Chaucer Freight - Tools - Cargo Care

How To Load Your Container

Homogeneous Cargo
If the load consists of homogeneous cargo (all the cargo has the same sizes) the complete volume of the container should be utilized. Different kinds of packaging methods exist such as cartons, boxes, bags, drums and barrels, rolls, liners for liquid bulk and small wooden crates. The container may have vacant cubic on completion of stuffing due to weight restrictions or otherwise and sensible securing is necessary on grounds of safety and cargo care.

Uniform Stowage
When uniform cargo is stowed into a container and free space is unavoidable, the cargo must be stowed in such a way that there is a gap in the middle of the stow as per diagram.

The gap, which can be fore and aft or athwart, must be chocked with wood or lashed with rope and if the cargo is fragile, nets or dunnage bags can be used.

Cartons & Packages
Important to follow any instructions printed on the cartons, e.g. particular side up for bottles of wine which require corks to remain immersed. To ensure stability in the stow and spread the weight as evenly as possible the "Bonded Block Stow" should be used.

Bagged Cargo
Bagged cargo tends to settle during transit causing pressure on side walls. Normal practice is to stow bags in interlocking stows. Bag on bag or building air chimneys within the stow may be necessary where extra ventilation is required. To avoid the risk of bags falling out of the container when the doors are opened, a brace or net is placed against the final row. Bags which are stowed and secured on pallets do not cause this problem and the cargo can be handled much faster.

Drums & Barrels
Drums and barrels in containers should always be stowed upright if possible. If the bung or closure is at one end, then it should be stowed with the bung uppermost. Barrels of earthenware etc should always be stowed upright.

Unless the drums or barrels are specially designed to "nest", there should be some form of soft dunnage or ply between each tier of drums. Dunnage should be laid sufficiently close to provide full support to the tier above

Rolling hoops, when pressed out of the side walls of the drums are particularly susceptible to rupture through chafe. In some instances it may be necessary to lay dunnage between individual drums to prevent rolling hoops from chafing one another. A second option is that each alternate row of drums may be lifted a few inches by carefully laid dunnage, allowing the rolling hoops to ride clear and reducing the effective diameter of each drum.

Ensure proper securing in way of the doorway with a fence, net or lashing.

Rolls
When rolls are stowed upright they should be packed closely together. Any empty spaces between the rolls should be filled in by sacks of sawdust, corrugated cardboard or similar soft dunnage. Secure the rolls by means of timber, nets or wedges.

When the rolls are stowed horizontally, the rolls which are nearest to the door should be secured by wedges or other similar devices as per diagram. Support the rolls evenly along their length on a flat surface particularly with cargo such as carpets.

Rolls of paper require paper clamps for careful handling.

Bulk Liquids
Wine, latex, printing ink and other non-hazardous liquids are often transported in strong synthetic "Flexi-Bags" in 20' GP containers. The bags must be braced at the door end of the container with a strong timber (or other material) bulkhead. Also make sure that the harness straps on the bags are secured tightly to the anchorage rings in the container. It is not only necessary to secure the load but also to make sure the pressure on the walls is not too high (if so the pressure must be distributed with planks or plates).

Bulk Solids
Bulk bags are used for a wide range of granular substances including malt, cocoa and coffee.

Hanging Garments
Specialist containers are available for shipping clothing garments. They are carried either on hanger rails or suspended from strings and significant traffic moves from the Far East, India, Sri Lanka and South Africa to Europe. Separate procedures issued by ICM cover all aspects of container preparation which are crucial for a successful out-turn. Failure to observe procedures can result in considerable claims for dry cleaning of garments which have dropped to the container floor.

Light Vehicles
Cars and similar light vehicles are commonly shipped in containers. Webbing or Spanish Windlass lashings are used as cross lashings. In the case of non-operating reefers this is via lashing eyes clipped into the T section flooring.

See AUTOMOBILES rules regarding petrol under the IMDG Code. Special car racks can also be fitted into containers to allow more cars to be carried.

Hazardous Cargo
All documentation must be completed.
Container must be properly placarded with an IMO danger label affixed to each of the outside walls of the container (front, door and the two sides).

IMO stowage segregation MUST be complied with at all times.

Safety & Securing
This section picks up important issues of safety that have been experienced with containerised cargo and to the related subject of cargo securing.

Overloading

There have been considerable incidents over the years of containers being loaded above their stipulated payload. In many cases the manifests declare cargo within payload limits when it is over. This is often exposed by the suspicions of a container handler or even an accident, resulting in a weigh-bridge check.

Overloading is something which no Steamship Line cannot entertain and in accepting cargo the following should be obtained or checked :

The number of pieces, size, weight and cubic of any commodity must be obtained.
The payload and cubic of the container selected/requested must be compared with the cargo particulars to establish whether a weight or cubic restriction applies. (A higher rated container may be appropriate).
Where a weight restriction applies the point loading of the cargo must also be checked in order that the tons per square meter loading limit is not breached. Cargoes such as metal ingots come into this category and timber is often required to spread the weight.

Road and Rail Limits

Apart from not overloading the container, the gross weight of the container (cargo plus container tare) must not breach the road or rail limits appropriate on all legs of the transit journey. This information can be obtained in DRS records or from the appropriate trade. The importance of observing these limits cannot be overstressed particularly where liability occurs in the case of an accident.

