The hand packing and emptying of containers is still common in many countries. The time required in packing or emptying a container depends on the kind, size and weight of the cargo, the means (manual or mechanical), and the number of persons doing the packing or emptying. Packing generally takes more time than emptying.

Unitized Load

Unitizing or unitization is the assembly and packing of a number of cargo, either the same or different items, into a standardized or compact unit for ease of handling by the mechanical equipment. The palletized cargo, container load and carload are examples of a unitized load.

The unitized load facilitates the loading, unloading and inventory of shipment, and improves the cargo security against theft, pilferage and damage.

Turn-Over Rate of Containers

In the CY/CY, CY/CFS and CFS/CY container services, the carrier allows the shipper or the consignee, as the case may be, to retain (hold) the container at their premises normally for 24-48 hours only, in order to maximize the turn-over rate of the container. An overtime use charge, known as demurrage, is collected on overstayed containers. In special cases, such as when the shipper or the consignee is doing a substantial amount of business with the carrier, some carriers may allow a longer time without charging demurrage.

Not all shippers have a container loading dock or raised bank with suitable dock plate at their premises, where the forklift and pallet truck can enter the container. The cargo is often manually or mechanically lifted from the ground onto the container that sits on the chassis (the bogie) or flatbed truck (the open truck). The inclining belt conveyor sometimes is used to move the cargo from the ground up to the container doors, and the roller conveyor is used to convey the cargo from the container doors to the inner section, particularly when packing a 40' container, which is deep.

In case the shipper's premises have a raised bank and the forklift is used, the forklift must have a lift mast that is non-rising and less than 7' 6" (i.e., less than 90 inches), in order to allow cargo to be forked into a standard dry cargo container.

In the case of a CY/CY or CY/CFS container service, the shipper has to arrange for the drayage of the empty container from the carrier's container terminal to the shipper's premises. The shipper must inspect the container to ensure it will adequately protect the cargo. In a dry cargo container, the doors, walls and ceiling demand the utmost attention.

The doors must be in good working condition and the door locking bars should secure and lock properly. The load may push against the container doors during a rough sea voyage. Even though the rating of a 20' container is 24,000 kgs., the doors cannot withstand that much pressure of solid load pushed against them during conveyance.

The walls and ceiling must be free from cracks or damage to prevent water and moisture from entering. There is a chance that a dry cargo container will be carried on deck since the cellular container ship carries about one-third of the containers on deck. The possible ingress of the sea water, rain and salt-laden moisture through a damaged container may ruin the cargo.

Always inspect the container before using it. If a container was contaminated (e.g. chemical spill) in prior use, then using the same container can be hazardous. Extra caution must be taken when packing food products in a dry cargo container. Some food products may absorb odor and moisture.

Never allow anyone to smoke inside a container. A carelessly discarded cigarette can cause a serious fire that may destroy the cargo and the ship, and may cause the loss of life.

In tropical areas, the air inside a dry cargo container is hot, humid and suffocating, especially inside a 40' container. To relieve discomfort when packing a container, it is necessary to use forced ventilation with an electric blower or fan. The air humidity is high, especially during the wet or rainy season. Forced ventilation can minimize humid air from being trapped inside a container, as the air may condense into liquid and damage the cargo when the container enters a subzero temperature area.

The weight of cargo must be distributed evenly within the container. As a rule of thumb, the center of gravity should not be above half the height of the container, and it should be within two feet from the center of container in the front-rear direction and within one foot in the sidewise (transverse) direction.

Cargoes like video monitors and glasswares have a stacking limit or the maximum stack. Otherwise, the compression from excess weight of overlaying packages may damage the goods underneath. For this reason, heavier packages should never be stowed above lighter packages. Liquids should never be stowed above non-liquids. Keep soft packages away from other packages or objects with protrusions or sharp corners, to prevent damage cause by movement at sea and on land (rail and truck).

A ship at sea may move in different directions simultaneously. Always apply dunnage (i.e., material used to separate and protect the cargo from damage during conveyance, for example, foam, mat and fiberboard) and/or cargo securements when necessary to prevent the cargo from crashing and cascading inside the container. Cascaded cargo may lie against the container doors, posing danger to any person who opens the doors.