FREIGHT CONTAINERS
The pattern of cargo reception and shipment has changed with the use of the freight container---container, box or LO/LO (lift on/lift off). The use of containers, which started more than 40 years ago, in intercontinental traffic, is now available in most seaports worldwide.
In the 1960's, many seaports either had inadequate container facility or none at all. Consequently, export shipments often relied on conventional (break-bulk) vessels. The cargoes were placed alongside a vessel for hoisting on board. The stevedores (longshoremen) were often employed to carry cargoes on and off the vessel. The loading and unloading of vessels consumed too much time, which caused dockside bottlenecks and delayed shipments. With the increased use of containers, the congestion was decentralized. The problem of congestion was transferred from the docks or piers to the container freight stations or terminals.
ISO Freight Containers
The acronym ISO stands for the International Organization for Standardization, with headquarters in Geneva, Switzerland. The ISO freight container refers to a container complying with the ISO container standards in existence at the time of its manufacture.
Container Classifications
Containers are available in configurations to take almost every kind of cargo and mode of transportation (ocean, air, road, and rail).
Containers for Intercontinental Use
In terms of the type of cargo for which the containers are mainly intended, they are classified as general cargo container and specific cargo container.
General Cargo Container
(1) General purpose (dry cargo) container
It is suitable for the widest varieties of cargo. It is fully enclosed and weatherproof, having rigid walls, roof and floor, with at least one of its walls, either end wall (end loading) or side wall (side loading), equipped with doors. |
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(2) Specific purpose container
It is used to facilitate the packing (loading) and emptying (unloading) of container other than by means of doors at one side of the container, and for other specific purposes like ventilation.
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• Closed ventilated container
It is used for the carriage of cargo, such as hides, that cannot stand excessive moisture. It is similar to the dry cargo container with specially designed natural or mechanical (forced) ventilation.
• Open top container
It is similar to the dry cargo container except that it has no rigid roof, but has a movable or removable cover (e.g. a cover made of canvas, plastic or reinforced plastic material) supported on movable or removable roof bows. The open top container is used for machinery, sheet glass, and other heavy, bulky or long objects.
• Platform (flat rack)
It does not have a superstructure, that is, rigid side walls and load-carrying structures. The term load refers to static/dynamic form of load (not cargo load) or forces arising out of the lifting, handling, securement and transporting of container. It is equipped with top and bottom corner fittings.
• Platform based containers open sided |
Specific Cargo container
(1) Thermal container (reefer)
It has insulated walls, doors, roof, and floor, which limit the range of temperature loss or gain. It is used for perishable goods like meat, fruits and vegetables.
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• Insulated container
It does not use any device for cooling and/or heating.
• Refrigerated container (with expendable refrigerant)
It uses dry ice or liquefied gases. It does not require external power supply or fuel supply.
• Mechanically refrigerated container
It uses a refrigerating appliance, that is, the mechanical compressor or absorption unit.
• Heated container
It uses the heater, that is, a heat-producing appliance.
• Refrigerated and heated container
It uses the refrigerating appliance (mechanical or expendable refrigerant) and heater. |
(2) Tank container
It is used for the carriage of bulk gases and liquids like chemicals
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(3) Dry bulk container
It is used for the carriage of dry solids in bulk without packaging, such as grains and dry chemicals. It consists of a cargo-carrying structurre firmly secured within the intercontinental framework.
(4) Named cargo types
It consists of various types of containers, such as automobile (car) containers and livestock (cattle and poultry) containers.
Container Dimensions and Capacity
Containers intended for Intercontinental use have external nominal dimensions of:
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All above dimensions have permissible tolerances
The 20 feet (20') and 40 feet (40') containers are very popular in ocean freight. The 8.5 feet (8.5') high container---8 feet 6 inches (8' 6") high container---is often referred to as standard container.
The demand for the high cube container---hicube---is increasing. The popular high cube container has a normal height of 9.5 feet (9.5' or 9' 6").
There are half height containers (4.25' or 4' 3" high) designed for heavy loads such as steel rods and ingots, which absorb the weight limit in half the normal space.
