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A Review of Maritime Operations

Maritime transportation is the least costly mode of transportation and, as such, it plays a major role in the world trade expansions. This chapter provides an overview of the importance of maritime transportation in current global economic conditions (section 1.1) and introduces various types of loads and ships in maritime transportation (section 1.2). Containerization, a revolutionary concept in maritime transportation, is reviewed in section 1.3, followed by a brief introduction to handling equipment in seaports in section 1.4. A short overview of the main optimization problems faced in maritime operations is presented in section 1.5 and the chapter is concluded in section 1.6.

1.1. Maritime transportation

Nowadays, supply chain networks are increasingly complex, and the logistics associated with them present more challenges than ever, mainly due to the fast trend of globalization. The ever-increasing importance of sustainable development strongly depends on the development of transportation infrastructures. Although there is no explicit hint to transportation in the United Nations' sustainable development goals [UNI 18], it is considered as the most critical factor to reach its goals and targets.

As an essential tool, maritime transportation lies at the heart of globalization and the international trade boom. This mode of transportation revolutionized industries by enabling almost any company, regardless of its size and location, to export its products all around the world. Maritime transportation, mainly ocean and deep sea, is considered as the corridor of global international trade. Conceptually, any goods, other than time- or content-sensitive ones, can be moved by sea. Although maritime transportation is one of the slowest modes of transportation, due to its higher transported volumes and lower operational costs, it is a widely used intercontinental transportation mode for all types of loads, from heavy loads such as ores, grains, coal and coke, to liquid loads such as crude oil and liquefied natural gas, and to final products such as cars, digital instruments and household appliances. If the delivery time is not an important matter, larger, odd-shaped products including engines and propellers may be moved via this mode, as well. Many types of cargo can only be transported by sea since, due to either their size or shape, there is no other physically or economically viable option.

According to Yuan [YUA 16], almost 85% of total international trade is transported by sea. More specifically, for the EU member states, 75% of their imports and exports depend on maritime transport [EUR 15]. It is the leading mode of long-distance transportation in the world, with a transported volume of over 10.6 billion tons in early 2017, almost twice that of 1995. Although this increase represents an annual average growth of almost 3.5% in the past 22 years, a similar and steady annual growth is expected in the near future, approximately 3.2% during 2017 to 2022 to reach 12.5 billion tons of transportation by 2022 [UNC 17].

The fast increase in the worldwide fleet size and fleet capacity, consisting now of more than 93,000 commercial ships with a total tonnage of 1.86 billion deadweight tons (DWT), has been a key factor in globalization and lies at the center of global support supply chains. Massive transportation capacity, as well as low carrying costs, has led most countries to increase the throughput of their maritime transportation, especially developing countries, which by 2016 accounted for around 59 percent of loaded (i.e. exports) and 64 percent of unloaded (i.e. imports) total volumes of international maritime trade [UNC 17].

Although maritime transportation has almost the longest transit time and needs the highest level of capital investments, it is known as the least expensive and safest mode of long-distance transportation. Additionally, while the size and weight are an important issue for air transportation, this is not the case for maritime transportation. Although ships usually need to travel a longer distance compared with other modes of transportation, maritime transportation is still the mode with the least CO2 emissions. Nevertheless, the maritime industry itself is seriously affected by the impacts of climate change, such as rising sea levels and more extreme weather [VIL 15].

To compare different modes of transportation, we selected a very common route between Shanghai in China (busiest container terminal in the world), and Rotterdam in the Netherlands (busiest container terminal in Europe). To have a fair comparison, we estimated that one twenty-foot equivalent unit (TEU) container, a common unit to count carrying capacity by train, trucks and ships, is able to carry 20 tons of load, on average. Table 1.1 shows an estimation of the average transportation costs for one TEU by a ship or a train and 20 tons of load by plane or trucks. The data presented in this table have been gathered through surveying duration, distance and cost from [SEA 18, CAR 18, UNC 17], and emission rates from [HIL 18]. The emission rate is counted by grams of CO2 per ton-kilometer (g/tkm). Although maritime transportation is the longest mode of transportation, it is the cheapest and greenest mode of transportation, as well. It is noteworthy that air cargo produces almost 100 times more CO2 than maritime transportation.

Table 1.1. Comparison between the four main modes of transportation in a route between Shanghai and Rotterdam

1.2. Types of ships and cargo

Bulk cargo is mainly divided into four categories, dry bulk cargo (e.g. grains, sand, coal, ores, etc.), liquid cargo (e.g. crude oil, LNG, liquid fuels, chemicals, vegetable oil, etc.), other main bulk commodities or break bulk (e.g. goods in sacks, cartons, crates, wood, paper, steel, autos), and containers. These four main cargo categories have a certain portion of the maritime transportation market, depicted in Figure 1.1, based on the data from [UNC 17] for the year 2016.

Figure 1.1. Market share of cargos transported by sea in 2016

There are currently three main routes in the world for maritime container transportations, namely from Asia to Europe, from Asia to North America and from Europe to North America [GEL 13]. Main routes for oil and gas include the Persian Gulf to Asia, Europe and North America. For the dry bulk cargo (mainly iron ore and coal), the main routes are from Latin America to Europe and to the Far East, and from Australia to the Far East. Other commodities are transported all over the world, but mainly from the Far East to Europe and to North America. Cargo flows are set to expand across all segments, with containerized and dry bulk cargo trades recording the fastest growth.

Beside leisure, educational and passenger ships, most of the larger ships are used for merchant purposes. The smallest portion of the world fleet belongs to the Ferries and passenger ships with less than 0.3% of the total tonnage.

Huge tanker ships transport fluids such as crude oil, petroleum products, liquefied petroleum gas (LPG), liquefied natural gas (LNG) and chemicals, also vegetable oils, wine and other foods. Currently, tankers have more than 500 million tones of DWT accounting for 28.7% of the world commercial fleet deadweight [UNC 17]. However, the largest portion of the commercial fleet is dedicated to the dry bulk cargo ship with almost 800 million tones of DWT, which represents 42.8% of the world fleet deadweight. Break-bulk cargo ships represent just under 4% of the world fleet deadweight. A special version of the break bulk cargo ships, known as roll-on/roll-off (RORO), are used to carry wheeled cargo such as automobiles, trailers or railway carriages. RORO ships have built-in ramps that allow the cargo to be efficiently "rolled on" and "rolled off "from the ship when in port. Perishable goods such as fruits, meat, fish, vegetables and dairy products, which need temperature-controlled transportation, are transported in refrigerated ships (reefers).

The most preferred mode of transportation for containers is the containerships, which, with 245 million tons of DWT, account for 13.2% of the world fleet DWT. They are, typically, operated on fixed maritime routes that include various container terminals worldwide. For the deep-sea containerships with a general capacity of several thousand TEUs, the deck is subdivided into several holds, each of which can carry between 200 to 400 containers. Containers may be stacked on the deck or below deck. Deep sea containerships are mainly used for interlinking Europe, North America, South America, the Far East and the Middle East. For the shorter distances between the...