WO2023031573A1

WO2023031573A1 - Container lashing device for ship's decking

Info

Publication number: WO2023031573A1
Application number: PCT/GB2022/000071
Authority: WO
Inventors: Martin Clive-Smith
Original assignee: Clive Smith Associates Ltd
Current assignee: Clive Smith Associates Ltd
Priority date: 2021-09-06
Filing date: 2022-08-24
Publication date: 2023-03-09
Anticipated expiration: 2024-03-06
Also published as: GB202112674D0

Abstract

A container lashing device for securing columns of containers on the deck of a container ship against transverse sway. The device comprising a support means secured to the deck and carrying restraining means engageable with a container in a column of containers to restrain transverse sway of the column in at least one direction, the restraining means being moveable to disengage the container to allow unloading of the column of containers whilst still being supported from the support means. The support means may comprise a frame whose base is supported from the deck and which carries one or more restraining means in the form of a projection which overlaps and extends alongside part of a side of a container in the column to be restrained. Alternatively, the support means may comprise a longitudinally telescopic boom, a lower end of the boom being supported from the deck and an upper end of the boom carrying the restraining means.

Description

Container Lashing Device for Ship's Decking

This invention relates to stabilizing one or more stacks of containers stacked one on another on the deck of a sea going container ship to stop them toppling overboard when sailing in high seas during heavy storms. Containers empty or laden can be stacked 10 or even 11 high on the deck of a container ship and are typically just under 2.5m wide and just under 3m high so that a 10 high stack of them is 30m tall yet 2.5m wide. These stacks are thus inherently unstable. The containers within a single stack are locked to each other with twistlocks one at each corner of the container where there is a vertical corner post capped top and bottom with a known corner fitting which has apertures formed in it to engage with a twistlock. At the bottom of the stack the bottom container is locked to the deck of the ship by another 4 twistlocks. There are working clearances between the twistlocks and corner fitting apertures so that as the ship sails on rough seas and the ship begins to roll one way and then the other, the stack naturally starts to sway side to side. The taller the stack the more the sway. The containers themselves also have natural structural flexibility so that the limit of each sway is ultimately governed by the accumulation of all clearances in the twistlocks and deflection of the container up to the elastic limit of its structure. Each sway puts the twistlocks and the corner posts of the containers on one side of the stack into compression, and ultimately on the other side into tension. In the most extreme conditions, the twistlocks can break in tension, or the twistlocks can pull out of the corner apertures or the elastic limit of the container is exceeded or a corner post buckles or breaks and this failure results in lost containers and cargo overboard.

Figs. 1 and 2 show diagrammatically a prior art arrangement for stabilizing side to side sway of containers in which a container ship 10 has a deck 11 on which containers 12 are stacked in a number of individual stacks 13 each made up of five columns 14 of containers. Each container is locked to the one below by twistlocks 15 (see Fig.5) engaging with the hollow steel boxes which are the container corner fittings 16 on the eight corners of each container 12. The deck 11 of the container ship has hatches 65 provided with hatch covers 17 which can be lifted off by a crane spreader 18 to give access to the ship's hatches below the deck where additional containers 12a are transported. The hatch covers are made of necessity wider than the length of the containers which are stacked on and locked to the hatch covers by twistlocks 15 engaging the corner fittings 16 in the bottom container 12 of each column 14. To add to the security of the stacks and enable stack heights to be taller than about four high above deck, large steel space frames called lashing bridges 19 are provided fixed transversely to the deck 11 between the removable hatch covers 17 on which the containers 12 are stacked. The through space "A" (see Fig 1) between the lashing bridges is called a container bay 20 and when moving the containers or covers on and off ship the width denoted space 'A' must be made clear of projections from the lashing bridges. The container columns 14 are lashed to the lashing bridges by lashing bars 21. The bottom end of each lashing bar is hooked to the bridge at a lashing point and the top end of each bar engages one of the apertures in a corner fitting 16 of a container 12 in a column 14 to be stabilized.

Although Figs. 1 and 2 only show the lashing bars used on one side of the stacks of containers it will be appreciated that, if container loading and weather conditions require, lasing bars can be deployed on both sides of the stacks 13 so that both ends of the container columns are restrained.

