MODERN SHIPS
Modern ships and boats can be categorized by the jobs they do. Merchant ships include cruise liners, ferries, cargo ships, and utility ships, such as dredgers and tugs. Military ships include warships and support ships, called auxiliaries. There are also numerous different types of fishing boat and leisure craft, from luxury yachts to sailing dinghies.
Small cargoes are carried in standard-sized metal boxes called containers on container ships, which are loaded and unloaded at dedicated container terminals. Cargoes such as ores, coal and grain are carried by bulk carriers. Oil and other liquids are carried by tankers.
The main part of a ship is its hull, the part that sits in the water. It keeps the ship watertight and forms a strong structure that supports the other parts of the ship and its cargo. Inside the hull are horizontal decks and vertical walls called bulkheads.
The parts of a ship above the main deck are called its superstructure. Most ships have a diesel engine housed low in the hull, which drives a propeller under the stern via a shaft. A rudder at the stern steers the ship. Large ships also have small electrically powered propellers called thrusters for manoeuvring accurately in port.
The SeaCat is a high-speed vehicle ferry. It is a catamaran, which means it has two hulls. Fast ferries like this are powered by gas turbine (jet) engines, giving them top speeds in excess of 40 knots (70 km/h).
Different types of ship have their own specialized parts. For example, vehicle ferries called roll-on roll-off (ro-ro) ferries, designed for a quick turnaround in port, have huge bow or stern doors, and uncluttered decks where the vehicles park. Container ships have their own on-deck cranes for moving containers about. Aircraft carriers have a flat main deck that forms a runway where aircraft take off and land, with hangars underneath.
A giant Nimitz-class aircraft carrier dwarfs a 15th-century carrack. The nuclear-powered Nimitz- class carriers are the world’s largest. They weigh nearly 100,000 tonnes and have a flight deck 333 m long. They provide an operations base for nearly 100 attack aircraft.
Ships are controlled from a room high up near the bow, called a bridge. From here, the crew navigates from place to place, using engine and steering controls, and keeping track of their position using charts, satellite navigation systems, lighthouses and buoys. Radar helps to avoid collisions at night or in fog, and sonar warns of shallow water under the ship.
Picture Credit : Google