Importance of proper lashing of containers on board ships

Since the inception of containerisation, the shipping container has been used to ship various products around the world.. An estimated 793.26 million TEUs were handled in container ports worldwide in 2019.. As of this article, 23.8 million TEUs are being shipped around the world in 6,136 active container ships..

evolution of container shipsThese containers are being carried on container ships that are increasing in size and capacity year after year..

Naturally, there is increased concern and focus on the safety of the ship, its crew due to the number of containers being carried on board..

There have been several maritime disasters in the last few years, some of which have been reported in detail on this site..

A few of the incidents that involved containers falling of a ship have been attributed to the lashing of containers on board or lack thereof..


One such incident in 2017 was the Ever Smart, a 7,024 TEU UK flagged container ship in which 151 containers collapsed on board causing 42 containers to fall overboard and damaging 34 containers..

It has been reported that the Master of the ship had changed the course of the ship to avoid severe weather along the journey..

The ship was rolling 10º to 12º and pitching heavily with frequent bow flare slamming due to the heavy seas, causing the ship’s crew to be confined to the accommodation block in line with the ship’s procedure..

The Maritime Accident Investigation Branch (MAIB) conducted an in-depth investigation into this incident..

The MAIB Accident Investigation Report 14/2020 which was released in July 2020 concluded that:

  • The loss of the containers most likely occurred during a period of heavy pitching and hull vibration in the early morning of 30 October ;
  • A combination of factors resulted in a loss of integrity for the whole deck cargo bay; in particular, the containers were not stowed or secured in accordance with the cargo securing manual ;
  • The container lashings might not have been secured correctly

 

CSS Code

Accelerations acting on a ship during sea voyage creates a combination of longitudinal, vertical and predominantly transverse motions and these forces is the reason for the majority of securing problems..

pack your cargo properly

The IMO recommends that the “hazards arising from these forces should be dealt with by taking measures both to ensure proper stowage and securing of cargoes on board and to reduce the amplitude and frequency of ship motions“..

In line with this, a Code of Safe Practice for Cargo Stowage and Securing (CSS Code) was adopted by the IMO in November 1991..

The Assembly recommended that the various PSCs and Governments implement the CSS Code at the earliest possible opportunity and requested the Maritime Safety Committee to keep it under review and amend it as necessary and MSC.1/Circ.1352/Rev.1 is the latest revision..

The purpose of the CSS Code is to provide an international standard to promote the safe stowage and securing of cargoes by:

  • drawing the attention of shipowners and ship operators to the need to ensure that the ship is suitable for its intended purpose;
  • providing advice to ensure that the ship is equipped with proper cargo securing means;
  • providing general advice concerning the proper stowage and securing of cargoes to minimize the risks to the ship and personnel;
  • providing specific advice on those cargoes which are known to create difficulties and hazards with regard to their stowage and securing;
  • advising on actions which may be taken in heavy sea conditions; and
  • advising on actions which may be taken to remedy the effects of cargo shifting.

The CSS code reminds us that the Master is responsible for the safe conduct of the voyage and the safety of the ship, its crew and cargo..

In a recent case of the loss of containers at sea from the APL England, the Australian Maritime Safety Authority (AMSA) did just that and held the Captain of the ship “personally responsible” for the loss of containers and charged him for the incident and took him to court..

 

General Principles of Cargo Securing and container lashing

As per the CSS code,

  • All cargoes should be stowed and secured in such a way that the ship and persons on board are not put at risk.
  • The safe stowage and securing of cargoes depend on proper planning, execution and supervision.
  • Personnel commissioned to tasks of cargo stowage and securing should be properly qualified and experienced.
  • Personnel 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.
  • In all cases, improper stowage and securing of cargo will be potentially hazardous to the securing of other cargoes and to the ships itself.
  • Decisions taken for measures of stowage and securing cargo should be based on the most severe weather conditions which may be expected by experience for the intended voyage.
  • Ship-handling decisions taken by the master, especially in bad weather conditions, should take into account the type and stowage position of the cargo and the securing arrangements.