As will be appreciated, these lashing bars are unwieldy and difficult to use by stevedores who must climb up long ladders, steps and along narrow walkways along the top of the lashing bridges 19. Typically, the lashing bars are about 5m long and weigh about 25 kg. and a large container ship of 24,000 teu capacity might have 18 lashing bars per column of containers with 24 columns per bay and 24 bays thus needing 10,000 lashing bars which all have to be fitted manually and removed before unloading is possible. The bars include turnbuckles so that a pre-tension restraint can be achieved on the container to be stabilised even before any sway might take place. Those containers stacked above the height that the bars can reach are still only stabilised by their twistlocks.

Thus it will be seen that this prior art arrangement is time consuming to install and remove, weighty and only effective for a few rows of containers above the lashing bridge.

It is an object of the present invention to provide a container lashing device which mitigates the above problems.

Thus according to the present invention there is provided a container lashing device for securing columns of containers on the deck of a container ship against transverse sway, the device comprising a support means secured to the deck and carrying restraining means engageable with a container in a column of containers to restrain transverse sway of the column in at least one direction, the restraining means being moveable to disengage the container to allow unloading of the column of containers whilst still being supported from the support means.

Other features of the invention are set out in the accompanying claims 2 to 35.

The present invention will now be described, by way of example only, with reference to the accompanying drawings in which

Figs 1 shows a perspective view of a prior art lashing arrangement connected between columns of containers and a lashing bridge which extends transversely across a deck of a container ship;

Fig. 2 shows an end elevation view in the direction of arrow X of Fig. 1;

Figs. 3 shows an end elevation, and 4 and 5 show side a perspective views of a first form of lashing system accordance with the present invention which uses a telescopic boom;

Figs. 6 shows diagrammatically the sway forces imposed on a column of containers which are unrestrained other than by their twistlock connection to themselves and the ships deck;

Fig. 7 shows diagrammatically the sway forces imposed on a column of containers which are restrained by the first form of lashing system shown in Figs. 3 to 5, and also the restraints from figure 10;

Fig.8 shows a second form of lashing system in accordance with the present invention;

Fig. 9 shows a third second form of lashing system in accordance with the present invention;

Fig. 10 shows a fourth form of lashing system in accordance with the present invention;

Figs. 11, 12 and 13 show a fifth form of lashing system in accordance with the present invention;

Fig. 14 shows a crane spreader lifting a container of a column of containers with lower containers still lashed in position;

Fig. 15 shows an actuator arrangement for pivoting the boom of Figs. 4 and 5 about a vertical axis, and Fig. 16 shows a further form of the present invention which uses linearly displaceable restraining means.

Referring to Figs. 3 to 5 these show a support means in the form of longitudinally telescopic boom 24 which is of a bulkier construction than the previously described lashing bars 21 and which carries at its upper end a restraining means in the form of a connector 25 for engaging an aperture 26 in a corner fitting 16 of one of the containers 12 in a column to be restrained against transverse sway. The lower end of boom 24 is supported from the deck 11 via lashing bridge 19 on a base support 27 on which is mounted a turntable 28 able to rotate about vertical axis 29 and on which the boom mounted for pivoting about a horizontal axis 30 relative to base support 27. The base support is mounted on lashing bridge 19 through the existing mountings for the previously described lashing bars 21 or via purpose built fixings. A boom elevation actuator 31 of any suitable form powered electrically or hydraulically or a combination of both acts between the boom 24 and the base support 27 to adjust the height of the boom 24 in an arc about axis 30. The boom 24 is formed in two sections 24a and 24b which can be moved telescopically relative to each other by a telescoping means in the form of a second actuator 32 to change the effective length of the boom The actuator 32 can again be of any suitable form powered electrically or hydraulically or both and may employ rack and pinions, pullies, winches, rams, and/or screws. A further boom swing actuator 66 (see Fig.15) acts between the base support and the turntable to swing the turn table carrying the boom about axis vertical axis 29. In this way the location of the connector 25 seen in Fig. 5 can be aligned with an aperture 26 of a corner fitting 16 of a chosen container 12 using actuators 31, 32 and 66.

