Container ship Cargo Securing Devices - How to Use Appropriate Lashing Gear
A ship sailing in a seaway has six degrees of motion: surge, sway, heave, roll,
pitch and yaw. The ship itself bends and twists as waves pass. Hatch covers
move relative to the hatch openings, and container stacks move as clearances
in the lashing equipment are taken up. It is the lashing system alone that
resists these movements and attempts to keep the containers on board.
Lashing systems are put to the test during bad weather when failure may
lead to container loss. Indeed, the growing number of containers lost
overboard has caused concern throughout the marine industry. Cargo claims
have increased, and floating containers pose a hazard to navigation. Masters
need to understand the strengths and weaknesses of container securing
systems. Masters must be aware of what can be done to prevent
container loss.
Ships need to be fit to receive containers, with their lashing equipment in
good order. Lashing areas need to be safe places for ships' crews and
stevedores to work.
Below is our guideline on container securing systems,
the causes of lashing failure, and how losses can
be minimized.
Motions on a seaway
Containership cargo securing devices consist of portable securing devices and fixed securing devices.
Fixed fittings are Stacking cones, foundations, deck foundations, lashing plates, lashing
eyes, lashing pots, d-rings. Fixed fittings are integrated into the hull structure or fitted on
the double bottom or hatch covers.
Loose fittings are Twistlocks, stackers, bridge fittings, tension/pressure elements, spanners,
lashing rods and turnbuckles.
Open turnbuckles combined with multi knob rods are used to secure containers of different
heights with one-rod length. For rapid adjustment and safe connection, the turnbuckle is
equipped with a slide nut. 50t breaking load systems are used almost exclusively (26mm rod
diameter).
Regular inspection and maintenance of ship cargo securing devices must be carried out. These would include a routine visual examination of components being utilized, lubrication of securing devices, repair of damaged securing devices, and separating and rejecting damaged/unusable securing devices.
An appropriate number of portable securing devices shall always be kept on board. Usually the number of securing devices required on board is governed by figures provided in the vessels cargo securing manual (for max capacity loading). Alternatively if the vessel operator requires a smaller quantity of cargo securing devices to be maintained on board, then that quantity shall be maintained.
The consideration in such case is usually the amount of cargo being carried in the given trade. However in any case, cargo that cannot be secured in accordance with the requirements of the Cargo Securing Manual due to shortage of securing devices shall not be carried.
Lashing gears- fixed fitting
Lashing gears- loose fitting
Lashing gears- loose fitting-twistlock & midlock
A proper inventory and inspection report for securing devices as required by the vessels cargo securing manual shall be periodically prepared and forwarded to the vessel operator.
Securing devices not belonging to the vessel must not be used as they may not conform to the vessels Cargo Securing Manual. There is a perennial problem of right hand and left hand twist locks finding their way on board the vessel and this can undermine the integrity of the securing arrangement.
The vessel must only have One Type of Twist lock and all of the vessels Twist locks must be painted for easy identification.
Defective securing devices shall as far as possible be repaired on board and if not possible then these shall be condemned. Shortfall of cargo securing devices shall be reported through the inventory and inspection report and requisition raised to make good such shortfall.
Various lashing devices that are common onboard containerships are explained below:
Fig: Semi-automatic twistlock
Twistlock – A mechanical locking device at the corner of a container. Conventional twistlocks
are locked and unlocked manually with operating rods. Rotating the movable part around
a vertical axis locks the device and a container to a twistlock foundation on a hatch cover
or another container. Reversing the motion effects unlocking.
Semi-automatic twistlocks are locked automatically and unlocked manually by the
operating rods. Fully-automatic locks are placed in the lower corners of the container
at the pier. They lock automatically after the container is placed on the top, and unlock
automatically when the container is lifted.
In fig right: SAT CV-20 is a fully symmetrical semi-automatic twist lock developed by MacGREGOR. When
containers are loaded at a fast rate, incorrect insertion of twist-lock will cause significant danger and
delays in the cargo handling process. The CV-20 twist lock can be inserted into the container
corner castings either way-up – the incorrect insertion is not possible.
Container Securing
On cellular container vessels, containers are put down cell guides and landed one on top of the other. No further securing is generally required. Similar cells may also exist on deck, but containers stacked on top of each other without the benefit of cell guides must be secured one to the other with twist locks and a combination of twist locks, lashing rod, and turnbuckles.
An approved Cargo Securing Manual (CSM) will be available on board, which must be followed to ensure correct lashing and securing of the container cargo. The Cargo Securing Manual must be referred to keep a proper check on the height check of the stack to avoid any damages to the containers while pontoon securing. It is quite often missed out when the stowage plan is issued by the planner. The responsibility lies with the duty officer for supervising the pontoon securing.
An inventory is to be maintained on board of all lashing equipment and stocks replaced without delay in cases of loss or damage.
Minimum quantity of lashings
The Cargo Securing Manual issued on ship's delivery does not detail the minimum quantity of portable securing/lashing devices that should exist onboard. There is no minimum industry quantity of lashing stipulated nor guidance on the required percentage of spares. The minimum quantity of portable securing/lashing devices is defined by the commercial needs of the ship and therefore, the minimum quantity of portable securing/lashing devices is that required to secure the intended stow of containers following the lashing pattern given in the approved CSM.
The list/plan of cargo securing devices in the CSM is to be appropriately updated to correspond to the actual arrangement/number of cargo securing devices, including some reserve supplied on board*. These amounts should be corresponding at all times. Approval of the Cargo securing manual update of the list/plan by class is not necessary. A sufficient quantity of reserve cargo securing gear should also be available onboard the ship
Where there are insufficient lashing devices available onboard, the respective containers affected will not be loaded.