 

The CSS Code states “Cargo and cargo units carried on or under deck shall be so loaded, stowed and secured to prevent as far as is practicable, throughout the voyage, damage or hazard to the ship and the persons on board, and loss of cargo overboard. 

Cargo units, including containers, shall be loaded, stowed and secured throughout the voyage in accordance with the Cargo Securing Manual approved by the Administration

MSC/Circ. 745 Superseded Guidelines for the preparation of the cargo securing manual says “The cargo securing devices should be maintained in a satisfactory condition. Items worn or damaged to such an extent that their quality is impaired should be replaced.“..

The inspection and replacement of these cargo securing devices is the responsibility of the ship operator and it should come with appropriate certification in the form of a type-approval system by a Classification Society or other accepted testing body..

 

Lashing onboard container ships

The “first generation” of pure container ships had cell guides in the holds, hatchcovers were fitted with lashing points and the deck had container posts to facilitate loading of containers on deck..

But because these ships did not load containers more than 1 tier in height on deck, traditional lashing methods such as twistlocks, lashing bars, stacking cones or bridge fittings were used..

However, as container ships and sizes evolved, twistlocks became the more popular method of securing containers allowing for containers to be stacked upto 3-4 tiers high depending on the weight of the containers..

The advent of Post-Panamax container ships and its large beam ushered in the use of a “lashing bridge” which is a solid steel structure running athwartships (across the width of the vessel) and placed between each 40′ bay running across the length of the ship..

lashing bridge
Image : UK P&I

Lashing bridges allows the 2nd and 3rd tier of containers to be secured to it using turnbuckles and lashing rods while the whole stack of containers is secured using twistlocks..

While the usage of all these lashing equipment, use of computer lashing software, carrying and following an approved Cargo Securing Manual, should result in a reduction in collapsed stows and loss of containers at sea, it can happen only if the ship operator maintains the lashing equipment as required and comply with the requirements of the CSM 100%..

It has been said that the vigilance of the ship’s crew in monitoring these vital aspects and ensure that the lashings are used and fitted properly is of utmost importance..

However, in this time of the COVID-19 pandemic, when some of the ship’s crew have been working non-stop more than a year due to crew change restrictions, such vigilance may be compromised as around more than 200,000 seafarers are still stranded onboard various ships possibly compromising their own safety and that of the safety of the cargo, the ship and the environment..

 

Findings of the Ever Smart

lashing of container - shipping and freight resource
Image : MAIB Report – Ever Smart

The MAIB report seems to indicate that safety issues that have been overlooked directly contributed to the accident..

As per the report, the container stow collapse was caused by a combination of factors such as container weight distribution, container lashing arrangements and the ship’s motion..

The container weight distribution was not in accordance with the stack weight tables i.e. hi-cube containers were loaded eight high in the outer stacks of the stow, and the ship’s GM exceeded the recommended full load GM..

The container stowage plan developed by the shore planners did not comply with the instructions and guidance contained in the ship’s cargo securing manual..

The weights of the containers’ allocated slots in bay 70 (where the collapse occurred) did not match or resemble the weight distribution patterns provided in the CSM..

For example, the weights in the upper tiers exceeded the values given in the stack weight tables and those in the lower tiers were much lower..

This would have caused the stacks’ centre of gravity to move upwards, and the acceleration forces acting on the lashings and containers at the bottom of the stack to increase and the stowing of hi-cube containers eight high in the outer stacks raised the height of the stacks and further increased the acceleration forces acting on the containers and their lashings.. It also increased the windage area of the outer stacks..

Many lashing rod turnbuckle lock nuts had not been applied and, as a result, there was a high likelihood that some of bay 70’s lashings would have come loose..

Since the ship’s loading computer was not fully utilised, warnings that the permissible load limits could be exceeded were not acknowledged or were ignored.

