How to Select the Right Cargo Container

31 May 2021 • 13 min read

byEditorial Team

Choose the right cargo container for your ocean freight and optimise your international logistics costs.

Six decades since its inception, container shipping today accounts for 60% of international maritime trade by value, or $12 trillion (as of 2017). It is an easy, safe and cost-effective solution for exporters and importers.

While it has simplified international trade, container shipping itself has become more complex to accommodate a wide range of goods being shipped across the world. As a result, exporters often struggle to find the right container for their goods. One reason for this is their overdependence on freight forwarders and customs house agents – intermediaries who specialise in making decisions for their clients. But an exporter who makes informed choices about his shipment on the basis of personal knowledge worries less about things going wrong. Choosing the correct container is just one of these important decisions.

This blog aims to familiarise exporters with the world of containers and container shipping, and hopefully help them make the right choices. It will tackle the following subjects:

What can go wrong by picking the wrong container
Types of containers used in container shipping
Standard container sizes
Freight weight, freight volume and how to calculate them
Load capacity and how to calculate it
Everything else to watch out for.

The Wrong Container Can Lead to a Sea of Problems

Exporters risk damage to their cargo if the container is not the right fit or the right type. A lot can go wrong, such as:

Containers being dropped during handling due to overweight or unevenly distributed cargo
Leaks, fires, temperature damage due to improper packing, stowage and miss-declaration of cargo. Improper packing and/or stowage accounts for 95% of cargo damage
Cargo contamination from container floor/pallet preservatives, wet surfaces, other cargo (for shared containers)
Cargo damage due to insect and vermin infestation.

Types of Containers Used in Container Shipping

First, it is important to pick the right container type for your cargo. You have six options to choose from:

Dry storage container: Made of aluminium or steel, it is used to ship dry freight. The most popular variety is either 20 feet or 40 feet long. It has doors on one side. Up to eight of these containers can be stacked one on top of the other
Flat rack container: With collapsible sides that fold, it is ideal for transporting cars and boats
Open side container: Can be opened completely on the side, allowing wider loading. Popular option for vegetables such as potatoes, onions
Open top container: Has no roof and is ideal for odd-sized goods such as machinery and logs
Refrigerated container: Also called a reefer, it is a cooling container with a generator and is used to transport food, flowers and pharmaceutical goods. Newer versions come with a carbon dioxide control system that keeps ripening food fresh
Tank: A cylindrical container designed to retain liquids, gases and powders. Carries both hazardous (oils, chemicals, fuels) and non-hazardous (wines, spirits, juices) products. There are various types of tank containers – baffle, lined, heated, refrigerated and gas tanks.

Containers are also classified on the basis of whether they are fully used or shared:

Full Container Load (FCL): This means a container is used for a single shipment. It is suitable for big businesses transporting goods in bulk. The advantage of an FCL container is that once it is loaded and sealed at the port of origin, it is opened only at the port of destination. This ensures faster delivery and more security for the goods being shipped.
Less-than-Container Load (LCL): This is suitable for transporting cargo in moderate volumes. Multiple exporters can share one container. It works out cheaper but delivery might be slower.

Standardised Containers: One Size Doesn’t Fit All

When the first containers were built in the 1950s, they were 33-35 feet in length. In 1961, the International Organisation for Standardization introduced standard-sized containers to make them compatible with different modes of transport (rail, sea and road). The most widely used are the 20-foot and 40-foot containers:

20-foot container: Also called the Twenty-foot Equivalent Unit (TEU). Designed to carry heavy rather than voluminous cargo (minerals, paper, metals and machinery).
40-foot container: Also called 2 TEU. Designed to carry voluminous rather than heavy cargo (furniture, cotton, tobacco, steel pipes).
40-foot high cube container: The same as a 40-foot container but with an additional height of one foot.

How to Calculate Freight Weight and Freight Volume

After selecting the right container type, the next step is to calculate freight weight and freight volume. The first is easy. Calculate the weight in kilograms or tons. As for freight volume, it is measured in cubic meter (CBM) and the formula is fairly simple:

‍(Length x Width x Height) x Quantity

So, if your cargo comprises identical boxes, it is the length x width x height of each box multiplied by the number of boxes. If the boxes are of different sizes, repeat the formula for each size and add up the volumes.

Note: To calculate the CBM of cylindrical packages such as a rolled carpet, exporters must check if the ship squares the circle, which means the diameter becomes the width and height. If not, use the formula Pi x 2 (squared) x Height where pi is the ratio of the circumference to the diameter of a circle.

There are numerous CBM calculators available online, that do the math for you if you fill in the required number fields.

How to Determine Load Capacity‍

Knowing your freight volume is necessary for figuring out how much space your cargo will occupy in a standard sized container. Here, it is important to understand that a container cannot be filled to its maximum capacity, and that its actual capacity is a little over 80% of its maximum capacity.

(HC = high cube)

* Measurements based on ideal conditions, could vary from operator to operator

How to Pay for Your Container

For FCL containers, you usually pay what is called a commodity box rate (CBR). The Business Dictionary defines CBR as “freight rate classified by commodity and quoted per container”.

For LCL containers, freight is charged on the basis of volume or CBM, provided the freight weight does not exceed one ton. For cargo weighing more than one ton, freight is charged on the basis of CBM or weight, whichever is higher.

A Few Things to Keep in Mind

That takes care of the heavy lifting. All that’s left now is to book the right container. But wait. There are still a few minor things to watch out for:

Different shipping lines have their own weight limits. Be sure to check with them beforehand
Check what you are allowed to export. For instance, some destination countries might have banned certain goods from entering their soil
Pack and stow your cargo safely to avoid the problems listed above. Also make sure you declare your cargo accurately. You may be liable for any lapses
Get yourself a good freight forwarder and customs house agent. As professionals familiar with everyone in the shipping process, they can offer expert advice, get you the best offers and troubleshoot if glitches come up