marine engineering

Home page||Ship employment ||


How to secure various commodities inside a container ?

Packing principles relating to cargo in containers

The principles below are applicable to cargo stowage in containers carried by sea, air, road or rail. This topic will be further discussed and illustrated in the relevant modules on the carriage of goods by sea, by air and by road and rail.

There are a number of basic principles applicable to the stowage of ALL cargo into containers. The maxim which summarises this set of principles is: safe container transport depends chiefly on a correct and immovable stow and an even weight distribution.



Either the container must be stowed tightly so that lateral and longitudinal movement of the cargo within it is impossible; or else the cargo must be effectively restrained.

Tight stowage :

This can be achieved by making the shape and the dimensions of the package an optimum module of the container or making the base of a unit load a module of the container.

Restraint

It is always necessary to restrain the cargo for one or more of the following reasons: To prevent. collapse of the stow while packing, unpacking, or during transit (e.g., rolls of linoleum on end);

To stop any movement during transit of part-loads or of single heavy items (e.g., large pieces of machinery) - the heavier the item the more damage it will do if allowed to move; and

To prevent the "face" of the stow collapsing and leaning against the container doors to fall out when the doors are opened at the final destination or for customs inspection.


Methods of securing cargo

The more common methods of securing cargo are:

Shoring - bars, struts and spars located in the cargo voids to keep the cargo pressed against the walls or other cargo. Lashing - ropes, wire, chains, strapping or netting secured to proper anchoring points and tensioned against the cargo.

Wedging : wooden distance pieces, pads of synthetic material, inflatable dunnage to fill voids in the cargo and keep it immobile against the container walls. Locking - cargo built up to give a three-dimensional brick wall effect.

Aids to good securing

There is no simple formula to follow when securing cargo. Each stow must be treated on its own merits - the type of cargo, the way it is stowed, the equipment available, or the permanent fittings in the container. But the following points should be borne in mind when applying restraint:

Always use the built-in securing points which are provided. For obvious reasons comply with the safe loading limitation on the securing points.

Any timber used - i.e., dunnage or filler pieces - should be dry. It may also have to comply with certain quarantine regulations in force.

If nails have to be used to secure cargo to a wooden floor, they should only penetrate about two-thirds the thickness of the floor to achieve adequate grip without total penetration. Holes must not be drilled in walls or floor. Never use nails in a reefer container (a refrigerated container).

Any shoring which presses against the container wall should have extra timber laid longitudinally between the wall and point of support to spread the weight over two or more side posts.

Useful filler pieces for wedging or preventing rubbing, sometimes called chafe, are old tyres, paper pads softened by soaking (macerated) or, for light packages, rolled-up cardboard.

Unless an identical stow is anticipated on the return journey (known as a closed circuit operation) it is best if, when the lashing equipment is chosen, it is considered re-usable.


How to restrain certain types of cargo

Top-heavy articles should be wedged, shored and lashed to prevent toppling. Heavy weights should be secured to stout ring-bolts (sited in the container floor and side walls) and/or be shored with timber. They should be chained or wired with bottle-screws (e.g., 1/2 in chain; 11/4 inch bottle-screws; three ton D shackles are adequate for lashing cargo up to 18 tons in weight).

Resilient loads can cause lashings to slacken - this may sometimes be overcome by introducing elasticity (e.g. rubber rope) into the lashing pattern.

No securing of pallets is necessary (provided the load is properly secured to the pallet) if the distance between pallets and container walls is 4in (100mm) or less. Pallets must not be allowed any longitudinal movement. If it is necessary to secure them, stow the pallets against the container walls and wedge wood blocks between the pallets. It may be necessary to insert sheets of board between the pallet loads to protect them against chafing and prevent bags, cartons; etc., interweaving and jamming the stowage.


Stowage precautions

In the majority of cases, there is a space (1" to 24") left between the face of the cargo and the container doors. It is important that the cargo does not collapse into this space. It can be prevented in a variety of ways, such as:

(a) Using suitably positioned lashing points with wire, rope, strapping, etc., woven across

(b) Inserting a simple wooden gate for the wider gaps and heavier cargo

(c) Providing filler pieces i.e., macerated (water-softened) paper pads, wood-wool pads made of fine shavings and used for packing, etc., for narrower gaps and lighter cargoes (like cartons of biscuits).

It is also important to ensure that the cargo does not fall out when the container doors are opened. This is particularly relevant to a container which has been completely packed (as with cartons or sacks). Although this can sometimes be achieved by interlocking tiers of packages, it is better to use the fixing points located in the door posts of general cargo container. Nylon strapping in polypropylene cord or wire (1/4" diameter or less) threaded through these points forms an effective barrier.


Other stowage precautions to be taken are:

Securing the goods in their packages and making the pack itself as full as possible so as to resist external pressures.

