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Lashing requirements on board container ship - care of lashing devices

container stowage
container stowage

Containers loaded under deck in cellular vessels are constrained by the cell guides, landed one on top of the other and require no further securing. A considerable number of ships also have cell guides that extend above the weather deck and they too require no further securing. Containers stacked one above the other without the benefit of cell guides must be secured one to the other with twist locks, and/or a combination of locating cones, bridging pieces, lashing rods, wires and bottle screws to prevent shifting.

The securing of containers on (or, if applicable, below) deck is the responsibility of the ship's staff though not necessarily carried out by them whether the ship is a purpose-built container ship or another type of ship carrying containers.

It is important that all rod and wire lashings are sufficiently tight but not too tight to strain fittings, containers, etc. The correct bridging pieces, twist locks, etc., should be checked in position between tiers. It should be ascertained and clearly understood by both ship's and shore staff which way twist-lock handles are turned for locking, i.e. the locking position should be in the same direction for all twist-locks on the ship so that a quick glance will ensure that the locks are indeed engaged.

Recent concerns over losses of containers from large container ships have focussed particular attention on fully-automatic twist-locks and the possibility of failure of such equipment. Research has indicated that fully-automatic twist-locks may be susceptible to disengaging when subjected to the large dynamic forces experienced by large containerships operating in heavy seas. Contributory factors may be the mixing of containers of different dimensions and the effect of endeavours to reduce handling costs.

Ships' staff should ensure that all lashings required in accordance with the ship's lashing plan are put in place to minimise the possibility of losses. Additionally, there may be occasions when planners seeking to minimise container moves give heavy units top stow. This may not only cause stability problems, but excessive lashing strains when rolling, pitching or working in a seaway. While some of these factors may be outside their control, ships' officers should be alert to improper stowage and not hesitate to bring it to the attention of ship planners.

With the increased height of containers stowed on deck (up to eight tiers) the problem of safely securing the stacks has now been addressed with the construction of substantial steel lashing bridges which may extend to a height of three tiers above the deck and thus enable the tiers above to be lashed to a secure structure with the added benefit of providing a safe platform for personnel engaged in lashing.

The blocking in of containers in a stow with unitised or general cargo has already been mentioned and to facilitate this and spread the load on the container sides, large inflatable dunnage bags might be used to advantage.

Containers that are not blocked in must be properly secured with wire, rod or chain lashings to prevent any movement and to reduce the racking strains on the container. When lashing containers in conventional stow or on deck, particular attention must be paid to securing the bottom of the container as well as the top corners. This is particularly important if two or more containers are stowed in a vertical stack. It is also important that only the corner castings are used to secure the container. A wire lashing passed over the top middle section of a container does not secure it adequately and will damage the container should it move. Ships that have been designed to carry containers either below or on deck but do not have cell guides, will have deck fittings suitably placed for corner castings to be held. It is essential that container shoes, stacker cones, and twist-locks are properly maintained. Twist-locks must be correctly engaged, normally by rotating the locking mechanism through 90. The lashing plan provided by the ship builder should be strictly adhered to, particularly when containers of varying heights are loaded.

All container securing equipment (chains, rods, twistlocks, shoes, cones, etc) must be inspected at regular intervals with maintenance carried out as necessary with appropriate records maintained. In large ships this may be impossible for the ship's staff to carry out and owners should make appropriate arrangements. It may be necessary for equipment to be landed for inspection by properly trained personnel in a shore establishment.

Ro-Ro ships that may carry cargo either on wheels or landed directly on the deck will usually be fitted with securing points that can be used for either type of cargo.

Cargo Securing :

It is essential that prior to proceeding to sea all cargo on board is adequately secured to prevent it moving and endangering the safety of ship and crew. Particular cargoes and particular ship types may require specialised securing and the IMO Code of Safe Practice for Cargo Stowage and Securing, 2011, (CSS Code) provides guidance on stowage and securing of particular commodities (e.g. portable tanks, wheeled cargo, locomotives, coiled sheet steel, metal scrap in bulk, logs, etc.

Additionally, the Code provides guidelines for the preparation of a Cargo Securing Manual "... appropriate to the characteristics of the ship and its intended service..." This means that each ship must be provided with a manual that is written for that particular ship. Information in the manual must include:
It is not possible for ships' staff to examine or monitor the securing of cargo within a container although the Master has the right to open a container for inspection should he suspect that all may not be well within. Cargo which is visible (such as that on flatracks) can be examined prior to loading and any lashing arrangements which are suspect may be adjusted or the unit rejected until properly secured.

containership lashing pattern
Fig: Containership lashing pattern

Containers stowed on deck requires particular care in stowage and securing, whilst at the same time affording adequate access to sounding pipes, fire hydrants etc., and to the ship's side should the need to jettison arise. At sea, all containers on deck should be inspected daily and lashings tightened when required. In general, it is not desirable to carry steel cargoes on deck (including in flatrack containers) as they are particularly susceptible to the moist salt air and maintaining covering in heavy weather often proves impractical.

When containers are carried on deck, the ship is required to be approved for that purpose and the containers themselves are secured with twistlocks and lashings. These usually consist of steel rods and turnbuckles. Lashing pattern to be followed on board is detailed in the vessels cargo securing manual.

When containers are carried below deck, the containers are slotted into cell guides on a cellular container ship. When carried within a cell guide framework, no further external support is generally required.

When 20 containers are stowed below deck in 40 cell guides it may be necessary to over-stow the 20 containers with a 40 container. The Cargo Securing Manual should be consulted before loading.

Vessels lashing requirement as per the cargo securing manual must be informed to the terminal staff, stevedoring company as required and if necessary copies of the Lashing Patterns must be provided.

There must be a clear understanding as to the vessels lashing requirements in order to avoid delays and non compliance with cargo securing requirements.

Unused cargo loose securing devices after discharging containers must be stowed away safely in designated lashing bins on deck. After cargo operations are complete, it must be ensured that no loose securing devices are lying on container tops, hatch covers or such places so as to pose a potential threat of injury or damage.

lashing-bridge
Fig: Lashing bridge

Ships lashing gear must be well cared for and crew must always be vigilant to avoid loss of lashing material. These are mainly lost due to pilferage, damage, gear being left on the quay and not returned on board and twistlocks remaining on discharged containers carried away to the yard.

Lashing bridge A strong steel structure installed between hatches to permit the stowage of an additional tier of containers or heavier containers in the upper tier. Lashings can be applied at a higher level but can also remain short.

Container lashing

Certified container lashing components must be in place for safe and efficient lashing of containers. Defective equipment must be replaced immediately. It must be ensured that deformed hooks are not used. It is also dangerous to overlook the wastage of steel on securing devices as that would reduce the strength of the lashing arrangement.

Crewmembers should ensure that the lashings are well maintained and lashing devices are kept in good condition.

Stevedores are usually responsible for lashing and de-lashing jobs in the port, however, due to lesser port stay and time constraints, crewmembers are also responsible for this operation. While conducting lashing and de-lashing operation, crewmembers should wear Personal Protective Equipment (PPE) such as a reflective vest, steel toe shoes, hard helmet, gloves etc. They should also stretch and warm up their muscles before conducting this strenuous physical job in order to avoid a muscle pull or injury.

Use of a back support belt is a must during lashing and de-lashing operations and the crew should be cautious while walking around the ship as the vessel's structure could lead to a tripping hazard. It is also important for crewmembers to understand the plan and order of the lashing and unlashing operation. It should be kept in mind that reefer containers always require more attention and co-ordination for plugging and unplugging during loading or unloading operations.





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