Since boom 24 is more massive than the previously described lashing bars 21 it can potentially now take compression loads as the ship rolls to the left.

No lashing bars are shown. The system envisaged in this invention can be devised to not require any lashing bars, or can be mixed and matched to include one or more of the examples of the present invention and lashing bars and lashing bridges to suit the many variables of cargo and marine environment and provide solutions for the ship designer to accommodate these variables. In Fig. 4 three stacks 13 of containers 12 with five columns 14 in each stack are shown. Between the stacks 13 there is a gap B representing the gap between the hatch covers 17 below and out of this view. It is envisaged that additional telescopic booms 24 could be deployed to capture the sway of all stacks across the width of the ship 10 as shown on the left of Fig. 4. Fig. 4 also shows one of the booms 24 not yet deployed on its allotted stack.

In Fig. 5 the upper end of the boom 24 is shown in more detail. Connector 25 is illustrated in the form of a small twistlock 33 of geometry matched to the aperture 26. With the twistlock positioned in alignment with aperture 26, the turntable 28 can be rotated about vertical axis 29 by a suitable boom swing actuator 66 (see Fig. 15) and the twistlock 33 inserted through aperture 26 and once inside the corner fitting 26 rotated via a rotating lever 34 and a further actuator 35 to twist and lock into the corner fitting 16.

The location of the boom 24 requires power. Electrical power is envisaged to be supplied by the ship's own system or via auxiliary supplies. The control of the actuators moving the boom 24, turntable 28, beams sections 24a, 24b, connectors 25 is via a remote wireless control handled by the stevedore 22 or on a cord held by the stevedore. It is envisaged that the connector can be located automatically within the target of the aperture 26 by computation given that the position of stack 13 and the height of the container selected are all known and the geometry such as the heights, widths and other dimensions of the corner fittings are all standardised. Finer adjustment can be achieved if required by the inclusion of a video camera (not shown) mounted on the boom near the connector transmitting a closeup view of the connector 25 and aperture 26 to the stevedore, or further automated by the provision of known proximity sensors mounted on the connector to indicate its location.

When the containers or covers 40 are to be loaded or unloaded from the ship, the boom 24 must be moved away from the space 'A' through the bay 20 and this can be done automatically by programming of the control system of the boom 24 to perform rotation about axis 29 indicated by arrow F, telescoping inwards or outwards movement of boom sections 24a, 24b as indicated by arrow G, and rotation about axis 30.

Adjustment of the boom 24 can be made for length, pre-load, and for both tension and compression and can be set at different levels or strength. For cushioning swaying forces hydraulics or friction brakes and/or relief valves in the actuators are provided. If the telescoping actuator such as actuator 32 requires fixing at a given length, then additional pins of known design can be fitted to lock the boom sections 24a, 24b to each other in a given position. Free play in twistlocks, gaps between containers, and deflections in the structures can be equalled by providing clearances in the linkage of the actuators. So if the limits of sway deflection due to free play was found to be for example 100mm measured at the location of the connector 25, and the maximum safe elastic deflection of the combined structure was 200mm, yet on the high seas the stacks 13 were likely to encounter forces to drive them over the limit beyond a total 200mm, then in one example the boom 24 could be set up to have some free play or cushioned movement to allow the connector to move 100mm or slow up the sway deflection and then allow the boom 24 to withstand further deflection of say 200mm with enough strength and rigidity combined with that offered by the stack to prevent the sway deflection exceeding 200mm. Likewise a sway deflection might be set for the frame in compression to suit. In this way, the capability of the lashing system plus the frame 24 can be optimised without one doing more unnecessary work than the other.

In service, as the stack 13 begins to sway, the container 12' moves relative to the boom 24 and its connector 25 such that collar 36 of the twistlock comes into abutment with the internal surface 37 at one side of the aperture 26. As the sway inevitably moves in the opposite direction, the collar 36 then abuts the other side of the aperture 26 on surface 37 restraining the container 12' and the stack 13 of which it is a part in both directions.