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The most widely used type of container is the general purpose (dry cargo) container having a nominal length and height of 20' x 8.5', 40' x 8.5', and 40' x 9.5'. The container capacity is the total cube a container can accommodate. The term cube often refers to the cubic measurement of cargo. The capacity (i.e., the internal volume) is determined by multiplying the internal dimensions, that is, the product of internal length, width and height. The capacity may vary among containers of the same length and height.
The Marking and Identification of Containers
The rating, tare mass and payload of a container is marked on its wall, usually on the end (rear) door in the case of an end-loading dry cargo container.
Each container has an identification code or container number---a combination of the 4-letter characters that identify the owner (the operator of container) and the 7-numeric characters that identify the container. The container number can be found on the outer and inner side walls.
The container number is entered on the bill of lading to facilitate the identification and tracking of the container and the cargo.
Table and Diagram:
Dimension of General Purpose Containers
Dimensions of General Purpose Containers
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Containerized Shipments
The use of containers in export shipments makes the transport and handling easier and faster. The crane and gantry are commonly used in handling containers. The forklift is also used at the docks and container terminals to move the 20' and shorter dry cargo containers, which are equipped with fork pockets or tine pockets.
The ports worldwide handle over 100 million TEUs annually. The unit TEU (twenty-foot equivalent unit) is used to express the relative number of containers based on the equivalent length of a 20' container. For example, 100 containers of 20' is 100 TEUs, while 100 containers of 40' is 200 TEUs.
The container ships used in the international traffic are designed with the cells (compartments with cell guides) resembling a honeycomb wherein the containers are placed, thus named cellular container ships.
The ships are bigger and faster nowadays, especially those used in the deep-sea voyage (long haul). Those rated below 20 knots are common in the short-sea voyage (short haul). The knot is a unit of ship's speed, being one nautical mile per hour. One nautical mile is 1.852 kilometers. A ship that steams at 20 knots is moving at a speed of about 37 kilometers per hour.
Some cellular container ships in the 20 to 23 knot range can accommodate 2,000 to 3,000 TEUs. Some rated 24 knots have a carrying capacity of 4,000 to 4,900 TEUs and load of 56,000 to 75,000 metric tons. The length of the vessel can be about 900' (275 meters) and the beam---the widest part of a ship---can be about 125' (38 meters). The size of vessel is huge compare to a standard football field having a goal line of 300' (91.44 meters) and an end line of 160' (48.77 meters).
Convenience of Containers in Multimodal Transport and Transhipment
Containers are designed to facilitate the carriage of goods without intermediate reloading. They are fitted with devices permitting their ready handling, particularly in the multimodal transport and transshipment .
RO/RO Vessals
Besides the full container ship, the RO/RO (roll on/roll off) vessel amd the LASH are other systems of water transport used in international trade
RO/RO (Role ON/Role Off) Vessels
The RO/RO vessel (RO/RO or RORO) derived from the traditional car ferry, where motor vehicles are driven on and off by their drivers. RO/RO is popular within the European trade routes. It is also used in other trade routes like the U.S.A.-Central America route and Europe-West Africa route.
The RO/RO is equipped with ramp(s) that makes loading and unloading from the side and/or bow (front of vessel) and/or stern (rear of vessel) possible. Some modern RO/ROs are designed as a trailer/break-bulk/container carrier suitable for the deep-sea voyage (long haul), making loading and unloading of containers from the top, like a full container ship, possible using the crane. The type of cargo that can be carried on a RO/RO is flexible, including large objects.
The full RO/RO has low stowage factors, as a result of wasted space around the underside of the trailers and other motor vehicles. Therefore, the full RO/RO is not ideal for deep-sea trade. The low stowage factors, however, are compensated for by the quickness of the "turn around' time in ports in the short-sea voyage (short haul).
In general, the capital cost for a full RO/RO is lower than the full container ship or the lash. When the cargo availability is insufficient in a port in the short-sea trade, investment in sophisticated container handling installations can be uneconomical. Therefore, the full RO/RO offers a solution to short-sea transport needs. A large area of land for parking trailers and other motor vehicles is necessary while they await loading.
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