The majority of international trade is carried by ships carrying goods. The variations between them are a reflection of the various modes of cargo transportation and the variety of cargo that can be conveyed. That explains why there are so many different kinds of freighter ships cruising the oceans.

Among the cargo ships that travel the oceans are container ships, bulk carriers, refrigerated cargo ships, or reefers, and ro-ro boats. The benefits and traits of each are listed below:

1. Bulk Carrier Vessel

Unpackaged products are typically transported on bulk carriers. They transport massive amounts of products that are made of a single commodity, such as wood, grain, ore, and fertilizers. In addition, they move raw goods, including cement, coal, and machinery.

The following groups comprise bulk carriers:

• Capesize: The largest dry freight ship in terms of size. Suitable for transporting at least 110,000 tonnes of raw materials, primarily grain or ore. It makes up 9% of the bulk carrier fleet globally.

• Panamax: The Panama Canal's size restrictions define this type of ship that transits the canal. With a normal cargo capacity of 60,000 tonnes for the older Panamax and nearly twice that for the New Panamax, both vessels have draughts of 40 to 42 feet. consists of around 19% of the fleet of bulk carriers.

• Handymax: Approximately 24% of the world's fleet of bulk carriers is made up of Handymax, which has a 30 to 35-foot draught and a 37,000-ton cargo capacity.

• Handysize: With a load capacity of 30,000 tonnes, the handysize class is smaller than the handymax class. They make up 48% of the fleet of bulk carriers.

Find out information What is bulk cargo? Discover the essentials of bulk shipping

2. Container ships 

Large ships known as "container ships," often known as "box ships," are built to carry standard containers such as 10’, 20’, 40’ , 45’ , as well as High Cube (HC) , Open Top (OT), Flat Rack (FR), Garments-On-Hanger (GOH) or refrigerated containers.

Due to their frequent use in international transportation, container ships are typically highly automated, and some of the newest versions even produce no emissions.

At present, the great majority of non-bulk cargo is transported globally by these vessels. Consequently, container ships carry the majority of marine cargo.

3. General cargo ships

In contrast to container ships, general cargo ships are designed to handle loose-packaged cargo of various kinds. The number of holds and number of decks of a standard cargo ship might vary.

This type of ship has its own set of cranes that are a part of the ship and are used to load and unload cargo when the ship is in port. This is one of the ship's key characteristics.

The diversity of goods it can carry and its adaptability earn it the moniker of multi-purpose vessel.

4. Roll-on/Roll-off or Ro-Ro Ships

The term "Roll-on, Roll-off" (abbreviated as "Ro-Ro") refers to the process of loading and unloading goods from a vessel. These ships transport wheeled cargo that is loaded either via a platform truck or the vessel's own wheels. Typically, a ship has a series of decks that are connected via stairs, elevators, and doors at the bow or stern.

All types of vehicles, including trucks, wheeled freight, and even trailers hauling containers, can be transported on these ships. These vessels are designed with an anti-heeling system that connects the ballast water tanks with cross-pipes and pumps.

5. Reefer ships

A reefer ship is a ship that carries perishable cargo and is chilled. To arrive at the port of destination in secure conditions, this specific cargo needs to be transported at a specific temperature.

The controlled temperature is between 12 and -30 degrees Celsius. The cargo space ranges between 100,000 and 600,000 square feet. The ships are typically painted white to reduce heat build-up since white reflects more light and generates less heat than other colors.

It is also important to note that these ships typically move more quickly than regular cargo ships because of the nature of the load.

6. Oil Tankers

An enormous vessel built for the bulk transportation of oil or its byproducts. Offshore berthing is possible for oil and gas vessels. has a capacity of two million barrels of oil.

7. Gas tankers

Ships made specifically to transport natural gas or liquefied gas. The nature of the cargo necessitates high-tech machinery and design, which raises the cost of building.

Gas tankers can be divided into two main categories: LNG (which transports liquefied gas at temperatures close to -170 °C) and LPG (which transports the cargo at -50 °C).

The vessel's main deck is lined with spherical tanks that are used to hold the chemical load.

8. Chemical tankers

A vessel used for the bulk transportation of chemicals like phenol, gasoline, or ammonia, among others. These cargo ships, which range in size from 5,000 to 35,000 or even 50,000 DWT, are not the biggest. Tanks on chemical tankers are made of stainless steel and have a double shell.

9. Livestock carrier ships

Particularly designed to transport several live animals and all of their travel necessities, including as food, medicine, and air ventilation. Some livestock trucks may have the pens erected on open decks.

10. Heavy-Lift ships

A very large or heavy load, such as industrial machinery, such as jet bridges or wind turbines, is what this item is designed to carry.

What additional criteria can cargo ships meet?

Aside from the numerous load types, there are other factors that can be used to classify cargo ships into different groups.  

Classification based on the frequency of the service

Cargo Liners operate between regular ports of call while transporting cargo and occasionally passengers, all while charging shippers a set contractual rate. Ocean cargo liners is another name for them. 

On the other hand, some ships travel without a set itinerary or a list of places of call. These boats are chartered by numerous users, some of which also use them to transport passengers. Tramp ships are typically used by smaller maritime firms whose fleets are insufficient to plan liner cruises. 

Classification based on the capacity of the ships

The size categories for vessels in service as of April 2020 are listed below. Deadweight tons (DWT) are the units used to quantify capacity: 

• Miniature Handy: 10,000 to 24,999 DWT 

• Size for portability: 28,000 to 40,000 DWT 

• Medium Handy: 35,000 to 39,999 DWT  

• 40–50 DWT, according to handymax 

• Traditional Supramax vessel: 50,000–60,000 DWT 

• In order to pass through the Panama Canal, a ship must be at least 60,000 to 80,000 DWT in size, or Panamax. 

• Vessels post-Panamax: 79,000 to 99,999 DWT 

• Medium-sized oil tankers known as Aframax range in size from 75,000 to 115,000 DWT and are larger than Suezmax ships but smaller than Panamax ships.

• Suezmax (the largest ship that can pass through the Suez Canal): approximately 150,000 DWT 

• Malaccamax: 280,000 to 300,000 DWT (the largest vessel that can pass through the Malacca Straits). 

• Seawaymax: 10,000 to 60,000 DWT (the largest vessel size permitted through the St. Lawrence Seaway's canal locks). 

• Ships classified as Capesize (those that can navigate the Cape of Good Hope and Cape Horn but not the Panama Canal or the Suez Canal) range in size from 100,000 to 129,999 DWT for a Mini Capesize to 130,000 to 199,999 DWT for a Standard Capesize to 200,000+ DWT for a Large Capesize.    

• VLCC (Very Large Crude Carrier): supertankers with a capacity of 150,000 to 320,000 DWT 

• Supertankers with a 320,000–550,000 DWT capacity are known as ULCCs (Ultra Large Crude Carriers). 

Frequent Questions Regarding Cargo Ships

1. What additional criteria are there for classifying cargo ships?