The upper end of each boom 24 can carry an additional ram 38 which can be extended to contact the corner fitting 16 or a container below to push the boom away to withdraw the connector from the container if jamming of the twistlock 33 or collar 36 were to occur. The nearest and thus preferable connection point of a container 12 is its bottom corner fitting 16 and the corner fitting 16' of the container 12'' below is located directly vertically below it connected via the twistlock 15. Corner fittings are made of a steel which is attractive to magnets. Thus if the ram 38 were fitted with a known magnetic switchable device or electro releasable magnet 39 the ram 38 with the magnet energised would be attracted towards the corner fitting 16 and thus draw the connector 25 towards the corner fitting 16 and help engage the collar 36 of the connector with the aperture of the corner fitting 16'. In fig. 4 where the boom 24 is required only to take tensile loads, then the size, strength and weight of the boom might be reduced whilst retaining a telescopic capability and cushioning. In this event it is envisaged that one section 24a of the boom might be made as a circular section tube of some 60mm diameter telescoped to a boom section 24b of tube 80mm diameter with a manual pin and cooperating hole system to lock them together. The raising and lowering, extending and rotating could all be done manually or using known mechanical gear boxes, actuator screws, or jacking devices utilising manual power or that of a battery powered drill. Connector 25 in lieu of a twistlock 33 as in figure 5 could be envisaged to be made as a hook and a cam fixed to boom 24 to engage with aperture 37 and as it is rotated about the longitudinal axis of the boom sections 24a, 24b. As indicated earlier, Fig. 15 shows a plan view in section of the corner 15 or a container 12 with boom 24 and connector 25 approaching it for connection. The turntable 28 is seen mounted on base 27 with vertical axis 29. Rotation about the axis 29 is provided by actuator 66 pinned between base 27 and turntable 28 and the arc arrows indicating the movement inwards of the boom towards the container. As the boom 24 is rotated to position 24' the connector 25 can enter the aperture 3 in the corner fitting 15 and the twistlock action of the connector employed to lock it in place.

Although a twistlock 33 is illustrated, it is envisaged that a plain shaft of suitable section without a rotating head and no collar 36 could be used.

Figure 6 shows an end elevation with a column 14 of containers stabilised according to the prior art arrangement shown in Figures 1 and 2 as seen on deck 11 or lashing bridge 19. In this arrangement the containers are shown having a height "h" and a width "w" and the lashing bars are omitted and the containers are simply locked together with known twistlocks 15 including twistlock 39 at the bottom lefthand corner. As the ship rolls, the column 14 sways to the right and then as the roll reverse to the left the inertia of the column and the acceleration 'a' acting on them as the ship tries to up right itself by rolling to the left causes a moment about corner D. The column 14 sways as indicated by dotted line 14' to the right of the deck putting twistlock 39 in great tension. The moment of column 14 is balanced by a counter clockwise moment of the twistlock force V acting about corner D a distance width w from D. In Figure 7 there is shown a similar diagram of the sway of an arrangement of the present invention as shown in Fig. 5 illustrating two types of restraint.

Firstly, there is a column 14 of containers, the same as column 14 of Fig. 6 sways as indicated by dotted line 14". Column 14 is restrained by boom 24 and connector 25 of Fig. 4 and 5 which is connected to a lower corner 62 of the top container in column 14. The line of action of force T3 is that generated within boom 24 with connector 25 acting high up the column at a point 62a some 5 container heights above the corner D so that the force T3 in the boom 24 acts a moment arm distance E from the bottom corner D some 4 times larger than width 'w' and potentially acting in unison with the capability of force V2 in the twistlock 39. In practice the optimum position of the connector would be determined by theory and practice and might for example be located at location 62b.

Rudimentary calculations show that where a boom 24 and connector 25 are attached to the underside of the top container in a column 14 with the boom being set at a 45 degree slope to the horizontal and with the boom 24 being connected well away from the corner D, the boom 24 can, without making it substantially stronger than a known lashing bar 21, but longer, could support 5 times more securing load.

Present day computerised calculations with inputs of container weights, fasteners, ships design and size, heights of stacks, weather patterns and several other variables are used to advise the ships master how to optimise the location and weights of the containers. Each ship and its cargo and equipment is different to the next so each ship using the lashing system of present will need to go through the same process and analysis for each type of system used.

