide means extending fore and aft along the bottom of the vessel along either side of the well, the gates being movable horizontally between said guide means, and drive means for moving each of the gates along the guide means toward or away from each other to close or open the well.

5. Apparatus of claim 4 wherein each of the gates includes sealing strips along the periphery for sealing the gates to the bottom of the hull and sealing the interface between the two gates when they are in the closed position.

6. Apparatus of claim 5 wherein the margins of the gates overlap the bottom of the hull on either side of the well, the sealing strips engaging the bottom of the hull when the gates are closed and pumped with air.

7. Apparatus of claim 6 wherein the guide means permits movement of the gates over a limited distance toward and away from the bottom of the vessel, whereby flooding of the gates causes them to sink away from the hull and inflating the gates causes them to rise,

pressing the seals against the bottom of the vessel.

Claims

1. A vessel comprising a hull, an open well extending vertically through the hull, and gate means for opening and closing the bottom of the well, said means including means for sealing off the bottom of the well when the gate means is closed, said means for opening and closing the well including means slidably supporting the gate means for movement horizontally beneath the hull, the sealing means including means increasing the buoyancy of the gate means to Cause the gate means to rise into firm sealing engagement with the hull, and means for decreasing the buoyancy to cause the gate means to fall away from the hull and permit the gate means to be moved horizontally relative to the hull.

7. Apparatus of claim 6 wherein the guide means permits movement of the gates over a limited distance toward and away from the bottom of the vessel, whereby flooding of the gates causes them to sink away from the hull and inflating the gates causes them to rise, pressing the seals against the bottom of the vessel.