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The broadest classification of ships by use distinguishes them as Men of War or Warships and Merchant Ships. Any list of warships by types uses soon becomes obsolete because during every war and between wars to a lesser extent, certain types of ships tend to disappear while new types are built as the result of the invention of new weapons or the development of new tactics.
Sea-going merchant ships can be classified according to different criteria, as for example by the trade of service in which they are engaged, the kind of cargo they carry, the type of machinery they use, the building system they use, the tonnages etc.
Sea-going ships are generally built with their for and aft line perpendicular to the shore line, i.e. they are built and launched endwise while river boats are usually built parallel to the water, i.e. they are built broadside and launched sideways.
Considering the service in which merchant ships are engaged, they may be further subdivided into passenger ships for the transportation of passengers and cargo ships or freighters which are used for the carriage of different kinds of cargo, such as bulk cargo, liquid cargo, containers, etc. In addition to these, there exist special types of ships as for example ferry boats, tugs, dredgers, icebreakers, yachts and many others.
Classification of cargo ships. Cargo ships are classified according to the kind of cargo they carry. The following list gives the names of those which are most commonly built today.
1.General Cargo Ships 8. Container Ships
2.Bulk Carriers 9. Oil Tankers
3.Ore Carriersa) Crude Oil Carriers
4.Bulk Ore Carriers b) Product Carriers
5.Dry Cargo Ships 10. Liquified Gas Carriers
6.OBO Ships (ore, bulk, oil) 11.LNG Carriers (liquid natural gas)
7.Refrigerated Cargo Ships
Those cargo ships or passenger ships that keep a definite route on their voyage may also be called liners, and those engaged in service or trade along the coast – coasters. Cargo ships are spoken of as cargo-passenger ships if they are provided with some accommodation for passengers.
Lloyd’s Register of Shipping issues an annual report for every year which besides other information and technical data gives a task of propulsion analysis of world tonnage. According to this criteria ships may be classified into steamships and motorships. Steamships may be propelled by:
a) Reciprocating Steam Engines
b) Reciprocating and LP Turbine (Low Pressure Turbine)
c) Steam Turbine Engines
d) Turbo Electric Drive (Turbo Generators)
Motorships may be propelled by:
a) Diesel Engines (Marine Diesels)
b) Diesel Electric Drive (Diesel Generators)
Some new ships specially designed for gas turbine propulsion are now in service. A ship, which represented a spectacular new development in container transport, was EUROLINER, which was the world’s first container ship propelled by a gas turbine.
Some nuclear ships propelled by a nuclear power plant have also been built in recent years.
Types of Boats. Boats are vessels of small size usually made of wood or some kind of plastics, for example fiberglass. They may be propelled by a petrol or diesel engine, or they may be provided with sails which use the force of wind for their forward motion. The simplest and smallest boats are only provided with oars and they use manpower for going ahead or astern. The following types of boats are in common use: rowing boats, sailing boats of different types, fishing boats, motorboats, life boats, etc.
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