Shifting Cargo

The incidence of cargo moving inside a container during transit is considerable. It is usually because the cargo has not been secured properly or the packaging is defective. In particular we have recorded several cases where road vehicles have turned over due to cargo moving when negotiating a bend. The key issue is to secure cargo effectively to prevent the initial movement, because once loose the game is lost.

Securing & Reference to the International Maritime Organization (IMO)

Though containerized cargo is well protected, it is still subject to the constant movement and stress of transport. In heavy seas, the cargo is exposed to compressive forces due to pitching and rolling. These forces may increase the normal strain on lashings, struts and other securing devices as much as 100%. Effective securing of the load throughout the entire transport process is of absolute importance.

Reference books of note for detailed information include :

IMO Code of Safe Practice for Cargo Stowage and Securing. Vessel Cargo Securing Manuals - available onboard all merchant vessels and approved by the vessels Flag State Maritime Authority. Thomas' Stowage (ISBN 0 85174 625 X)

Securing Fundamentals

Contained in the IMO code above is a simple "Rule of Thumb to apply to securing loads aboard ship. (Refer to the code for more detailed information).

The total of the MSL values of the securing devices on each side of a unit of cargo (port as well as starboard) should equal the weight of the unit.

MSL or Maximum Securing Load is to securing devices as safe working load (SWL) is to lifting tackle. It is a term used to define the load capacity for a securing device.

Lashing and securing is a matter of know-how and experience and is normally performed either by terminal staff or specialized riggers. Essential information required when considering any piece of sizeable cargo is :

Mass in metric tons Principle dimensions (drawing if possible) Location of centre of gravity Bedding area and particular bedding precautions. Sometimes referred to as the "Footprint".

Lifting points or slinging positions Lifting gear if any accompanying the cargo, complete with test certificates Securing arrangements aboard ship Landside transport arrangements

When considering the shipboard stowage location of cargo items, acceleration forces should be borne in mind:

Lower accelerations forces occur in the mid-ship sections, lowest cell position under-deck and as close to the centerline as possible

Higher accelerations forces occur at ship's extremities, high on deck and in the outrigger slots by the ship's side.

When the lashing material is not specified (size of wire etc.) by the forwarder the lashing company will lash the cargo according to their own rules and experiences.

Not all cargo necessarily needs to be lashed. The best way of stowing cargo is often to stow one piece of cargo tight against the other cargo so they can support each other.

Securing Gear

A basic securing lashing may comprise the pieces listed below and its strength is that of the weakest link.

Wire of suitable strength. (MSL). Wire measured in diameter, parts, strands. Wire /bulldog clips to tie the wire. (Must be fitted correctly). Turnbuckles/ bottle-screws to tension the lashing Shackles to fasten the ends.

A securing lashing will always break at the weakest point or at the part with the lowest breaking strength so make sure you know the breaking strength of all lashing materials used. Protect the lashing material from additional weakening factors such as sharp edges, bending of bottle screws and shackles.

Where bottle-screws or turnbuckles are introduced the rating of this equipment must be equal to the maximum weight each lashing is expected to bear.

Securing in Containers

The cargo in containers needs to be stowed in such a way that the cargo can not move. The container itself is designed to permit tight, secure stowage of cargo.

These facilities include:

Floor of wood or plywood which permit blocks, stays and wedges to be anchored with nails or screws.
Internal walls, for the support of light cargo only.
Corner posts which are suitable for bracing to with timbers and lashing from via lugs .
Lashing lugs are located along top and bottom rails of the container at regular intervals.

An example of a typical 20 ft GP's lashing facilities are:

Sidewalls - Base - 5 lashing points rated at 2000kg Safe Working Load (SWL).
Sidewalls - Top - 5 lashing points rated at 500kg SWL.
Front end - Base - 1 lashing point rated at 500kg SWL.
Rear end - Door area - 5 lashing points rated at 500kg SWL.

Note:
The walls, doors and roof of the container are merely a protective shell which can not withstand concentrated stress. If the walls or ceiling are used for lashing purposes, make sure the stress on the walls or ceiling is evenly distributed.

Most types of cargo can be secured using the following materials :

Timber beams, struts, chocks, planks for shoring, bracing and relieving pressure.
Adjustable wooden battens, rods or strap belts for securing the load in sections, facilitating mechanical discharge.
Plywood and dunnage to separate several layers of cargo or to segregate different types of cargo into separate sections.
Foam-rubber cushions and air bags to reduce vibration and prevent the load from shifting.
Second hand tires or bags with paper-waste or sawdust to fill empty spaces, soften the impact and prevent shifting.
Nets to secure fragile goods.
Rope (hemp, manila, sisal etc.), wire, steel bands and terylene straps for lashing.
Nylon span sets
Bolt clips into T section flooring in Insulated containers
Bulkhead bars

Securing Calculations Aboard Ship

As per the previous diagram forces acting in a seaway are :

Rotational:- Rolling Pitching Sheering/Yawing

Linear movements:- Swaying Surging Heaving

Calculations to secure against the above forces follow a prescribed discipline and it is important to refer to this procedure when performing calculations. The recognized calculations are contained in "IMO Code of Safe Practice for Cargo Stowage and Securing".

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