In everyday life, freight is usually transported on the highway or by rail. For international freight transport, however, another type of freight plays a dominant role: sea freight remains by far the most important way of sending goods across the globe.
NOT ALL SEA FREIGHT IS THE SAME
Huge container ships with hundreds of large containers, next to which most ships look tiny: Anyone who thinks of “sea freight” will probably not be able to avoid this image. Yet the transportation of goods by sea freight is much more diverse.
Out and about on the open sea – and in inland waters
For example, a fundamental distinction must be made between transportation by sea and inland waterways. Due to the natural restrictions imposed on cargo ships by rivers and lakes, the transport performance of inland shipping in German freight transport is comparatively small: its share of total transport performance has stabilized at an average of around 6.7% since 2018.
As even large rivers are now regularly affected by drought and low water levels, the conditions for inland shipping are becoming more difficult. As a result, both domestic and cross-border traffic is trending downwards, as surveys commissioned by the Federal Office of Logistics and Mobility show.
Nevertheless, inland shipping should not be underestimated: it continues to be of great importance for internal EU trade. Here, the share of goods traffic is significantly higher than for Germany.
Forecasts: rising trend for sea freight
The global transportation of goods across the seas and oceans paints a different picture. This is because sea freight plays a prominent role here with a share of around 90 percent. The impact of the coronavirus pandemic on international supply chains has done little to change this.
According to forecasts by DHL Freight, the importance of sea freight could grow once again. An increase to over 250,000 trillion tonne-kilometres is possible by 2050 – from just over 60,000 trillion tonne-kilometres in 2010.
That sounds ambitious, but this forecast is based on the development of sea freight volumes from 2000 to 2020, among other things. Within two decades, the number of 20-foot standard containers (TEU) handled rose from 224 million to over 800 million.
WHY SEA FREIGHT IS SO IMPORTANT FOR THE TRANSPORTATION OF GOODS
There are good reasons for the high proportion of sea freight in international freight transportation. In a globalized economy, the ability to transport goods in large quantities over long distances is indispensable. Companies are willing to accept slower progress compared to other transport routes.
Sea freight transports simply everything
One of the main advantages of sea freight is that it can transport almost any type of goods. Bulk goods can be shipped well in various forms: both bulk goods such as coal, iron ore or grain and liquid cargo such as crude oil, oil products or gas can be shipped by sea.
At 1.9 billion tons, crude oil is the most important transport commodity in seaborne world trade, according to the German Shipbuilding and Ocean Industries Association (VSM) in its 2022/23 annual report. This corresponds to just over 16% of the total international trade volume. The VSM reports the following figures for other cargo in 2022:
| (in million tons) | |
| Container | 1.817 |
| Iron ore | 1.488 |
| Coal | 1.233 |
| Oil products | 1.030 |
| Gas | 530 |
| Cereals | 510 |
| Other bulk goods | 2.113 |
| Other goods | 1.312 |
| total | 11.983 |
For everything else, such as general cargo or transport units, there are containers with suitable capacity and properties. A basic distinction is made between general cargo (LCL = Less than Container Load) and a full container load (FCL = Full Container Load).
The right transport option for sea freight
There are not only differences in the type of cargo, but also in the variety of containers used for sea transportation. The options go far beyond the usual choice between the “classic” 20 and 40-foot containers. In fact, even the standard containers offer a range of variants:
- The most common dimensions, such as those used for goods on transport pallets, are 20, 40 or 45 feet, with the latter size being considered a high-cube container. On the North American market, HC containers are even available up to a size of 53 feet.
- For heavy goods, 20-foot containers are also available in a heavy-tested version. They can hold the same maximum total weight as the larger 40 or 45-foot containers.
- So-called inland containers (Pallet Wide/PW) are frequently used on the European market. They have a wider interior and can therefore hold two Euro pallets next to each other.
There are also numerous special sizes for height, length or width. The aim is to combine maximum loading space with optimum properties for onward transportation by road or rail.
Behind the general term “container” there is also a long series of variants that are intended for very specific tasks or situations:
| Container type | Characteristics |
| Refrigerated container
(Reefer) |
Refrigerated containers are used to transport sensitive goods such as foodstuffs. A distinction is made between two types:
Conair containers (also known as porthole containers) are double-walled and constructed with thermal insulation. They have two openings at the front, one above the other, through which they are connected to a ship-proof cargo refrigeration system. Integral containers have their own electrically operated cooling unit. This makes it possible to set the temperature of each individual container separately. This method has increasingly replaced Conair containers since 2000. |
| Tank container | Tank containers consist of a tank for liquid or gaseous cargo and a frame that holds this tank. Its dimensions correspond to a standard container size of 20 feet. |
| Dismountable sea containers | A not inconsiderable proportion of the world’s sea containers are handled without cargo because trade flows are not the same in all directions. However, empty containers are a relevant cost factor, as they still have to be loaded, transported and stored.
