container carrying interests. The Classification- approved plans allowed 6-high stacks in the holds, so 6-high stacks were used throughout. Not a single charterers’ superintendent bothered to check the stack plans, so many heavier units were placed in the upper three tiers because of the port discharge rotation. A week before arriving at the first discharge port the base tier containers in Nos. 2 & 6 holds suffered widespread collapse and crushing and tank-tops were pierced. Investigation revealed that the approved stacking plans provided a sliding scale, in which unit height increase should have been traded off against unit weight decrease: 20ft base and second tier units should not have exceeded 20 tonnes; third tier units should not have exceeded 10 tonnes, fourth tier units should not have exceeded 6 tonnes, and the two top tiers should have been empty. Sad to say, anything learnt from that loss appears to have been quickly forgotten bearing in mind that a similar train of events occurred in the same vessel some twelve months later.


The records of all the P&I Clubs combined would reveal the unwelcome frequency with which a similar sequence of events has created widespread damage and loss to containers carried on the weather-decks, and continues to occur. Don’t overload the stack. Consult the stacking plans. A container constructed to accept 8 empty units above it (a total of 20 tonnes) is unlikely to withstand a superincumbent weight of 160 tonnes even when static; when subjected to vertical acceleration/deceleration forces at sea, collapse is almost certain to occur.


Thirdly, where two 20ft units are stowed on the weather deck in what would otherwise be a 40ft unit position, it is very difficult – in many instances, impossible – to apply wires, chains or bar-lashings to the adjacent end-butting corners. Their absence is not compensated for by using double or four-way inter-layer stackers (spades) or longitudinally positioned screw- bridge fittings, tie-wire, or the like. (Fig. I).


The problem is that the container stack as a whole, and particularly those units in the base tier, will be subject to excessive wracking stresses should the ship start rolling in heavy seas or pronounced swell conditions. Some compensation can be applied by the use of anti- rac bands (two tensioned metal straps fitted diagonally across the corners of the ‘free’ ends of the base tier containers) but they suffer from the same inability to secure the ‘butting’ ends. A full lashing system, properly planned for the dual carriage of 20ft and 40ft units is to be preferred if container losses from this cause are to be prevented


When all else fails – read the instructions! 6


Substandard components jeopardise cargoworthiness


A vessel’s container stowage and securing arrangement can be easily undermined if substandard and/or incorrect components are utilised. To maintain securing equipment in good order, both fixed and portable, requires considerable time and effort.


Whatever regulations, standards or codes of practice are issued the integrity of a vessel’s container stowage and securing arrangement can only be made by regular inspection of the securing equipment. The securing arrangement can amongst other things be undermined by one or more of the following:


● ‘Rogue’ securing equipment; ● Improperly maintained securing equipment; ● Insufficient supply of correct securing equipment; ● Overloading of the securing equipment.


Portable securing equipment


The human nature of stevedores means that they will often use the first item of equipment which comes to hand, be it ‘rogue’ or damaged, without due consideration to its suitability. If substandard equipment is used it can fail at a lower load than its design rating, thereby resulting in a failure of the overall securing system and the possible collapse of the container stow.


The aspects which should be considered during periodic inspection of container securing equipment should include the following:


● Inspection of the twistlock complement to ensure that ‘rogue’ twistlocks, i.e. ones with an opposite locking action to the ship’s standard complement, have not made their way onboard. When left-hand


Mixed twistlocks


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