GB2037351A

GB2037351A - Harbour Installations

Info

Publication number: GB2037351A
Application number: GB7848698A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-12-15
Filing date: 1978-12-15
Publication date: 1980-07-09
Also published as: AU5384979A; GB2037351B

Abstract

At a berth 112 for roll-on roll-off unloading and loading of a ship 116, vehicle bridges 118, 120, 122, 128 are provided to give access both through either a bow or stern door and one or more side doors or at least two side doors (of the ship). In this way, a through-flow of traffic can be established, instead of all traffic in and out having to pass through a single door. <IMAGE>

Description

SPECIFICATION Harbour Installations This invention relates to harbour installations which include, for the roll-on roll-off loading and unloading of ships, ship to shore vehicular bridges of the kind affording a vehicular track, the beam being supported at its shore end by a pivotal connection which has a capability of permitting the beam to hinge around at least a substantially horizontal axis, t6 enable the ship end of the beam to rise or fall. Such a bridge will be referred to hereafter as a ship to shore bridge of the type specified.

One example of this type of bridge is known as a linkspan, a part of the load of the bridging beam and traffic thereon being taken adjacent the ship end by means of a buoyancy tank or tanks secured to the underside of the bridging beam. In some cases, the buoyancy of this tank or tanks is capable of adjustment by varying the volume of air therein, for example by means of a compressor and a venting valve. In a particularly convenient form of this type of abridge, the buoyancy tank or tanks are connected to the bridging beam by a tank leg or legs which are of fairly slender crosssection, in comparison with the plan area of the tank or tanks. With such an arrangement, a small adjustment of the buoyancy of the tank or tanks will be sufficient to shift the ship end of the bridging beam vertically to match the freeboard of a ship preparing to berth.Also, it is possible to link the ship end of the bridging beam to the ship, so that the end of the beam rises and falls with changes in the freeboard of the ship; although this will produce some change in the displacement of the buoyancy-providing structure of the bridge, the slenderness of the tank legs will mean that this change in displacement, and the corresponding change in buoyancy, will be minimal. The ship end of the bridge can therefore be partially borne by, for example, being hooked on to the ship, or by being suspended from the ship by means of one or more cables, without introducing the possibility of a large increase in the load on the hook or cables if the freeboard of the ship should increase, or if the relative vertical positions of the ship and the buoyancy tank should try to change owing to wave action.

An incidental advantage of such an arrangement of buoyancy tanks and tank legs is that the buoyancy-producing structure, being almost entirely immersed, is little affected by wave action.

Such ship to shore bridges are well known and are commonly used in association with roll-on roll-off ferries, for example, having stern doors with the interposition of either one or more stern ramps carried by the ship or a number of retractable flaps carried by the bridging beam itself.

Such bridges are capable of limited adjustment either by translational movement along the pivotal connection or by a slewing through a relatively small angle at the pivotal connection; in the application mentioned above, in which the bridge is used for loading and unloading through a stern door, this adjustment allows the bridge to be used with ships of varying beam, and varying stern door position.

According to one aspect of the present invention, a harbour installation for the roll-on roll-off loading-unloading of a ship comprises a berth for the ship and at least two ship to shore vehicular bridges of the type specified of which one bridge is positioned for loading-unloading of the ship through a bow or stern door and the other is positioned for loading-unloading through a side door. By this means, it may be possible for one bridge to be used for traffic onto the ship and for another bridge to be used for traffic off the ship. In one particular embodiment, two, three or more ship to shore vehicular bridges of the type specified may be positioned at spaced intervals for loading-unloading of the ship through a plurality of similarly spaced side doors.

Arrangements of this kind may be particularly appropriate where the face of the shore is of a gradually sloping nature. Such a face has the advantage that it is much cheaper and easier to construct than a vertical-faced quay. In this case, the ship may be berthed offshore, for example, against a number of dolphins or the like, and those ship to shore vehicular bridges which are positioned to load and unload the ship through side doors may extend between pairs of dolphins.

In a modified aspect of the present invention, the ship to shore bridge for loading-unloading through a bow or stern door is dispensed with, and loading-unloading facilities are provided entirely by a plurality of ship to shore vehicular bridges of the type specified, each positioned for loading-unloading through a side door of the ship.