In extreme service as the columns of containers begin to sway substantially each stack column can lean on the adjacent column and adjacent stacks of columns also lean on each other as indicated by a column 14"' shown in dotted line leaning on column 14 making contact at the top and stopped from sideways movement at the bottom container at its connection to the deck so that gap C remains.

Secondly, in Fig. 7 the connector 25 and boom 24 are absent and the restraint is provided by projections 70, 70' located near the top and near the middle of a column of containers (as shown in Fig. 10). An adjacent column of containers 14'" shown in dotted line is seen to lean on column 14 making contact at least at the top and bridging the gap C between two adjacent columns of containers in a stack typically 25mm when at rest at the quayside on a horizontal deck of a ship. It can be seen that the projection 70' stands away from the side of the column to allow greater natural deflection of the column and enable the column to develop the natural biase against sway that its structure can provide before needing the restraint provided by projection 70'. By combining the resilience of the column 14 and the matched projections 70,70' several more columns 14"' and others not shown can be supported against being overstressed.

In addition, the lower restraining means 70 can be deployed to restrain lower containers in a column whilst the restraining means 70' of the upper containers in the column can be deactivated to allow loading and unloading of these upper containers. The forces acting on the column 14 directly in contact with the projection 70 is similar to horizontal force H3 illustrated in figure 7 and a moment arm E greater still.

There are various ways envisaged to form the support means, even combined, for example, in Fig. 8 a lashing bridge 50 carries support means in the form of triangular frames 51 with column 83 and stays 71 whose bases are supported from the ship's deck via the lashing bridge.

Restraining means such as projections 70 as seen in figure 10 can be fixed to the column 83. The frames 51 are permanently or removably secured to the lashing bridge 50. In the arrangement shown four stacks 53 of columns 14 of containers 12 are seen stacked on hatch covers 17 having gaps B between them as before in the previous arrangements described.

Alternatively, if connectors 52 of Fig. 8 were to be similar to connectors 25 previously described, it is envisaged that a very short boom, say only 1 to 2m long could be mounted via its base 27 directly onto the frame 51, with actuation and connection as described earlier and able to act with the boom 24 orientated for movement in a substantially horizontal plane to insert the connectors 52 into the required corner fitting apertures.

In Fig. 9 the support means comprises a lashing frame 60 which is similar in appearance to lashing bridge 50 but is taller and lighter weight. This lashing frame carries restraining means as described around the example of figure 8. The height of the frame 60 is determined largely by the number of containers that can be stacked at the top of a stack without need of lashing bars although that remains an option. For empty containers twistlocks alone may be sufficient for stacking two or three high above the uppermost restraint means.

When lashing bars are not needed, walkways for stevedores can be omitted and the space gained re-purposed to provide space for one or more rows of containers on deck within a given length of ship.

Fig. 10 shows an arrangement similar to that shown in Fig. 8 in which the connectors 25 are replaced by alternative connectors in the form of projections 70 which overlap and extend alongside part of a side of a container in the column to be restrained. These projections are supported from the columns 83 of triangular frames 51 mounted on lashing bridges 72. The projections 70 can be rotated about an axis which could be vertical or, as illustrated, a horizontal axis 73 out of the container bay "A" during loading and unloading of the containers as shown by container 12" passing along the bay being carried by a container crane (not shown).

This rotation can be done using suitable known actuators (not shown) mounted on frames 51 or columns 83 so that the process can be operated remotely. The actuators are energised by known means. So, for the hydraulic ram, oil is pressurised by an electro-hydraulic pump through an electronically controlled solenoid valve block to the ram. As known, the ram is extended or retracted depending on which side the piston in the ram is energised. The operator located remotely sends an electronic signal to a control box which switches a strong current to the solenoids to open or close the valves to extend of retract the rams. Similarly, if the actuator is a mechanical linear actuator, then remote signals are amplified through the control box as before but then in place of the solenoid opening or closing a valve, the known electric motor in the linear actuator is driven one way or the other to extend or contract the actuator.

