Global Shipping is the conduit of world trade and a global economic engine. The significance of the shipping industry is huge as it is a key element in the international economic development. With over 50,000 of all types of merchant ships trading internationally and transporting every kind of cargo, the world fleet is dominated by dry bulk carriers, oil tankers and container ships.
Overview of the main merchant ships types and sizes
Bulk Carrier Vessels:
As their name suggests, these vessels primarily carry bulk cargoes such as coal, iron ore, grains, cement, and minerals. In 2017 they comprise 43.2 % of the world’s merchant fleet (in terms of percentage of dead-weight tonnage). In contrast to the general cargo vessels, which can load several different cargoes, bulk carriers are characterized by the homogeneity of the cargo they carry. Here are the different categories of bulk carriers:
Small bulkers with a deadweight of up to about 10,000 tonnes, they are mainly used in short sea shipping trades. These small ships are mostly used for the transportation of limited quantities of general cargo rather than as typical bulk carriers.
Handysize bulkers’ deadweight ranges from about 15,000 tonnes to about 30,000 tonnes and they can be equipped with 5 cargo holds and 4 cranes, while the smaller Handysize vessels may contain 4 cargo holds as well. These vessels due to their shallower draught and smaller size can operate in most ports and terminals
around the world.
Handymax bulkers have a deadweight from about 35,000 tonnes to about 50,000 tonnes and they are equipped with 5 cargo holds. These vessels are suitable for small ports with length and draught restrictions, or ports that don’t have the necessary transloading facilities.
Supramax bulkers, which in the recent years have been replacing Handymaxes, have a deadweight from about 50,000 tonnes to about 60,000 tonnes. Like Handymaxes, Supramax bulkers also contain 5 cargo holds. A newer design which can be considered as an upgrade of the Supramaxes is equipped with eco engines and have a deadweight ranging from 62,000 – 65,000 DWT, are known as ultramaxes.
Panamax bulkers are those vessels with a deadweight of between 70,000 and 80,000 tonnes capable of passing through the Panama Canal locks. Older Panamaxes in the market (referring to those built before 2000) commonly have a deadweight range between 60,000 and 70,000 tonnes. Panamaxes normally can have 7 cargo holds and their name and dimension characteristics were established according to the maximum allowable dimensions set by the Panama Canal Authority. Due to the recent expansion of the Suez Canal, the new larger designs that appeared are known as Post-Panamax bulkers and their size range is from 90,000 tonnes to about 110,000 tonnes DWT.
Capesize vessels are large-sized bulk-carriers mainly have a deadweight of between 160,000 tonnes and 210,000 tonnes can have 9 cargo holds. These vessels are suitable to serve only the large ports with deep water terminals in the world. Older smaller Capesize versions are known as Mini-Capes where designed to have a deadweight between about 110,000 to about 160,000 tonnes but their use is very limited nowadays. Larger designs of Capesize vessels that have a 400,000 tonnes DWT are mainly used for huge loads of iron ore and they belong under the category of Ultra Large Ore Carriers.
Tankers are primarily used for bulk transporting of crude oil, finished petroleum products, liquefied natural gas (LNG), chemicals, and other liquids like water.
Classification of Tankers by DWT Size:
Small Tankers / General Purpose tankers: They are used to load refined products and their size is between 10,000 MT (metric tonnes) and 25,000 MT deadweight.
Handysize tankers (Intermediate): Used to load refined products and their deadweight is between 25,000 MT and 35,000 MT.
MR 1 (Medium Range 1) tankers: Used to load refined products and their size is between 35,000 MT and 45,000 MT deadweight
MR 2 (Medium Range 2) tankers: Used to load refined products and their size is between 45,000 MT and 55,000 MT deadweight
LR1 (Long Range 1) tankers / Panamax: Panamax are mid-sized tankers that are capable of passing through the lock chambers of the Panama Canal. Their deadweight tonnage ranges between 50,000 to 80,000. They are used to load both refined products and crude oil. More strictly and under the average freight rate
assessment, the LR 1 ranges between 45,000 DWT to 79,999 DWT.
LR2 (Long Range 2) / Aframax / Suezmax: LR2 tankers range from 80,000 DWT to 159,999 DWT according to the average freight rate assessment (AFRA). As this classification is not always strictly followed, the shipping industry includes LR 2 under the Aframax or Suezmax categories. Suezmax are medium to large-sized tanker vessels with a deadweight tonnage (DWT) ranging between 120,000 to 200,000. They are the largest marine vessels that meet the restrictions of the Suez Canal. The typical Suezmax tanker deadweight is about 150,000 tonnes. Aframax are medium-sized crude tankers with a deadweight tonnage (DWT) ranging between 80,000 and 120,000. The tanker has a crude-carrying capacity between 70,000 and 100,000 metric tonnes of crude. Due to their size, Aframax tankers are able to enter most ports in the world.