The invention may be carried into practice in a number of ways but one specific embodiment will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a plan view of a known ship to shore vehicular bridge; Figure 2 is a side elevation of the bridge of Figure 1 shown connecting the shore to a ship; Figure 3 is an end elevation of the bridge of Figure 1 and 2 as viewed from the ship end; Figure 4 shows an alternative method of connection of a bridge to a ship in which the ship end of the bridge is booked onto the ship in a case where a very wide ship's ramp is employed; Figure 5 is a plan view of the arrangement of Figure 4; Figure 6 shows an alternative method of connecting the ship end of a bridge to a ship in the case where a double ship's ramp is employed; Figure 7 is a plan view of the arrangement of Figure 6;; Figure 8 shows a further arrangement where the ship end of the bridge is supported by a pair of cables from a ship with no stern ramp; Figure 9 is a plan view of the arrangement of Figure 8; Figure 10 diagramatically illustrates the range of positions which the bridge can occupy by either translational movement of the shore end of the bridge and/or slewing at that end; Figure 11 is a plan view of a harbour arrangement embodying the present invention; Figure 12 is a vertical section taken on the line XIl-XilofFigure 11; Figure 13 shows the ship end of a modified form of ship to shore bridge, in side elevation; and Figure 14 is an end elevation of the construction of Figure 13.

In order that the embodiment of the invention can be fully understood, a description will first be provided of a conventional bridge by way of reference to Figures 1 to 10. Thus, Figure 1 shows a vehicular bridge generally indicated at 10 which is constructed as an elongated box-like structure having a main upper deck 11 over which traffic can pass between a shore end of the bridge shown at the right hand side in Figures 1 and 2 to the ship end shown at the left hand side in Figures 1 and 2. In Figure 2, the bridge is shown bridging a gap between a shore 12 and a ship 14. In addition to the deck 11 for vehicles, a pedestrian track 1 6 is provided along one edge of the bridge.

At its shore end, the bridge rests on a tubular support 18, rigidly mounted in a structure 20, built into the shore 12. As is conventional, the shore end 22 of the bridge 10 merely rests on the tubular support 18 which in effect provides a fulcrum for rotational movement of the bridge 10 about a horizontal axis to accommodate changes in tide and freeboard of ship.

A downwardly-projecting bracket 21 on the underside of the bridge 10 prevents the bridge from moving away fron the shore off the support 18; a rubber buffer 1 3 is fitted to the left-hand face (as seen in Figure 2) of the bracket 21, and abuts against the support 1 8 if the bridge should tend to make such a movement. A further rubber buffer 23 is mounted on the end face of the shore end of the bridge 10; if the bridge should be subjected to an endways impact by a ship as the ship berths, the buffer 23 will abut against the fixed structure 20 to bear this load, without stressing the tubular support 1 8. Brackets (not shown) are also provided to prevent the shore end of the bridge 10 from lifting away from the support 18 if such an impact should occur.The shore end of the track 11 of the bridge is connected to a roadway 26 on the shore by means of hinged flaps 28 and 30. The ship end 32 of the bridge is supported by a buoyancy tank 34 connected to the bridge by a pair of buoyant legs 36. When no ship is berthed at the ship end of the bridge, the buoyancy tank 34, together with the buoyant legs 36, provides the only support for the ship end of the bridge. The tank 34 is made of such a size that, when completely empty of water, its buoyancy is more than sufficient to support the ship end of the bridge. Internally, the buoyancy tank 34 is divided into watertight compartments, and to allow the buoyancy of the tank to be adjusted, and thereby raise or lower the ship end of the bridge, one of these compartments is openbottomed, so that it can be controllablyflooded.

Means is provided, but not shown, for admitting air under pressure to the open-bottomed compartment, to expel water from the compartment and thereby raise the ship end of the bridge, and for releasing air from the compartment, to allow the compartment to become more flooded and thereby lower the ship end of the bridge.

In this way, the bridge can be adjusted to match the freeboard of a ship which is about to berth. Normally, the buoyancy tank 34 is completely immersed, so that only the small cross-section of the buoyant legs 36 breaks the surface. This means that the height of the ship' end of the bridge can be adjusted by only a small change in the buoyancy of the tank 34, but it also means that the bridge would sink considerably as soon as any appreciable load were applied to it, if no other means of support were provided.

