Ships can be classified in many ways by purpose, state of navigation, number of hulls, propulsion power, propeller, etc.

According to the purpose, ships are generally divided into military and civilian ships. Military ships are usually called ships or warships, and those with direct combat capability or sea protection capability are called combat ships, such as aircraft carriers, destroyers, frigates, missile boats and submarines, as well as mine-laying, mine-clearing vessels, etc., and those responsible for logistics support are called military auxiliary ships. Civil ships are generally divided into transport ships, engineering ships, fishing boats, harbor ships, etc.

According to Archimedes' principle, the weight of water discharged below the waterline of a ship is the buoyancy of the ship, and should equal the total weight of the ship. The weight of a ship is equal to the displacement of an empty ship. The total weight of the ship plus the weight of the loads loaded on the ship (deadweight) varies and is equal to the total weight of the ship.

The ship's deadweight includes the weight of cargo, fuel and lubricating oil, fresh water, food, personnel and baggage, spare goods and supplies, etc. The sum of the usual intended designed cargo capacity and the weight of oil, water, food, etc. calculated for the intended maximum voyage is called the designed cargo capacity. The displacement at design load is called design displacement or full load displacement.

The main dimensions of a ship include total length, design waterline length, length between perpendiculars, maximum ship width, shape width, shape depth, full load (design) draft, etc. The measurement of steel ship master scale refers to the size of the inner surface of the hull plate, known as the width and depth of the hull, cement ship, wooden ship, etc., refers to the size of the outer surface of the hull.

Capacity refers to the volume of the cargo hold, fuel tank, water tank, etc. It represents the loading capacity and endurance capacity of the ship from the aspect of capacity, and it affects the operation capacity of the ship. Registered tonnage is a measurement index left over from history to measure the loading capacity of ships, as one of the bases for buying and selling ships, paying taxes, and charging services. Registered tonnage and deadweight reflect the capacity of the cabin and the ship, respectively. Although they are related to each other, they are different concepts.

The shape chart is the shape and size of the surface of the main body of a ship (including bulwarks and forecastle and forecastle). It is one of the main drawings for the design and construction of a ship. It consists of three sets of lines: transverse, half-width and longitudinal. The three are respectively cut from the transverse section, waterplane and longitudinal section and the surface of the ship shape.

The general design of a ship is one of the main drawings for the design and construction of a ship. It reflects the ship's architectural characteristics, shape and size, the location and internal arrangement of various cabins, the arrangement of internal stairways, and the layout of deck equipment. The general arrangement is composed of side view, deck plan and double deck subdivision.

The hull structure diagram reflects the structure of each part of the hull. The structure of each relevant part of the hull is independent and interrelated. The main structure of the ship is the key to ensure the longitudinal and transverse strength of the ship. It is usually regarded as a hollow beam for design, and its component size and specifications are reflected by the structure diagram of the transverse section in the ship.

Classification by use

- Passenger ship: passenger transport ship.

- Cargo ship: cargo transport ship. Such as oil tanker, bulk carrier, container ship and so on.

- Cargo passenger ship: a cargo and passenger transport ship.

- Salvage operation vessel: used for maritime rescue work.

- Engineering ship: a salvage ship dealing with salvage work, a research ship engaged in scientific research, and an engineering ship dealing with the maintenance and repair of ships under sail. They all fall into this category.

- Navigational vessel: vessel indicating the course.

- Fishing vessel: A vessel used for fishing.

- Speedboat: A boat used primarily for water recreation, or rowing races. There are many types of motorboats, hovercraft belong to this type.

- Military ships: Ships for military purposes, such as cruisers, destroyers, submarines, etc., and ships owned by the military that are not themselves used for military purposes are also classified as such.

By material

Estimates suggest that more than 1,000 materials and 5,000 tons of steel are needed to build a 10,000-ton ship.

- Steel ship

- Wooden boat

- alloy ship

- Fiberglass ships

- Cement boat

Classification by material

- Monohull, multi-hull (catamaran, Trimaran, etc.). The most common type of ship is a monohull. Catamarans have two lanky hulls and use turbojet engines that spray water backwards to capture the reaction force and propel them forward faster than normal propellers. At high speeds, the catamaran's elongated hull reduces drag. And the hull is stable, not easy to capsize. It is often used in ferries and military transport.

Hydrofoil This is a kind of ship that can travel at high speeds. The bottom of the boat is braced with hydrofoil. As the boat accelerates, hydrofoils create buoyancy to lift the ship off the surface, reducing water drag and increasing speed.

- A hovercraft is a vessel that can travel at high speeds and uses air on its bottom liner to reduce the drag of water. Many hovercraft can reach speeds of over 50 knots.

Dynamic classification

hovercraft

- Hovercraft: The use of air above atmospheric pressure to form an air cushion between the bottom of the ship and the supporting surface, so that all or part of the hull from the supporting surface and high-speed sailing.

- Human-powered/animal-powered boats: Power is generated by human power, the use of OARS, etc.

- Sailboats: Use wind to blow sails to generate power.

- Schooner: wind - powered, engine - powered twin - powered boat.

- Ship: engine powered ship.

- Nuclear-powered ship: A ship that uses a nuclear reactor to generate power.

According to the sailing state of the ship, it can be divided into drainage type ship, coasting boat, hydrofoil boat and hovercraft.

According to the number of the hull of the ship can be divided into monomer ship and multi-hull ship, in the multi-hull type catamaran is more common;

According to propulsion power, they can be divided into motor ships and non-motor ships. According to the type of propulsion engine, motor ships can be further divided into steam engine ships (now obsolete), steam turbine ships, diesel engines, gas turbine engines, combined power plant ships, electric propulsion ships, nuclear power ships, etc.

According to ship propeller can be divided into propeller ship, water jet propulsion ship, jet propulsion ship, paddle steamer, flat rotary ship, air propeller is only used for a few hovercraft; According to the position of engine room, there are stern type ship (engine room at the tail of the ship), medium type ship and medium type ship; According to the hull structure material, there are steel boat, aluminum alloy boat, wooden boat, steel wire mesh cement boat, glass steel boat, rubber boat, mixed structure boat.

According to nationality, there are national vessels (ships registered in the home country and flying the flag of the home country) and foreign vessels (ships registered in a foreign country and flying the flag of a foreign country).

According to the distance of the voyage, it is divided into near sea ships and ocean ships. The navigability of the two is different.

The main technical characteristics of a ship include the displacement of the ship, the main dimensions of the ship, the hull coefficient, the storage capacity and the registered tonnage, the ship shape chart, the general arrangement of the ship, the hull structure chart, the specifications of the main technical equipment, etc.