GB1581090A - Floating dock - Google Patents

Description

(54) A FLOATING DOCK (71) We, GOTAVERKEN ARENDAL AB, a Swedish Company of Arendal, Goteborg, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a floating dock.

A floating dock of conventional type comprises a supporting bottom structure having side walls along its longitudinal sides for providing inter alia, the necessary stability, when the dock is lowered. The bottom structure includes a number of displacement tanks, which are filled with water, when the dock is to be sunk, and which must be emptied when the dock is to be raised.

Pumps for handling the ballast water are usually located in lower parts of the side walls, while their driving motors are accommodated higher up in the side walls, in spaces which during most of the working time will remain above water level. The transfer of torque is obtained by means of long, vertical shafts, for which it is difficult to provide satisfactory journalling and lubrication. The outlets from the pumps are directed horizontally outwardly from the dock's sides.

In order to accommodate the lowered dock, a well is often excavated in the sea-bed outside the quay or pier, where the dock is moored, and it is evident, that there is a high risk of such well being filled with mud and debris. The most heavily stressed portion of the dock is located along the centre line of the bottom structure, and it is desirable to locally strengthen this portion.

The object of the present invention is to provide an improved floating dock which takes account of the above mentioned points.

According to the invention there is provided a floating dock of the type comprising a supporting bottom structure having displacement tanks adapted to be emptied when the dock is to be used for lifting a ship, in use, wherein the bottom structure is provided with a bottom plating which is downwardly inclined from opposite longitudinal sides of the structure towards a longitudinal centre line thereof, and a service tunnel extends centrally through the bottom structure and accommodates at least one pump adapted to withdraw water from the displacement tanks, an outlet from said at least one pump being directed downwardly, from said bottom plating of the structure at said centre line.

The service tunnel will strengthen the longitudinal middle portion of the bottom structure, which, together with the bottom plating, which is upwardly inclined from said tunnel, means a good utilization of the strength of the material of the dock. The inclined bottom plating will also mean small volumes of water residue in the displacement tanks and the location of the pumps permits the use of short suction conduits. As the outlet from the or each pump is directed downwardly, an automatic scavenging of the dock well is obtained during each raising operation of the dock.

The invention will now be described by way of example, with reference to the accompanying drawing, the single figure of which shows a portion of a cross-section through a floating dock constructed according to the invention.

The dock includes an elongate, supporting bottom structure 10 and side walls 11, extending along the longitudinal sides thereof. Only one of these side walls is shown in the drawing. Within the bottom structure there is, in a conventional manner, a plurality of displacement tanks. Some of these tanks, 12, are grouped symmetrically to both sides of the centre line CL, of the dock, while other tanks, 13, are located along the outward parts of the bottom structure. These tanks are, in the longitudinal direction of the dock, subdivided into compartments, and these are further subdivided by means of open bulkheads 14. A longitudinal bulkhead 15, within each half of the bottom structure forms a watertight division between the compartments of tanks 12 and 13.

The bottom structure 10 is designed in such a manner, that the bottom plating 16 is inclined downwardly and inwardly, from the opposite longitudinal sides of the dock towards its center line CL.

Due to this form of the bottom plating, tanks 12 will obtain an increased capacity, compared to a conventional dock with a flat bottom, which means an increased lifting capacity in the central part of the bottom structure, where the weight of a ship to be docked mainly will rest. The internally sloping bottom will also mean a reduction of ballast water residues in the empty tanks, and these will also be more easily cleaned.

A service tunnel 17 is provided centrally in the bottom structure, running substantially in its full length. At least one transverse tunnel 18 connects the service tunnel with a watertight staircase 19 within at least one of the side walls 11.

When the dock is in its lowermost position, the level 20 of the water will reach a substantial height along the side walls. When the dock is raised the deck of the bottom structure 10 is located above water level 21, as indicated in the drawing. Access to the tunnels may thus, at any time, be obtained from a passage 22 running along the upper part of the side wall, above water level 20.

In order to facilitate communication with the service tunnel, when the dock is raised, each staircase 19 is provided with a watertight door 23, at deck level.

The service tunnel 17 forms a longitudinal strengthening below central keel-blocks 24.

Some of bulkheads 14 are located so they form supports for sideward keel-blocks 25.

The keel-blocks 24, 25 are situated on the deck of the dock structure.

Pumps 26, driven by electric motors 27 located directly at the pumps, are mounted within the service tunnel 17, and are together with associated valves 30 easily accessible for service and overhaul within the dry compartment provided by the tunnel. Suction pipes 28, 29 connect the pumps with tanks 12 and 13. Due to the central location of the pumps, and by way of suitably fitted valves 30, the total number of pumps may be reduced, and the suction pipes will be comparatively short.

On many occasions a floating dock will be moored along a quay or a pier and it may be desirable to excavate a well 31 in the sea-bed, of sufficient depth to ensure that the deck of the bottom structure will be approximately level with the sea-bed, when the dock is in its lowermost position.

The outlets from the pumps 26 are directed downwardly, and in the embodiment illustrated are also directed outwardly. The forcefull jets of water, caused by pumps locted close by the outlets, will, during each rasing operation, scavenge the well and wash out mud and debris which may have drifted down into the well.