When the bridge is actually in use for loading or unloading a ship, both the weight of the bridge and the weight of any traffic on it has to be supported. The buoyancy tank 34 and the buoyant legs 36 continue to support a part of this combined load, while the remainder of the loads borne at the ship end by the ship itself by means of a pair of cables or chains or other flexible elements 40 which are connected to the ship end 32 of the bridge by means of gimbal mounted support cylinders 42 arranged automatically to take up or let out lengths of cable or chain in order to support the bridge equally on both edges irrespective of roll or list of the ship.After the cables or chains 40 have been connected during berthing operations, the buoyancy of the tank 36 is reduced slightly, to ensure that the cables 40 do not become slack, even when there is no traffic on the bridge.

As can be seen from Figures 1 and 2, the ship has a stern ramp 43 which is lowered on to the deck of the bridge to allow vehicular access into the ship. The ramp 43 is sufficiently narrow that it does not obstruct the cables or chains 40. There are a number of alternative ways of connecting the deck of the bridge to the ship itself and these will be discussed in relation to Figures 4 to 10.

In Figures 4 and 5 a bracket 50 is provided at the stern of the ship which is engaged by a hook 52 on the ship end of the bridge 1 0. In this case, the ship is provided with a very wide ramp 54 which is wider than the ship end of the bridge 10, so precluding the possibility of utilising the cables or other suspension-type supports from the ship.

Such a bracket and hook arrangement could, of course, be used with the narrower ramp of Figures 1 and 2.

Figures 6 and 7 illustrate an arrangement in which the ship has a double ramp 56 permitting a single or double cable 58 to pass between the ramps to engage a hook 60 on the end of the bridge.

Figures 8 and 9 illustrate a ship which has no ramp. The gap between the end of the bridge deck and the ship is in this case bridged by a series of retractable flaps 44 carried by the bridge.

When the flaps 44 are not required, as when handling a ship which has a ramp, they can be retracted beneath the end portion of the roadway formed on top of the bridge. With such an arrangement, the bridge can be used to handle ships both with and without ramps.

Figure 10 diagramatically illustrates the manner in which the ship end 22 of a bridge can be translationally moved from a mean position to either of two extreme positions simply by sliding the shore end 22 of the bridge along the tube 1 8.

Suitable tackle or mechanised methods for this purpose may be incorporated but are not shown.

In any translated position, the bridge can then be slewed through a relatively small angle, as shown, in order to align the ship end 32 of the bridge with the loading gate or loading ramp of the ship regardless of the width of the ship.

Figure 1 also indicates at 70 a position of the ship end 32 in its maximum translated and slewed position to one side.

Figure 11 illustrates, in plan view, two portions 110 and 112 of a shoreline lying at right angles to one another. As can be seen from Figure 12, the shoreline is formed with a sloping or battered face, formed simply by tipping material. The natural angle of repose of the material determines the angle of the battered face. Spaced from the shoreline, in deep water, are a series of dolphins 114 against which a ship 11 6 is moored. Along the portion 112 of the shoreline three spaced bridges 118, 120, and 122 are provided which may be of conventional form, for example, as described in connection with Figures 1 to 10. It will be seen that the spacing between the bridges 118, 120 and 122 is such that one bridge extends between each pair of dolphins 114.As described previously, with conventional bridges of the type shown in Figures 1 to 10, each of the bridges 118, 120 and 122 can be moved slightly translationally along its shore end mounting and/or be slewed through a small angle in order to align the ship end of each bridge with the appropriate side door of the ship 11 6. The ship end of each of the bridges is connected to the two adjacent dolphins 114 by a pair of cables 11 9.

One end of each cable is fixedly anchored to the dolphin, while the other end is wound on to one of a pair of winches (not shown) mounted at the ship end of the bridge. Thus, by operating the winches, the ship end of each of the bridges can be moved laterally to align it with the appropriate side door of the ship 116.

In addition, a single bridge 128 extends from the portion 110 of the shoreline for roll-on roll-off connection to a stern (or bow) door of the ship 116.

Since it is not normal for the side doors of a ship to be provided with loading-unloading ramps, the bridges 118, 120 and 122 are provided at their ship ends with retractable flaps 124, to bridge the gap between the end of the bridging beam and the ship, in the manner illustrated in Figures 8 and 9. No such flaps are provided on the bridge 128, since ships which are arranged for loading or unloading through the stern normally have a stern ramp which will provide vehicular access into the ship. However, it is possible to provide retractable flaps on the bridge 128 also, and this will.increase the variety of types of ship which can be handled by the berth.