To save space and reduce costs, some containers can be folded or dismantled. In this way, several empty containers can be transported in just one parking space. |
The list could be extended to include a large number of other container types, which are basically special modifications of standard containers. These include, for example
- Bulk containers with openings in the ceiling and floor for easier loading and unloading,
- Flatrack containers, which only have end faces to accommodate large sea freight crates, for example,
- Open-top containers that are covered with a tarpaulin rather than a roof, or
- Containers with special opening devices, such as “double doors” with doors on both ends or full-side access containers where the entire side wall can be opened.
The success of sea freight in international trade is closely linked to the versatility of containers. A suitable solution can be found for every type of cargo to ensure safe and efficient transportation.
The right fleet for maritime trade
Appropriately adapted ship types are used on the seas, lakes and rivers to transport the many different types of goods. They are not only equipped for the respective waters, but also for the different types of freight.
Excluding ferries and passenger ships, fishing vessels, offshore vessels and other types of ships, 56,002 ships were in use worldwide for the transportation of goods by sea, according to VSM. Broken down by ship type, the following picture emerged for 2022:
| Ship type | Quantity |
| General cargo ships/other dry cargo ships | 16.755 |
| Bulk carriers | 13.134 |
| Oil/oil production tankers | 9.045 |
| Chemical/liquid tankers | 6.129 |
| Container ships | 5.682 |
| RoRo ships | 2.994 |
| Gas tanker | 2.263 |
Then there are the inland waterway fleets. These are characterized by their flexibility and can therefore transport a wide variety of goods on both large and small rivers. In addition to motor cargo vessels with a carrying capacity of up to 3,000 tons, motor tankers, push barges for dry cargo, tank push barges, barges for dry cargo and tank barges are also used.
In Germany alone, more than 2,000 of these ships sail the rivers. However, the number of German-owned merchant ships (regardless of the flag under which they sail) is somewhat lower. According to the German Shipowners’ Association (VDR), there were a total of 1,720 ships with a capacity of more than 100 gross register tons in 2022, in addition to 119 passenger ships.
The most important ship types were general cargo ships (628), container ships (618) and bulk carriers (219). Over the past ten years, however, the VDR has recorded a significant decline in the German merchant fleet. The number of German merchant ships has fallen by almost 40 percent during this period. By comparison, China’s merchant fleet has grown by around 140 percent.
LOLO or RORO?
Two different methods are used for loading and unloading cargo ships:
The most common method is the LoLo procedure. The abbreviation stands for Lift-on-Lift-off. The cargo is transported on or off board with the help of cranes – either the ship’s own or external ones.
With RoRo ships (roll-on roll-off), cargo handling works differently because it is driven onto the ship. These special ships have bow, side or stern hatches as well as ramps that allow access for cars, trucks, trains, standardized loading units or even swap bodies.
Handling times are shorter with this method, but RoRo ships are generally designed for very specific requirements. Their use therefore makes sense primarily on shorter sea routes and for special cargoes.
ConRo ships are a separate type of ship. They can transport both containers and RoRo freight.
WHAT’S NEXT FOR TRADE BY SEA FREIGHT
In a system as large and complex as international freight transport, it is difficult to make reliable statements. Since 2020, global or globally noticeable developments such as the coronavirus pandemic or the war in Ukraine have greatly increased the dynamics on the world market – and thus the volatility in maritime trade.
In addition, like all sectors of the economy, the transportation of goods by sea freight is affected by ongoing trends: Digitalization, automation and climate change require continuous adjustments.
IMO2023 regulation for cargo ships
The new regulation of the International Maritime Organization (IMO), which aims to reduceCO2 emissions in global maritime transport by 70 percent by 2050 (compared to 2008), has been in force since 1 January 2023. In this context, cargo ships will be certified in various efficiency classes.
These are determined using a Carbon Intensity Indicator (CII). Various options are available to shipping companies to meet the requirements of IMO2023. These range from selecting cheaper routes to reducing ship speed to save fuel and investing in more efficient ships.
Autonomous cargo ships as a serious alternative for the future?
Modern cargo ships already manage with a very small crew in relation to their size. GPS and the ship identification system AIS (Automatic Identification System) are the standard in maritime trade and at the same time important building blocks for shipping sea freight with autonomous ships in the future.
The advantages for shipping companies are obvious: personnel costs would be largely eliminated, and there would also be greater capacity on the ships, as there would no longer be rooms for accommodating the crew or storage rooms for provisions. In Norway, the technology company Kongsberg is already working on an autonomous container freighter with a length of 79 meters.
Rolls-Royce in the UK has had similar plans since 2013, albeit with a greater focus on possible areas of application. Unlike Kongsberg, Rolls-Royce wants to send its container freighters and tankers out to sea, for example. In the long term, the port facilities for loading and unloading are also to be automated.
Whether and when autonomous ships will become established for the transportation of sea freight is still questionable for the time being. The right infrastructural conditions are needed, for example to ensure safe shipping traffic on busy routes or to be able to implement automated handling in ports. In any case, the future of maritime trade remains exciting.
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