The service tunnel further accommodates supply conduits 32 for electricity, compressed air, steam, fresh and salt water, as well as drain conduits. These conduits may be connected, in use, to a docked ship by way of posts or valves fitted in the deck of the bottom structure. In such manner the number of hoses and cables on the deck is reduced and the companion ways along the side walls remain free.

WHAT WE CLAIM IS: 1. A floating dock of the type comprising a supporting bottom structure having displacement tanks adapted to be emptied when the dock is to be used for lifting a ship, in use, wherein the bottom structure is provided with a bottom plating which is downwardly inclined from opposite longitudinal sides of the structure towards a longitudinal centre line thereof, and a service tunnel extends centrally through the bottom structure and accommodates at least one pump adapted to withdraw water from the displacement tanks, an outlet from said at least one pump being directed downwardly, from said bottom plating of the structure at said centre line.

2. A floating dock as claimed in claim 1, wherein said outlet is directed outwardly.

3. A floating dock as claimed in Claim 1 or Claim 2 wherein the service tunnel, by way of at least one transverse tunnel communicates with watertight staircases arranged within side walls along the longitudinal sides of the bottom structure, and extending above water level when the dock is in its lowermost position, in use.

4. A floating dock as claimed in any one of Claims 1 to 3, wherein longitudinal bulkheads defining the service tunnel and the displacement tanks respectively are located so as to support keel-blocks at the deck of the dock structure.

5. A floating dock substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. the opposite longitudinal sides of the dock towards its center line CL. Due to this form of the bottom plating, tanks 12 will obtain an increased capacity, compared to a conventional dock with a flat bottom, which means an increased lifting capacity in the central part of the bottom structure, where the weight of a ship to be docked mainly will rest. The internally sloping bottom will also mean a reduction of ballast water residues in the empty tanks, and these will also be more easily cleaned. A service tunnel 17 is provided centrally in the bottom structure, running substantially in its full length. At least one transverse tunnel 18 connects the service tunnel with a watertight staircase 19 within at least one of the side walls 11. When the dock is in its lowermost position, the level 20 of the water will reach a substantial height along the side walls. When the dock is raised the deck of the bottom structure 10 is located above water level 21, as indicated in the drawing. Access to the tunnels may thus, at any time, be obtained from a passage 22 running along the upper part of the side wall, above water level 20. In order to facilitate communication with the service tunnel, when the dock is raised, each staircase 19 is provided with a watertight door 23, at deck level. The service tunnel 17 forms a longitudinal strengthening below central keel-blocks 24. Some of bulkheads 14 are located so they form supports for sideward keel-blocks 25. The keel-blocks 24, 25 are situated on the deck of the dock structure. Pumps 26, driven by electric motors 27 located directly at the pumps, are mounted within the service tunnel 17, and are together with associated valves 30 easily accessible for service and overhaul within the dry compartment provided by the tunnel. Suction pipes 28, 29 connect the pumps with tanks 12 and 13. Due to the central location of the pumps, and by way of suitably fitted valves 30, the total number of pumps may be reduced, and the suction pipes will be comparatively short. On many occasions a floating dock will be moored along a quay or a pier and it may be desirable to excavate a well 31 in the sea-bed, of sufficient depth to ensure that the deck of the bottom structure will be approximately level with the sea-bed, when the dock is in its lowermost position. The outlets from the pumps 26 are directed downwardly, and in the embodiment illustrated are also directed outwardly. The forcefull jets of water, caused by pumps locted close by the outlets, will, during each rasing operation, scavenge the well and wash out mud and debris which may have drifted down into the well. The service tunnel further accommodates supply conduits 32 for electricity, compressed air, steam, fresh and salt water, as well as drain conduits. These conduits may be connected, in use, to a docked ship by way of posts or valves fitted in the deck of the bottom structure. In such manner the number of hoses and cables on the deck is reduced and the companion ways along the side walls remain free. WHAT WE CLAIM IS:

1. A floating dock of the type comprising a supporting bottom structure having displacement tanks adapted to be emptied when the dock is to be used for lifting a ship, in use, wherein the bottom structure is provided with a bottom plating which is downwardly inclined from opposite longitudinal sides of the structure towards a longitudinal centre line thereof, and a service tunnel extends centrally through the bottom structure and accommodates at least one pump adapted to withdraw water from the displacement tanks, an outlet from said at least one pump being directed downwardly, from said bottom plating of the structure at said centre line.

2. A floating dock as claimed in claim 1, wherein said outlet is directed outwardly.

3. A floating dock as claimed in Claim 1 or Claim 2 wherein the service tunnel, by way of at least one transverse tunnel communicates with watertight staircases arranged within side walls along the longitudinal sides of the bottom structure, and extending above water level when the dock is in its lowermost position, in use.

4. A floating dock as claimed in any one of Claims 1 to 3, wherein longitudinal bulkheads defining the service tunnel and the displacement tanks respectively are located so as to support keel-blocks at the deck of the dock structure.

5. A floating dock substantially as hereinbefore described with reference to and as shown in the accompanying drawings.