Making packages sufficiently rigid to withstand the weight imposed upon them when stacked to a minimum height of 8ft.

Making sure, if more than one type of cargo is stowed in a container, that they are compatible and cannot cause contamination or become contaminated.

Placing heavy items and liquids at the bottom, with light and dry items on the top. Within practical physical limitations of handling, the unit package should be as large as possible, since this can reduce costs by up to 20 percent and increase the efficiency in volume by up to 10 percent.

Where relevant, stowing should be carried out in a sequence which will permit rapid checking and storage operations during and after unloading. Should the consignment include cargo subject to customs pre-entry procedures, customs examination would be made easier and unloading avoided if the cargo were stowed at the end of the container by the door.

One should try to arrange for any unavoidable gap in the stowage to be along the centre line of the container and not at the sides. It is much easier and cheaper to restrain the shifting of cargo in this way.

A lighted cigarette end can destroy the contents of a container and even endanger the ship. When stowing a container the rule should therefore be NO SMOKING.


Load factors

Heavy loads must be assessed according to their shape, dimension and weight. However, as a guide, the weight or loads should be distributed over the container floor by means of suitable bearers or dunnage as follows:

(a) Width: distribution should be over the entire width of the container;

(b) Length: each ton weight of cargo should be spread over at least two floor members, which run transversely under the container floor at 1 foot centres (e.g., a 13 ton integral load would require to be distributed over 14 floor members i.e., 14 foot run of container floor).

The total load should be distributed as evenly as possible, but in certain circumstances the closed end half of the container can carry more than 65 per cent, or conversely the door end half more than 60 per cent, of the total load.




Other useful articles :
  1. Assigning loadlines marks

  2. Loadlines are marks punched into and painted on the sides of general cargo ships.The assigning of the vessels loadline and the issue of the Certificate is the responsibility of the Marine Authority of the country. .
    More .....

  3. Cargo ships Loaded Condition

  4. closely monitor the ship's condition during cargo operations to ensure that if a significant deviation from the agreed loading/unloading plan is detected all cargo and ballast operations must STOP..
    More .....

  5. Packing a container recommended method

  6. Packing a container should always be done on level plane either on the ground,on a railcar, or on a trailer. In the case of a trailer, care should be taken to ensure the trailer cannot tip whilst being packed especially if a forklift truck is being used. If necessary the trailer should be propped. Brakes should be securely applied and wheels choked.
    More .....

  7. Packing principles relating to cargo in containers

  8. Where relevant, stowing should be carried out in a sequence which will permit rapid checking and storage operations during and after unloading. Should the consignment include cargo subject to customs pre-entry procedures, customs examination would be made easier and unloading avoided if the cargo were stowed at the end of the container by the door.
    More .....

  9. Container Securing guidance

  10. Containers have very little strength in any direction other than vertically through the corner posts thus it is necessary to provide substantial support to the containers when they are on the ship. Stowage of containers is with their longer dimension fore and aft since the ship motion transmitted to cargo is greater in rolling than pitching and it is therefore prudent to limit any possible cargo movement within the container to the shorter transverse dimension.
    More .....

  11. Trim and stability booklet for cargo ships

  12. Contain either curves of form or hydrostatic tables and stability and trim characteristics for various conditions of loading .
    More .....

  13. Broken stowage? Cargo ships guideline

  14. The access shall be separate from the hatchway opening, and shall be by a stairway if possible. A fixed ladder, or a line of fixed rungs, shall have no point where they fill a reverse slope .
    More .....

  15. Ship type, design and facilities for cargo

  16. Cargo gear is designed for speed and flexibility for handling breakbulk, palletized, or container cargo. Various combinations of derricks, winches, and deck cranes are used for the handling of cargo. Cranes are fitted on many vessels to reduce manpower requirements. Some ships have special heavy-lift derricks that may serve one or more holds. Booms are rigged for either yard and stay (burton) or swinging-boom operation.
    More .....

  17. Cargo ships structural plans- how to use them

  18. Structural plans, sometimes called scantlings plans, show dimensions of the ships framing and plating. The midships section drawing, generally available for all ships
    More .....

Machinery system main info pages

Home page||Cooling ||Machinery||Services ||Valves ||Pumps ||Auxiliary Power ||Propeller shaft ||Steering gears ||Ship stabilizers||Refrigeration||Air conditioning ||Deck machinery||Fire protection||Ship employment ||


Home ||




General Cargo Ship.com provide information on cargo ships various machinery systems -handling procedures, on board safety measures and some basic knowledge of cargo ships that might be useful for people working on board and those who working in the terminal. For any remarks please Contact us


Copyright © 2010-2016 General Cargo Ship.com All rights reserved.
Terms and conditions of use
Read our privacy policy|| Home page||