*according to the guideline of 1.3.5 and 2.1.1/2.2.1 of MSC.1/Circ.1353/Rev.1
Note: - Securing/lashing must always be as per the approved lashing plan.
Lashing devices must be of a certified type and in acceptable condition.
Our additional pages contain somewhat larger lists of resources where you can find useful informations
Containership operation : Cargo Securing There are six degrees of motion at sea that a ship may have to encounter in a voyage. However, pitching, heaving, and rolling are three major forces that impact most on a containership's lashing arrangement. Lateral rolling motion factors the greatest challenge for piles of containers. If containers are to be carried safely on the deck of a container vessel, they must be tightly connected to the ship. It is done with the aid of devices known as twist locks.
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Containership operation : Common reasons for stowfall
Container stows often fail due to container stacks being too heavy and too high overall, exposing the lower containers to excessive transverse racking and compressive forces due to the tipping effect. Such an anomaly may occur if the ship is unable to calculate the forces acting on stow with precision. The Cargo/Container Securing Manual is limited in this respect as the examples of container weight distributions shown may not cover all permutations and eventualities. Software programs have the advantage of taking into account all known variables........
Containership operation: Cargo hold ventilation
Cargo holds ventilation onboard a containership is very important as it minimizes the risk of harm or damage to cargo. A proper ventilation system assures the quality of the transported goods by preventing the formation of condensation in cargo spaces, reducing the harmful heating of the shipment, and removing potential hazardous gases from cargo spaces........
Containership operation: Safety of personnel
In port stevedores board the vessel for lashing, unlashing and cargo operations and their safety whilst on board is the vessels responsibility. It is important to understand that any injury caused to stevedores or shore personnel due to a condition on board being unsafe, can result in very large claims to the vessel.
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Containership operation: wet damage in cargo hold When water entered into a ship's cargo, hold it may cause wet damage to the cargo inside containers especially to those stowed on the bottom stack, unless the bilge water is drained in a proper and swift manner. The regular sounding of bilge well or monitoring bilge alarm must be one of the very important or rather essential routine jobs on board. However, this job requires special attention on board. All bilge alarm need to be tested regularly......
Reefer cargo care at sea Unlike permanent cold stores or refrigerated ships, where robust equipment is under constant care by qualified personnel, the ISO refrigerated container may travel by several different modes and be in the care of many and varied people. Before being despatched to load refrigerated cargo (usually at shippers' premises), the container and its machinery should be subjected to a rigorous examination.......
Containership cargo stowage and planning Master and officers of all vessels require a good working knowledge of the various kinds of cargo they are likely to carry their peculiar characteristics, liability to damage, decay, or deterioration, their measurement, and the usual methods of packing, loading and discharging, stowage, dunnage, etc., as the Master is responsible for the safe loading of his vessel and the proper storage of the cargo......
Stacking Weights Restrictions
rior loading cargo, stacking weights of containers must be checked against the allowable stack weights on board the vessel both on deck and under deck. Neglecting above may cause serious damage to ships structure, hull and eventually overall stabilty of ship may get affected. Maximum allowable stack weights of Tank tops, Hatch covers and Decks shall not be exceeded at any time......
Lashing strength calculation Lashing strength of deck cargo shall be ascertained by using the appropriate lashing strength calculation software where provided. All resulting values for lashing strength must be within the tolerance limits prescribed by the vessels classification society......
Dangerous goods stowage and segregation Clear guidelines apply to the stowage and segregation of Dangerous Goods and in some cases may require particular commodities to be carried in completely separate holds. The interaction of two cargoes will not occur if the packaging of that cargo remains intact. However, the Master must always consider the possible effect should the cargo escape for any reason and should not restrict his consideration to those cargoes which are listed in the IMDG Code......
Reefer Container Stowage
Reefer containers proposed for stowage must be accompanied by a reefer manifest. This reefer manifest should contain Container No., Stow position, Commodity, Temperature, and Ventilation status......
Out of Gauge Container Stowage
It is essential that, during out of gauge cargo operations, a careful watch is kept for any damage caused to the vessel, her equipment, or to containers. Notice of any damage must be immediately brought to the attention of the Stevedore's representative, the Port Captain/Supercargo and Charterers Agent. Damage reports must be completed in all cases giving the full and comprehensive details of damage caused......
Special Container Stowage After receiving stowage plan ships, Chief Officer must ensure that all Deck Officers are aware of any specialized containers due to be worked, such as reefers, vents, over-heights, over-widths, flat racks, etc. and their unique requirements.....
20 or 40 or 45 feet Compulsory Stowage Locations
Most cargo securing manual provide a guideline for different container types. These stow positions of 20 feet,40 feet, or 45 feet are also incorporated in a ship-specific stowage planning software and highlight errors if any violations occur......
Irregular Stowage of Containers
The Terminal Planner shall present the pre-loading plan to the Chief Officer to obtain his approval/comments. The Chief Officer, in turn, enters the cargo data in the loading computer and must ensure that the required criteria, concerning stack weights, trim/stability/stresses/ visibility limitations, DG cargo segregation, and specialized container requirements, are met. He should allow the bunker/freshwater consumption during the voyage and all possibilities of ballasting / deballasting. The completed loading plan must be presented to the ship's Master for approval.....
Over-stow of Containers With a closed roof, the hardtop the container offers the same reliable protection as provided by a standard box. Hardtop containers have more lashing points than other container types. This guaran- tees reliable and convenient securing of cargo.
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Other matters regarding cargo stowage as necessary Bulk products carried in a closed container might include malt, grain, seed, polythene granules, chemically inert powders, brake fluid, detergent, fruit juice, wine, non-hazardous oils, sodium silicate, fatty acids and maple syrup amongst many others......
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