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On Deck Loading & Securing of 20feet Containers

In the world of seaborne trade, the continuous growth of container ships allows most goods now to carry in a cost-effective way. However, to achieve this, it needs some careful consideration while planning and stowing different types and sizes of containers. An evil stowage plan unable to accommodate maximum boxes due to weight and size restrictions. Also, ship stability requirements may not be able to meet. Therefore, once received shipment information, a prudent terminal planner takes into account all limitations that may present. He is also aware of the unique requirement for each ship type. For example, in most ships, 20feet containers loaded on deck must be spaced apart to leave room for lashing each box on the fore and aft ends.



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Closed loading is not allowed unless specifically mentioned in the cargo securing manual or loading manual. In such a case, lashing can be taken only at one end of the container. Also when loading a mixed stow on deck, i.e., 20’ boxes amidst 40’ boxes in the same Bay, care must be taken when planning the stow. If the 20’ containers are blocked, is closed off by 40’ containers on either side, it will not be possible to take lashing at the inner ends of the 20’ containers. (so-called “sandwich stow”)

Lashing pattern of outboard containers
Lashing pattern of outboard containers

If such lashing has been taken before loading the 40’ containers on either side, then the problem will occur when checking lashings at sea and when discharging the 20’ containers as the inner end lashings will be inaccessible.

Empty Containers Use of Wire Slings : Wire slings may be used for the lifting of empty containers only – they shall not be used for loaded containers.

Stowaways in empty containers : Personnel must always be aware of the use of empty containers by stowaways. Every effort is to be made to ensure all empty containers are checked and sealed before loading. The details of action taken to prevent stowaways boarding in empty containers must be recorded in the deck logbook.

Damaged Empties : Whenever damaged empty containers are to be loaded, care must be taken to ensure that the damage details are agreed with the Stevedore, Charterers Agent, and recorded on the cargo paperwork.

Securing Requirement
  1. When containers are carried on deck, the ship is required to be approved for that purpose and the boxes themselves are secured with twist locks 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.

  2. When containers are carried under the deck, the boxes are slotted into cells 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, it may be necessary to over- stow the 20’ containers with 40’ containers. The Cargo Securing Manual should be consulted before loading.

  3. containers stowed below deck
    Containers stowed below deck

  4. 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 to avoid delays and non-compliance with cargo securing requirements.

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

  6. Ships lashing gear must be well cared for, and crew must always be vigilant to avoid loss of lashing material. The loss is mainly due to pilferage, damage, or being left on the quay, and Twist-locks remaining on discharged containers are carried away to the yard.


  7. Corner fittings located at all eight corners of the container are called corner castings. They are used to handle the container. Lifting gear, such as container gantries and cranes, is attached to the corner castings of the containers to lift them. The corner castings are used in conjunction with twist locks to secure containers when traveling on-road vehicles or stack and fasten them securely to the deck of an ocean-going vessel. The twist locks are placed in the corner castings and engage with the corner castings (on the floor) of the next container.




Related topics:

2 in 1 container operation in cargo hold

How to load 45 feet containers



Container handling more info pages:

  1. Definition of various containers in containership
    The exterior dimensions of all containers conforming to ISO standards are 20 feet long x 8 feet wide x 8 feet 6 inches high or 9 feet 6 inches high for high cube containers. Some of the most commonly used types are:Read more......


  2. Dimensions of various containers
  3. Containers are standardized cargo units. They are manufactured in a large variety of sizes and types, each designed to meet specific cargo and transportation requirements. Their length is usually 20 or 40 feet, although longer containers are used, principally in the US trade; these containers are 45, 48 and 53 feet long.
    Read more......

  4. Containership advantages : In principle they are boxes or containers within a box. These boxes or containers have dimensions of 2.60 x 2.45 m with lengths of 6.10, 9.15 and 12.20 m. Containers are made in steel, aluminium or GRP. They are also of refrigerated design, thus advantageous for long voyages between Australia or New Zealand and the UK. Read more......


