How Much Load Can A Cargo Ship Carry?

Cargo Ship Capacity: How Much Can They Carry?

First of all, the weight of a ship is a very interesting aspect. Unlike other physical objects, when we talk about the weight or mass of a ship or any floating object, we usually refer to displacement.

We know that this displacement is no greater than the mass of the floating structure itself and, according to the Archimedean principle, is also equal to the mass of water displaced by the ship to remain afloat. This quantity is sometimes also expressed as volumetric displacement, which refers to the volume of water displaced by weight, which is equal to the weight of the container.

Cargo Ships classifications

Displacement can be divided into:

• Light
• Deadweight

Lightweight is basically the inherent weight of the ship itself, including the structural weight of the ship, as well as the weight of systems, machinery, equipment, lines, pipes, ducts, wiring, equipment, etc. Deadweight is the weight that the ship can carry: cargo, consumables, fuel, fresh water , ballast, people (passengers or crew), stores, and other items. Therefore, a ship that does not have all the elements included in deadweight is a lightship.

While displacement is a general name for any ship, for practical purposes, ship capacity is a more specific definition based on the type of ship. Common cargo and commercial ship types, such as passenger ships, can be referred to in various ways, which can often be confusing.

For example, a passenger ship is usually referred to by its maximum passenger capacity rather than displacement. For example, a ferry with a capacity of 1,000 passengers can accommodate a maximum of 1,000 people. Deadweight tonnage is another very common term that refers to a ship's maximum carrying capacity, expressed in weight. It is nothing more than a measure of how much a ship can carry.

In our previous article, we learned about other standardized metrics such as Gross Tonnage (GT) and Net Tonnage (NT).

In simple terms, Gross Shipping Area is determined by the total space available inside the ship, while the Gross Shipping Area is determined by the space inside the ship that generates commercial revenue, i.e., space allocated to cargo, merchandise, or consumers (passenger ships).

It is very different from deadweight as it covers the total transportable weight of the ship, including other deadweight consumables such as fuel, lubricants, ballast, water, consumables, etc. Cargo ships are usually classified according to their purpose and utility.

Bulk Carriers and Similar Vessels

These vessels are primarily used to carry dry bulk cargoes and are classified according to their deadweight (or, more commonly, deadweight). So when a bulk carrier is certified to carry 100,000 metric tons, it means that the ship can carry up to 100,000 metric tons of cargo in its cargo holds.

Bulk Carriers

As we know from many of our previous articles, bulk carriers vary greatly in size, from 500 tons to 300,000 tons. The Pacific Flourish is the largest bulk carrier currently in operation, with a maximum cargo capacity of nearly 400,000 tons.

The broadest category of bulk carriers is general-purpose ships , which can carry a wider range of cargo types but generally only dry cargo. Similarly, other special subtypes of bulk carriers include ore carriers, coal carriers, timber carriers, etc., which refer only to their deadweight tonnage. In addition to DWT, dry bulk carriers generally use GT and NT. Tankers and similar vessels carrying liquid cargoes

Oil tankers

Like bulk carriers, tankers are classified according to their deadweight (dwt), gross tonnage (GT), and gross weight (TN) expressed in tons. This category includes oil tankers, gas tankers , chemical tankers , etc. Tankers' size depends on the maximum amount of liquid cargo they can carry. Like bulk carriers , tankers' deadweight also varies greatly, from 500 tons to more than 400,000 tons.

Container ship

It is one of the most common types of commercial cargo ships, and the cargo is presented in the form of standard containers . Its gross displacement tonnage does not mainly determine it but by the maximum number of containers it can transport.

Remember those TEU units we mentioned several times? Container ships are primarily classified by TEU. So a container ship with a capacity of 10,000 TEU can carry up to 10,000 standard-sized TEUs. Conversely, it can carry 5,000 2-TEU containers or a combination of 5,000 1-TEU containers and 2,500 2-TEU containers.

Other types of ships, such as RoRo and RoPax

Other types of merchant ships can be described in different ways. RoRo ships are mainly used to transport wheeled goods such as cars and are identified by special units such as railway meters. By convention, 1 meter of aisle is equivalent to 2 square meters of surface area.

RoRo ships

The total load of roRo vehicles can be calculated based on the size of the vehicle and the available track space. RoRo ships carry vehicles and passengers and are defined by the combined result of their lane length and passenger capacity. Sometimes, this type of ship is also defined simply by the number of vehicles it can carry. They are also called GT or NT.