To improve the restraining of the columns 14 of containers more than one projection 70 can be mounted on the frames 51 or columns 83. These projections 70 may be mounted at fixed heights for example on column 83 or may be moveable vertically using actuators built into the supports for the projections. Fig. 10 shows projections 70 provided at more than one height to restrain the eighth and fifth high containers in the stacks and are also deployed in the gaps "B" between the stacks 77 of the columns. The projections 70 each have a tapered nose end 70a which assists when entering the gaps

"B" which can vary due to manufacturing tolerances, general clearances, movement of the ship and other practical reasons. As the projection is rotated about its axis 73 the leading edge of the tapered nose 70a enters the gap "B" and if required wedges the adjacent stacks 77 apart to allow full entry of the projection into the gap.

Projection 70' is also shown in Fig.10 which is restraining the other end of container 12 with a further projection 70” in an inactive vertical position clear of the container bay A. Three further variants are also shown in Fig.10 one being a double ended projection 74, which can pivot about a transversely extending horizontal axis 74a located midway between its ends so that it can restrain the ends of two containers when moved through 90 degrees from its inactive vertical position shown in Fig. 10. Secondly a projection 75 is also shown which is provided with a plate 76 which can hold a column of containers down when rotated clockwise from its Fig. 10 position so that plate 76 lies above the top container in a column. Thirdly a projection 70”' is located midway up the column 83.

In Fig. 11 a preferred example of the restraining means again comprises pivoting projections 80 pinned to the columns 83 by pivot pins 96 with axis 74 and which projections have double tapered ends 81 and which can be moved between their working (horizontal) and non-working (vertical) positions by hydraulic rams 82. When moved to the projecting position the projection 80 abuts a support 68 on the column 83 to stop further rotation due to a container acting upon it during handling or sea transport.

These projections 80 are supported on columns 83 of appropriate height secured to the deck between the transverse rows of the stacks of containers or at their ends. This arrangement allows the container bay "A" to easily cleared for loading and unloading of the containers using the rams 82.

Although pivoted projections 70 are preferred, it is envisaged and illustrated in figure 16, that the projections could be linearly displaceable. In Fig.16 two columns 83, shown brought close together for illustration purposes, support two restraints each comprising a housing 86 fixed to its column out of which telescopes horizontally a projection 85 to restrain container 12 by acting on the side 89 of the container, also shown reduced in length for illustration, between the two columns 83. The projections 85 stop sway in the direction of arrow S of Fig. 16 and are driven in and out by a known double acting hydraulic ram with cylinder 87 and rod 88.

Figs. 12 and 13 show how the vertical position of pivoting projections 90, similar to the projections 80, can be moved vertically up and down columns 83 on platforms 93 by rams 91. Platform 93 has fixed to it, vertical side plates 95 (near side cut away to show the interior of the assembly) which carry the pivot pins 96 with axis 74 of the projections 90, so that as the platform is driven up and down the projections are carried with it and can be deployed independently of the platform location.

It is envisaged that if the platforms are not required to have vertical position adjustment, the projections or side plates can be pinned directly to the columns 83.

The width "W" of the projections 90 can be varied from say W1 to W2 by fixing on packing pieces 92 or if the packing pieces are fixed on projections 90 they can be provided with in and out screw adjustment 94 to move the packing pieces in or out to cater for different gaps "B" between the stacks of containers perhaps resulting from the stacking of containers with different widths typically 8ft to 2.55m wide.

Fig. 14 shows a container 12 being removed from an end column of containers 14 by a crane spreader 18 with restraining means in the form of pivoting projections 100 still active to stabilise the lower portion of the column during the removal of the container. The projections 100, which pivot about horizontal axes 106, are also moveable up and down the vertical columns 101 of frames 102 located between the rows of stacks 103 of containers 12 using rams or suitable mechanisms 104. As seen in Fig. 14, the projections 100 are in their inactive positions when vertically orientated and are in their active positions when horizontally oriented. End frame 102' has single projections 105 which pivot about horizontal axes 107. The height of the projections can be set or moved vertically to best restrain the stacks which can vary in height due to differences in container heights or the number of containers stacked in a column. The pivoting projections 70, 80, 90 and 100 can be set in the far end of a bay in their active position so that containers 12 being loaded can be quickly loaded up against them to speed the otherwise slower time need to locate the first container in the far end stack.