  5. Containership cargo stowage and planning : When considering acceptability of a container cargo stowage plan, the following procedures / guidelines concerning cargo stowage shall be taken into account: Stacking Weights Restrictions, Lashing strength calculation, Dangerous goods stowage and segregation, Reefer Container Stowage , Out of Gauge Container Stowage , ....Read more......


  6. DG cargo handling - IMDG code guideline :The general provisions for segregation between the various classes of dangerous goods are shown in "Segregation table" (IMDG Code Chapter 7.2.1.16). In addition to the general provisions, there may be a need to segregate a particular substance, material or article from other goods which could contribute to its hazard. Read more......


  7. How to avoid irregular stowage of containers ? Stowage plan must be checked for any irregular stowage like those mentioned here : Stacking Weights, Lashing Strength, Special Container Stowage, Over-stow of Containers, Dangerous Cargo Stowage & Segregation, 20 or 40 or 45 feet Compulsory Stowage Locations, Hatch Cover Clearance (High cube containers Under Deck ), Out of Gauge Container Stowage etc.Read more......

  8. Flat Rack Container
    Fig :Flat Rack Container showing
    corner castings at each corner

  9. Measures against lashing failure : 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 vessels classification society.Read more......


  10. Reefer container stowage guideline : Reefer containers proposed for stowage must be accompanied by a reefer manifest. This reefer manifest should contain information regarding Container No., Stow position, Commodity, Temperature and Ventilation status. Read more......


  11. Care of Reefer container during sea passage :Reefer containers require special care after they are loaded on board ship. These containers need to be supplied with power, monitored closely for proper function and repaired as required in case of malfunction. Read more......


  12. Container ships procedures for securing for sea :All movable items on deck, inside accommodation and in E/R spaces, including under-deck passages and steering flat are firmly secured. Any unsecured items, in heavy weather, risk not only being damaged themselves, but could also pose a danger to vessel safety by violent contact with sensitive equipment or fittings.Read more......


  13. Deployment and monitoring of moorings and safety of crew :The Company’s Risk Assessment procedure shall be utilized to ensure that during all anticipated mooring arrangements and equipment use, the safety of crew is ensured. Read more......


  14. Cargo securing procedure for container ship :Securing equipment will vary depending on the type of ship but is likely to include; Twistlocks Lashing bars Turnbuckles Extension hooks Stacking cones (single and double) Twist Stackers Lashing D rings Shoes/Sockets for base twistlocks ...Read more......


  15. Containership operation -Check items upon completion of repair works : As the nature of container ship operation, it’s tread to be lack of stability, due to Top Heavy Load, the Master shall always take special attention for her stability. Also the Master should remind factors to cause reducing stability more such as Alternating course with Big angle of Rudder, Towing by tugs at the scene of Berthing / Un-berthing, etc. Read more......


  16. Containership operation -Cargo ventilation requirement : Cargo holds of container ships are fitted with two basic types of ventilation systems, namely natural and mechanical. Mechanical ventilation could be of either the supply or the exhaust type. Read more......


  17. Containership operation -How to avoid wet damage ? :Water entered into vessel cargo holds may cause wet damage to the cargo inside containers especially stowed on the bottom, unless the bilge water is drained in a proper and swift manner. Read more......




Other info pages !

Basic guideline for Container Ship Operation
Tanker vessel safety guideline Check items in oil tankers operation
Questions from user and feedback Read our knowledgebase
Cargo care at sea Precautions to be taken
Reefer cargo handling Troubleshoot and countermeasures
DG cargo handling Procedures & Guidelines
Cargo securing Check items prior departure port
Safe navigation Various factors affecting ships navigation at sea
Hull strength & stability Prior loading how to ensure hull strength & stability of ship
stevedores injury How to prevent injury onboard
Environmental issues How to prevent marine pollution
Safety in engine room Standard procedures
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