Childrens Illustrated Encyclopedia

RuddeR and

pRopelleR

a rotating propeller

forces the ship through

the water, and the rudder steers

the ship. When the rudder twists,

the weight of water thrusting

against it turns the ship.

HoW sHips float

although metal is very heavy, a ship

contains large spaces filled with air.

the hull (main body)

of a ship pushes water

out of the way, and

the water pushes

back on the ship

with a force called

upthrust. the

upthrust balances

the weight of the ship

and keeps it afloat.

463

eveR since ouR eaRliest ancestors discovered that

wood floats on water, ships and boats have played a major

part in human history. the first boats helped people

cross streams and rivers and carried hunters into

shallow waters so they could go fishing. Better ways

of building ships and boats began to develop when

people left their homes to explore new territories.

since more than two-thirds of earth is covered by water,

these early explorers had to go out to sea to discover new

lands, and they needed vessels that could make long voyages.

ships and boats changed and improved over thousands of years

as distant nations began to trade and opposing navies fought battles at sea.

today, there are thousands of different types of ships and boats. ships

are seagoing vessels; boats are generally smaller

and travel on coastal or inland waters.

Kinds of sHips

there are many kinds of ships.

they range from passenger vessels

to cargo ships that carry goods of

all types to and from

the world’s ports.

tRaWleR

trawlers are engine-powered fishing

boats that drag a net (the trawl) along

the seabed in order to catch fish that

swim near the bottom of the sea.

cRuise lineR

liners are large ships that carry

passengers on scheduled routes. Most

liners are like floating hotels and take

tourists on lengthy cruises.

oil tanKeR

oil is transported at sea in huge

tankers. the engines and bridge

are at the stern to give more

storage space.

feRRy

ferries take people and goods

across a stretch of water. large

ferries carry cars, trucks, and

trains, as well as people.

caRgo sHip

every year, cargo ships carry

millions of tons of goods across the world’s

oceans. some cargo ships, called container ships,

carry huge loads piled up in large, steel boxes

that stack together like building blocks. the

largest ships of this kind carry more than

10,000 such containers.

Upthrust from water

pushing upward

Rudder

Propeller

Ships and boats 463-

Weight of ship

pushing

downward

Traditional craft such as this

Chinese junk are still used in

some parts of the world.

The front end of a ship

is called the bow.

A powerful diesel engine drives

one or more propellers at the

stern (back) of the ship.

Cabins for crew

to sleep in when

not on duty

The captain commands the

ship from the bridge, which

houses the steering wheel and

navigation instruments such as

compasses, radar equipment,

and charts.

Main body of

the ship is

called the hull.

Cargo is stored in a large compartment

below the deck, called a hold. Large

modern cargo vessels may have 12 or

more holds. Ships that carry fresh food

have refrigerated holds.

sHipBuilding

Modern ships are built of steel

plates welded together. ship-

builders make all the parts

separately and finally assemble the

ship in the shipyard. after months

of sea trials to check its safety, the

ship is ready for service. A crane (called a

derrick), driven by

steam or electricity,

is used to load and

unload cargo.

US_463_Ships_Boats_1.indd 463 09/02/16 5:28 pm