In extreme service as the columns of containers begin to sway substantially each stack column can lean on the adjacent column and adjacent stacks of columns also lean on each other.

It will be evident from the above that lashing devices and systems in accordance with the present invention offer the prospect of having a completely automated arrangement with no need for manual assembly or disassembly of lashing bars by stevedores on loading or unloading containers giving significant cost and time savings.

As containers have a high torsional stiffness in a horizontal plane it is feasible that in some shipping trades container loading might allow restraining of the containers at only one end to be sufficient to stabilise the stacks of containers. This will again save time and money in port.

It should be appreciated that it is most commonly the outermost columns of containers that fall overboard in extreme rolling events. So it is envisaged that if a ship is rolling to a dangerous level and the outermost columns restrained by a projection, as the ship rolls to say the right and the columns bear on a given projection, then as the roll reverse to the left, the said projection is now relieved of the bearing load and can be opened by driving its actuator to the open position such that on return to the right, the containers can then be allowed to fall overboard thus relieving the capsizing moment on the ship.

Alternatively, if it is desired to have a restraining means able to be released instantly because of an emergency situation such as during a capsizing motion resulting from say a shift in cargo to one side of the ship, then it is envisaged that an emergency button or other control member, preferably is located on the bridge of the ship or at additional locations. The button or control comprises a switch which closes an electronic circuit that drives a signal to a detonator to detonate a percussion device mounted within the support structure of the restraining means such that when detonated the support structure no longer restrains the container to which it is allocated and some or all the containers adjacent to the restraining means are released for discharge overboard. Either way, if is it judged by the ships master or other person or by a sensor set to detect if the ship is in danger of capsize due to excess rolling of the ship and/or sway of the columns, the release system is arranged in such circumstances to deactivate an appropriate part of the lashing system to allow some containers to fall off the ship to restabilise the ship.

Additional restraint can be achieved by combining lashing bars as in the prior art to a ship fitted out with the lashing devices of the present invention. Also, if operating conditions require it, the various constraints of the present invention can also be used on both ends of the containers being restrained as shown in, for example, Fig.10.

Claims

1) A container lashing device for securing columns of containers on the deck of a container ship against transverse sway, the device comprising a support means secured to the deck and carrying restraining means engageable with a container in a column of containers to restrain transverse sway of the column in at least one direction, the restraining means being moveable to disengage the container to allow unloading of the column of containers whilst still being supported from the support means.

2) A device according to claim 1 in which the support means comprises a frame whose base is supported from the deck and which carries one or more restraining means.

3) A device according to claim 2 in which the restraining means comprises a connector in the form of a projection which overlaps and extends alongside part of a side of a container in the column to be restrained.

4) A device according to claim 3 in which the projection is pivotable on the support means to a position alongside part of the side of the container to be restrained by a pivot actuator mounted on the support means.

5) A device according to claim 3 in which the projection is linearly displaceable on the support means to a position alongside part of the side of the container to be restrained by a linear actuator mounted on the support means.

6) A device according to any one of claims 2 to 5 in which the support means carries projections at more than one height to offer additional restraint against transverse sway.

7) A device according to any one of claims 3 to 6 in which the projection has a gap set between it and the side of the container to be restrained to allow the column to build up some resilient bias against sway before engaging the restraint of the projection.

