All the ships in the world are different from one other by their structures, sizes, deadweight, type of cargo they are carrying or nature of cargo.
The best way i think which differentiate the different types of ships will be by the nature of cargo they carry.
Book to teach your kids about different types of Ships
Types Of Ships
Ocean liners are traditional passenger ships. An ocean liner typically has 1,500 to 2,000 seats for passengers and has facilities of saloons, swimming pools, and sports halls. Prior to advent of airliners, they were the primary mode of intercontinental travel. Nowadays, just a few ocean liners are in operation, their place has been taken by ferries. Some of the famous and most luxurious ocean liners of the past are the Titanic, Olympic, and Queen Elizabeth. The largest ocean liner today is RMS Queen Mary 2.
Ferries are boats or small-sized ships that are used for day or overnight short sea trips sailing close to the coast between two or more ports. With a seating capacity ranging from 40 to 600, ferries are part of public transport systems in many waterside cities and islands. They are categorised into the ship types such as Hydrofoil, Hovercraft, Catamaran, Cruise ferry, Ro-ro, Pontoon ferry, Foot ferry, Cable ferry and Air ferries.
There are many ships that are constructed or converted for specialized purposes, like dredging, exploration, offshore construction, work gang ships (these are for housing workers in areas where there is no onshore living quarters), or for specialized cargo. For example, banana boats that are not much more than small general cargo ships. Banana boats are nasty damn ships, for down in their holds one may come across very large spiders
These ships will mostly have four or five holds (a hold is the cargo space in a ship), with one or, in a few cases, two holds aft of the engineroom, and four to five holds generally forward of the engineroom. They have long protruding rigging for winches by each hold. These winches are used to load and unload the cargo. The cargo is usually packaged and moved as single parcels, or assembled together on pallet boards. Longshoremen go down into the holds to hook up the cargo to be lifted out. Some general cargo ships may also have refrigerated spaces for perishable cargo. The average general cargo ship is about 500 feet long.
Like general cargo ships bulk carriers will have large hydraulic hatches covering the holds, but will not have any overhead rigging. Bulk carriers are used for things such as grain, ore, wood chips, etc, that can be poured down into a hold. They will load and off-load at special port terminals for whatever cargo they may carry. Sometimes the holds must be steamed cleaned by laborers when the ship is set to carry a different cargo than the one that it unloaded. The average bulk carrier ship is around 800 feet long.
The advantage of using containers is that all the cargo in each container will be destine for some location away from the port taken there by either truck or rail. This does away with the warehouses that are needed for general cargo ships where the cargo is divided up and loaded into truck trailers or railcars. Container ships come in many different sizes; some now are incredibly huge.
Vessels specially designed for efficient transport of cars (pure car carriers), or variety of cars, trucks, tractors and buses (pure car/truck carriers). Cargo access/transfer equipment of typical car carrier consists of a stern quarter ramp, side ramps, internal ramps with covers and hoistable decks. Vehicles drive directly into the ship and via internal ramp system to various decks.
8. Ro-Ro Carrier
Roll-on/roll-off (RORO or ro-ro) ships are designed to carry wheeled cargo, such as cars, trucks, semi-trailer trucks, trailers, and railroad cars, that are driven on and off the ship on their own wheels or using a platform vehicle, such as a self-propelled modular transporter. This is in contrast to lift-on/lift-off (LoLo) vessels, which use a crane to load and unload cargo.
RORO vessels have either built-in or shore-based ramps or ferry slips that allow the cargo to be efficiently rolled on and off the vessel when in port. While smaller ferries that operate across rivers and other short distances often have built-in ramps, the term RORO is generally reserved for large oceangoing vessels. The ramps and doors may be located in stern, bow or sides, or any combination thereof.
9. Crude Oil Tanker
Crude tankers move large quantities of unrefined crude oil from its point of extraction to refineries. For example, moving crude oil from oil wells in a producing country to refineries in another country.
10. Product Tanker
Product tankers, generally much smaller, are designed to move refined products from refineries to points near consuming markets. For example, moving gasoline from refineries in Europe to consumer markets in Nigeria and other West African nations.
11. LPG carrier
An LPG carrier or LPG tanker is a gas carrier/gas tanker ship designed for transporting liquefied petroleum gas (LPG) in bulk
12. LNG carrier
An LNG carrier is a tank ship designed for transporting liquefied natural gas (LNG). As the LNG market grows rapidly, the fleet of LNG carriers continues to experience tremendous growth.
13. LASH vessel
A Lighter Aboard Ship or LASH vessel is a less well-known type of vessel that features an onboard crane for loading and unloading the floating cargo. Within this context, lighter does not refer to the crane but to the barge or sloop. Although the name could suggest that it involves various types of cargo, in practice, they are nearly always standardised pushed barges or lighters.
After having been unloaded, the pushed barges can be linked up and shipped further inland, without the need for transhipping. Visa versa, the cargo can also be shipped in via inland navigation. The term lighter is probably derived from the Dutch and/or German language: in the past, sloops or barges (called a lichter, in Dutch or German) were moved alongside the ship to transfer the cargo into.
14. Cattle Carriers
A livestock carrier or Cattle Carriers is a large ship used in the live export of sheep, cattle and goats. They are specially built new or converted from container ships
Book to teach your kids about different types of Ships