What is Container Lashing?
Containers are the most transported cargo form worldwide as they are transported by all the three transportation systems available, i.e., land, air, and water. This makes container handling of different dimensions on ships very critical as they are subjected to harsh weather conditions and strong winds in the sea. When a vessel is in a seaway, it is very likely to incur three main movements – rolling, pitching, and heaving. These movements give rise to accelerations and forces, which act on the container frames and lashing system in use. Due to forces acting on containers and their lashings, the separation force is the tipping force that works to loosen or separate the corner fittings or twist locks.
If the storage of cargo is not secured correctly during transportation, there would be a high risk of shipping containers falling overboard into the sea, inflicting damage to other loads nearby, as well as the vessel’s structural and fittings. Improper cargo lashing and failure to follow cargo stowage standards on ships will result in endangering property, lives, and the environment at sea.
Container Lashing is the process of securing containers together on a ship. It is one of the most significant risks in the marine cargo handling sector, with injuries and lives lost every month. When a container is loaded over ships, it is secured to the ship’s structure together with the container placed below it through lashing rods, turnbuckles, twist-locks, etc. These twist locks are inserted into the corner castings of the containers with elongated holes where the rotating lug of the twist-lock engages, locking the containers together. This prevents the containers from moving or falling off into the sea during rough weather or heavy winds. Securing cargo using dunnage bags and composite strapping is also essential to prevent goods from being damaged by impact.
Even with technology systems available, container lashing and securing remains largely manual, requiring lashing specialists on deck and ashore to be involved. This is a hazardous operation, and risks multiply as vessels grow in size and ports and terminals face more extensive call exchanges. Recent vessel casualties have also highlighted the forces encountered by large ships at sea and the problem of containers being damaged or lost overboard as lashings fail. Hence, it is crucial to know the basics and follow safe container lashing regulations.
Container Lashing Equipment
Load the shipping container over the base twist lock and ensure that the wire handle is in the lock position. To remove, pull the wire all the way, tilt the twist-lock backward and lift the twist-lock from the socket.
Semi-Automatic Twist Lock
These twist locks are used in between the containers. When a container loads on top of other containers to form a stack, a semi-automatic twist lock is inserted between them.
Lashing rods are rods of different lengths to hold the containers from one end and are tied up to the deck surface from the other end. They are used in combination with turnbuckles to tension a ship’s container lashing. The turnbuckle on its turn is tied to the ship’s deck with a lashing plate.
Turnbuckles are used to tension a ship’s cargo container lashing. The securing device has two screw ends, of which one is welded to the ship’s deck with a lashing plate. The other screw end is attached to a lashing bar, connected with a container corner casting. By rotating the frame of the turnbuckle, the tension can be adjusted. There are two types: the knob type and the open body jaw/hook type.
The tool is used when a twist-lock cannot be unlocked by pulling the wire handle. It is used so that the emergency tool is in a position that will keep the twist-lock open, and the Container lifts along with the device.
It is a compound that should be applied to all the lashing equipment required to ensure they are well maintained and operational.
Who does the Container Lashing?
The lashing specialist oversees the lashing and de-lashing of the containers. The people commissioned to work with lashing and de-lashing of cargo should be qualified and trained. There should also be clear communication between crew members during lashing activities. Several Container lashing incidents have taken the lives of seafarers in the past. Handing cargo containers is not an easy job and needs good safe practices to carry it out safely. Below are some safety tips for lashing operations.
Safety Precautions for Safe Lashing and De-lashing Activities
- Wear proper Personal Protective Equipment (PPE) to protect yourself e.g., reflective vest, steel toe shoes, hard helmet, gloves, etc
- Work platforms, railing, steps, and catwalks should be inspected before operations
- Stretch and warm up your muscles before performing physical work
- If possible, use a back support belt and use the knee to lift
- Be cautious when walking near the ship as there may be hazards
- Do not walk under suspended loads such as gantry and hanging containers
- Clear communication and understanding of hand signals are important
- Lashing specialists planning and supervising the stowage and securing of cargo should have a sound practical knowledge of the application and content of the Cargo Securing Manual (CSM)
- The safe stowage and securing of cargoes depend on proper planning, execution, and supervision
- Only lashing specialists should spanner tight the lashings
- Lashings and securing should be per CSM guidelines
- Be careful while walking over the rods and twist locks while working. Always keep the lashing equipment in their assigned place or side of the walking path
- Be careful of fall hazards when lashing outside containers on the hatch cover or pedestal.
- Fall arrester or safety harness must be used by workers when operating aloft
- Always be at a safe distance from co-workers during lashing or unlashing containers as the long rods can be hazardous if not handled properly
- It is a normal practice not to lash or unlash anything closer than at least 3 containers widths away from other co-workers
- Do not loosen a turnbuckle and leave the rods hanging. When securing a rod, the turnbuckle must be tightened right away
- Always work in pairs when handling rods and turnbuckles
- Always report defective lashing gear, defective ship’s railing, or any other inadequate structure or system involved in the operation to the concerned person or ship’s staff
7 Points to Take Note of while Securing Cargo
- An excellent tight stowage of cargo containers on ships may prevent the need to completely secure it only if the cargo is appropriately packaged and there are no heavy components
- It is still required to secure large and heavy units even if the area surrounding them is packed with other cargo as there are possibilities of such units moving or falling
- Independent lashings must be adequately secured only to appropriate strong points of the ship’s fittings and structure, ideally the specified lashing points
- Before stowing, make sure the stack weights are correct as it is critical not to exceed the stack’s permitted weights. Else, the deck container base of the stack could collapse. If the stow is too heavy, the lashings may not be strong enough to keep the containers secure if inclement weather occurs
- Examine containers for defects, significantly the corner posts. The corner posts must withstand significant compression forces caused by static weights from stowed containers on top, as well as dynamic forces generated by the ship’s rolling, heaving, and pitching. (Reject damaged containers as containers with defective corner posts are prone to falling)
- Never overtighten lashing rods. Overtightening can put the lashing rods under excessive strain, increasing the pre-tension by a few tons, which can cause them to collapse when under load
- Avoid loading heavy containers above light containers and at the top of a stack