8) A device according to any one of claims 2 to 7 in which the or each projection is double ended and pivots about a horizontal axis located midway between its ends so that it can restrain the adjacent ends of two containers in adjacent columns. ) A device according to any one of claims 2 to 8 in which the or each projection pivots about a horizontal axis and has a tapered end so that it can more easily be inserted between adjacent stacks of containers. 0) A device according to any one of claims 2 to 9 in which a projection has a top plate which when the projection is in its operative position extends above a top container in a column being restrained thus holding down the column. 1) A device according to any one of claims 2 to 10 in which the restraining means is supported from the deck on a support column or frame located between rows of stacks of columns extending across the deck. 2) A device according to claim 11 in which actuator means carried on the support column or frame can pivot the projection from a position alongside part of the side of the container to restrain the column of containers to a position clear of the container to allow loading or unloading of the column of containers. 3) A device according to claim 11 or 12 in which the or each projection is moveable vertically relative to the support column or frame by height actuator mounted on the support column or frame. 4) A device according to any one of claims 11 to 13 in which the support columns which support the actuator means are built into frames which extend transversely across the deck of the ship between the rows of the stacks of the columns of containers.5) A device according to claim 1 in which the support means comprises a longitudinally telescopic boom, a lower end of the boom being supported from the deck and an upper end of the boom carrying the restraining means. 6) A device according to claim 15 in which the telescopic boom comprises sections which can be moved relative to each other by telescoping means to change the effective length of the boom. 7) A device according to claim 16 in which the telescoping means comprises an electrically and/or hydraulically operated actuator connected between the boom sections. 8) A device according to claim 17 including damping means to cushion the boom against shock loads experienced when the sway of containers changes direction. ) A device according to any one of claims 15 to 18 in which the lower end of the boom can pivoted relative to the deck of the ship about a generally horizontal axis by a boom elevation actuator. ) A device according to claim 19 in which the lower end of the boom can also be pivoted relative to the deck about a generally vertical axis by a boom swing actuator.) A device according to claim 19 and 20 in which the lower end of the boom is mounted on a turntable which can rotate about the vertical axis and which also carries the horizontal pivot axis. ) A device according to claim 19 or 20 in which the actuator is electrically and/or hydraulically operated. ) A device according to any one of claims 15 to 22 in which the boom has a camera near to the connector to facilitate location of the connector with the aperture. ) A device according to any one of claims 15 to 23 in which the upper end of the boom has a ram adjacent the connector to contact the corner fitting and push the connector away from the corner fitting to assist in releasing the connector. ) A device according to any one of 15 to 24 in which the upper end of the boom has a known electromagnet or mechanised magnetic switchable device which when activated draws the connector towards the corner fitting to assist in engagement with the corner fitting aperture. ) A device according to claim 2 or any one of claims 15 to 25 in which the restraining means comprises a connector for engaging an aperture in a corner fitting of one of the containers in a column to be restrained against transverse sway. ) A device according to claim 26 in which the connector comprises a twist lock for insertion into the aperture in the corner fitting, the twist lock having actuator means for rotating the twist lock once inserted into the aperture to lock the corner fitting to the upper end of the boom. ) A device according to any one of claims 1 to 27 in which the support means is connected with the deck via a lashing bridge which extends transversely across the deck and upwards alongside the ends of the lower containers in the columns being restrained. ) A device according to any one of claims 1 to 28 which has a position control system for allowing the restraining means to be set to engage with a targeted part of the container to be restrained. ) A system for restraining transversely spaced stacks of containers grouped in side by side columns forming rows extending across the deck of a container ship with at least some of the stacks of containers in a given row having lashing devices according to any one of claims 1 to 29 arranged to restrain transverse sway in one direction and other stacks in said row having lashing devices according to any one of claims 1 to 29 arranged to restrain transverse sway in a second and opposite direction. ) A system according to claim 30 in which lashing devices in accordance with any one of claims 1 to 29 are deployed at both ends of at least some of the containers in the stacks. ) A system according to claim 30 or 31 in which an emergency release system is provided to enable one or more of the restraints to be released rapidly if the sway occurring is judged manually or automatically likely to lead to the ship capsizing, the release system being arranged in such circumstances to deactivate an appropriate part of the lashing system to allow some containers to fall off the ship to restabilise the ship. ) A system according to claim 32 in which operation of an emergency control member detonates one or more percussion devices to render the appropriate restraining means inoperative to allow the containers to fall off the ship. ) A system according to any one of claims 30 to 33 and having fitted in addition lashing bars to the lower containers in at least some columns to provide additional restraint to those columns. ) A system according to any one of claims 30 to 34 in which the restraining means are engageable with both ends of at least some of the containers to be restrained against transverse sway.