Very Large Crude Carriers (VLCC): VLCCs are very large size tankers with deadweight tonnage ranging between 180,000 to 320,000. These vessels are extensively found around the North Sea, the Mediterranean, and West Africa. They are used in ports that have depth limitations but they offer a good flexibility in terms of terminal usage.
Ultra Large Crude Carriers: ULCC or Ultra Large Crude Carriers are the largest operating cargo vessels in the world with a size ranging between 320,000 to 550,000 DWT. Due to their colossal size, they require custom built terminals thus being able to serve a limited number of ports worldwide. These vessels are designed for very long distance crude oil transportation, especially from the Persian Gulf to Europe, Asia, and North America.
Classification of Tankers by Function:
Oil Tankers are mainly classified into two categories, product tankers, and crude carriers.
- Product tankers: When refined, crude oil separates into various oil products. The lightest of them are the clean products such as gasoline, kerosene, gasoil and the heaviest are the dirty products known as fuel
oils. The differences between the clean and dirty product tankers are the following:
- Clean product tankers are characterized by higher and more advanced segregation systems and they can load separate grades of cargo without the risk of contamination.
- Dirty product tankers, do not accommodate complex segregation systems and they are equipped with heating coils
- Crude Carriers: Crude Oil cargoes are homogenous but also different grades of crude oil are carried on the same ship without contamination risk as the oil will be refined after delivery. The main mission of crude carriers is the carriage of the crude oil from the oil-producing countries to the refineries around the world. These vessels have simpler pipeline systems when compared to the product tankers.
These vessels comprise a very specialized form of tanker. The two types of gas carriers are known as LNG (Liquefied Natural Gas) and LPG (Liquefied Petroleum Gas). The LNG is the methane product while the LPG Carriers are used to load mainly propane and butane.
One of the most technologically advanced type of vessels, chemical tankers are used for the carriage of any liquid chemicals in bulk and they are generally of small size from about 5,000 tonnes DWT to about 25,000 DWT while there are also a few chemical tankers up to about 50,000 tonnes deadweight (deep sea tankers). Chemical tankers are mainly used in two trades: For the carriage of extremely hazardous oils (IMO 1) and the carriage of edible and vegetable oils as well as very clean oil products (IMO 2 / IMO 3). In order to carry hazardous cargoes with safety, these vessels need to meet and satisfy very high standards.
Container ships transport huge quantities of cargo compacted in different types of containers. These ships are designed to load and transport shipping containers like 20 and 40 feet., standard containers, high-cube containers, flatrack (with collapsible sides) and platform containers (used for oversized cargo), open-top containers (with convertible top for materials of larger height), tank containers (for liquid materials / gasses) and refrigerated containers (temperature regulated containers). Within each container ship, there are several holds that separate each container from each other. Containers are usually loaded by specialized cargo cranes or even general purpose cranes with container lifting attachments to allow self-loading/discharging. These container vessels are geared and cost more to acquire and to maintain than gearless containers as they can use ports that are lacking ship-to- shore crane infrastructure. Each vessel defines its maximum capacity for each of the two size categories of container (20 or 40 feet). Depending on the TEU (twenty-foot equivalent unit) size and hull dimensions, container vessels can be distinguished into 7 major size categories:
- Small feeder up to 1,000 TEU (typically operate between smaller container ports)
- Feeder 1,001-2,000 TEU (typically operate between smaller container ports)
- Feedermax 2,001-3,000 TEU (typically operate between smaller container ports)
- Panamax 3,001-5,100 TEU
- Post-Panamax 5,101-10,000 TEU
- New Panamax 10,000-14,500 TEU and
- Ultra-Large Container Vessels (ULCV, 14,501 TEU plus).
Container vessels range in size from small, for those with max capacity of about 1000 TEU, to large, for those with max capacity of about 22,000 TEU. Large container vessels, due to their size, have draft restrictions to enter certain ports around the world. Nowadays, approximately 90% of non-bulk cargo worldwide is
transported by container, and new designs of container ships can carry over 21,000 TEU. Together with crude oil tankers and bulk carriers, containers are the biggest commercial vessels on the ocean and are expected to continue playing an important role in global shipping and trade. In 2016, global containerized trade expanded at a rate of 3.1 %, with volumes attaining an estimated 140 million 20-foot equivalent units (TEUs). The global containerized trade volume is expected to grow by approximately 4.5% at an annual compound growth rate up to 2026 (source: UNCTAD).