If the amount of translation of the shore end of the bridges 11 8, 120 and 122 which can bye achieved by shifting the bridges along their shore end mountings is inadequate to allow sufficient adjustment of their ship ends, the arrangement shown in Figures 13 and 14 can be used to support the shore end of each of these bridges. In this arrangement, the shore end of the bridge is mounted on a tubular support 222 carried by a bogie 224 having wheels 226 which are carried on quayside rails 228. Thus, the whole bridge, together with the bogie 224, can be shifted translationally by moving the bogie along the rails 228. In any one position, the bridge is retained in position in the manner shown in Figures 13 and 14 by means of a pair of ties 130.

When the bridge takes compression loads on berthing these are absorbed by the buffer 240, without being transmitted to the bogie 224. Any tension loads in the bridge which are transmitted to the bogie cannot lift the bogie, since the bogie has members 242 underhanging the rails 228.

Whichever arrangement is adopted for mounting the shore end of the bridges, it is necessary that the bridges should be able to withstand impacts from the ship as it berths. This is partly because the dolphins 114 are somewhat flexible, so that, even if the ends of the bridges 11 8, 120 and 122 are somewhat set back from the line of the front faces of the dolphins, so that the ship comes into contact with the dolphins first, it cannot be guaranteed that the ship will not then come into contact with the bridges as the dolphins deflect.The amount by which the ends of the bridges are set back from the front faces of the dolphins will be at a maximum when the bridges are in their most inclined position, so that, even if the bridges are so arranged that this setback corresponds to the greatest allowable gap between the ends of the bridges and the ship, the set-back will be considerably reduced or even eliminated when the bridges adopt a horizontal position.

As has already been described, the type of ship to shore bridge shown in Figures 1 to 3 is capable of withstanding berthing shocks, and is therefore suitable for use in the harbour arrangement of Figures 11 and 12.

This arrangement of bridges provides for extremely fast loading and unloading of a ship, for example, a container ship. In contrast to a ship which only has a stern door, so that all the cargo has to be loaded or unloaded through the stern of the ship, the arrangement shown in Figure 11 is extremely flexible. For example, each of the bridges 118, 120, 122, and 128 may be individually used for roll-on, roll-off purposes or alternatively, a traffic flow through the ship itself may be developed, for example, by traffic rolling on the ship via the stern bridge 128, and off the ship via any of the bridges 118, 120, or 122. It is believed that systems of the type shown in Figure 11 will very drastically improve the turn round time of a ship and so have very considerable economic advantages.

The arrangement of the bridges 11 8, 120 and 122 also provides access to the ship which is virtually as good as that obtained when the ship is berthed alongside in a dock, but without the expense of contructing a vertical quay face.

Claims

1. A harbour installation for the roll-on roll-off loading-unloading of a ship comprising a berth for the ship and at least two ship to shore vehicular bridges of the type specified of which one bridge is positioned for loading-unloading through a bow or stern door of a ship in the berth and the other is positioned for loading-unloading through a side door of the ship.

2. An installation as claimed in Claim 1 in which the said other bridge is one of a plurality of similar ship to shore vehicular bridges of the type specified positioned at spaced intervals for loading-unloading of the ship through a plurality of similarly spaced side doors of the ship.

3. An installation as claimed in Claim 1 or Claim 2 in which the berth is an offshore berth provided by a number of dolphins or the like, with the or each bridge which is positioned for loading and unloading the ship through a side door of the ship extending between a pair of dolphins.

4. A harbour installation for the roll-on roll-off loading-unloading of a ship comprising a berth for the ship and at least two ship to shore vehicular bridges of the type specified, each bridge being positioned for loading-unloading through a side door of a ship in the berth.

5. An installation as claimed in any of the preceding claims, in which each of the ship to shore bridges includes buoyant means supporting its ship end.

6. An installation as claimed in any of the preceding claims, in which each of the ship to shore bridges is capable of absorbing berthing shocks directed longitudinally of the respective bridge.

7. An installation as claimed in any of the preceding claims in which at least one of the bridges for providing vehicular access to and from a side door of the ship in the berth is supported at its shore end by a travelling support carriage which is capable of movement parallel to the length of the berth, to allow the bridges to be aligned with side doors of the ship.

8. A harbour installation substantially as described herein with reference to Figures 11 to 14 of the accompanying drawings.