The investigation also identified a few safety issues not directly contributing to the accident..

As per the report, the ship crew may not have been able to maintain some of the twistlocks as they were in constant use and some of the twistlocks used were corroded and should have been discarded..

A key point that the report found was that “The potential commercial impact of addressing all the cargo stowage non-conformities contained in the plans produced ashore would have been high, and it is unreasonable to expect ships’ masters and C/Os to intervene.“..

Another important point was that the VGM for the containers in bay 70 exceeded the general industry error margin of 5% for 39 of the 107 containers loaded (36%) although the report also maintains that the differences between the declared and actual weights were unlikely to have been a major factor in the collapse..

 

Conclusion

Eerily, this report of MAIB seems to mirror the report released by Australian Transport Safety Bureau (ATSB) about the incident of the YM Efficiency in 2018..

The YM Efficiency lost around 81 containers overboard and 62 containers damaged due to strong gale force winds and very rough seas off Newcastle in Australia..

Similar to the MAIB, the ATSB found that the weights and distribution of containers in the affected bays were such that calculated forces exceeded allowable force limits as defined in the ship’s Cargo Securing Manual (CSM)..

The ATSB investigation also identified that the stowage arrangement was not checked for compliance with the CSM’s calculated lashing force limitations during the cargo planning process ashore..

The report also found that the officers did not use the ship’s loading computer system and its lashing calculation program to check if the stowage arrangement complied as they probably did not have an adequate understanding of the system..

container lashing - shipping and freight resource
Image : MAIB Report – Ever Smart

These incidents and reports bring into focus a few key issues and that is

  • the importance of proper and correct stowage planning by the shore planners
  • the expectation that the master and the ship’s crew monitor the status and condition of all lashing equipment on board
  • the containers used should be in sound structural condition
  • there should be no tolerance in the VGM weights and declared weights
  • the CSS Code and Cargo Securing Manual should always be followed
  • the personnel assigned with the task of cargo stowage and securing should be properly qualified, experienced, and have a sound practical knowledge of the application and content of the Cargo Securing Manual

*** End of Article ***

4 thoughts on “Importance of proper lashing of containers on board ships”

  1. Thank you for your minutest inputs as always.
    I have just retired after putting a decade in Auto MNC in Mumbai.
    Was conducting orientation sessions on Imports.
    Should have been part of your SHIPPING AND FREIGHT RESOURCE then.
    But knowledge is power.

    Reply
  2. It is important to note that mass in export and import means different things to different disciplines.
    The marketing people focus on net mass of cargo, as this is a determining factor in the import duty to be paid.
    Shipping lines only ask for all up cargo mass (gross mass of cargo) in order to release equipment within that mass range (design capacity of the equipment).
    The port terminal requires a verified gross mass of the cargo, plus equipment in order to plan stacks and never put too much weight on the containers below.
    The corner posts of container equipment are designed to carry a pile weight of 60 tons, which equals 240 tons max load on top of each container.
    Therefore, when planing a stack of containers to be stowed, on the ground or the vessel, all the containers above the bottom container may not exceed 240 tons total mass, or the bottom container may crumple under the burden.
    And here-in lies the recipe for getting the weights incorrect.
    Even today, despite the IMO regulations of 2014, implemented in July 2016, there exists this misguided application of weight in shipping cargo.

    Reply
  3. Up to ±1990, ships planners could evolve a stow plan to ensure all containers in a bay were of equal height. The bridge fitting lashing clamped the containers together at the corner posts.
    However, as more and more hi-cube containers came into use, it became impossible to plan a ships stow to ensure the tops of the container were of the same height in a bay. This created a significant safety risk.
    Important to note that the lashing rods used are limited in length as they become unwieldy over 3 meters.
    Only the container reachable from the deck or the lashing bridge are secured using the lashing road & bottle screws. Containers above the third tier rely on the twistlocks fitted to the underside of the container as it is lifted clear of the delivery trailer.

    Reply

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