unit 4 navigation aids

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UNIT 4

NAVIGATION

NAVIGATION AIDS



Navigation aids are means designedto assist a navigator to determine safe

course or to warn of dangers or

obstructions to navigation.



Navigation aids include lighthouses,

lightships, buoys, beacons etc.



IALA (International Association of

Lighthouse Authorities) endorsed two

buoyage systems in 1977.

Region A (IALA A) covers all of Europe

and most of the rest of the world

whereas region B (IALA B) covers only

the America, Japan, the Philippines andKorea.



All marks within the IALA system are

distinguished by

shape,colour,

top mark light



Identification of navigation aids is

accomplished by observing their location, shape, colour scheme,

auxiliary features (sound signals,

RACON etc.) and markings (name,number, etc) during daytime



At night, light is only way of identification

and has three features:

colour,period

phase characteristic



Phase characteristics are the distinctive

sequences of light and dark intervals in

the variations of the intensity of light.



The common types are fixed, flashing,

quick flashing, very quick flashing,interrupted quick flashing, isophase,

occulting, alternating, group and long

flashing.



BEACONS

Beacons are fixed aids to navigation

attached to the bottom of the waterway or ashore.

Lighted beacons are called lights;

unlighted beacons are daybeacons.



LIGHTHOUSES

Lighthouses are major structures with

distinctive colour, light sequences and

sound signals.

Lighthouses help navigators determine

location and warn of potential hazards.

The necessary information aboutlighthouses can be found on charts.



LIGHTSHIPS

Lightships are vessels which carry theentire equipment standard to a lighthouse.



BUOYS

Buoys are floating aids to warn navigatorsagainst potential dangers.

Buoy types are:

Lateral

Cardinal

Isolated danger

Safe water

Special



The location of lateral buoysdefines the borders of channels

and indicates the direction.



Cardinal buoys indicate the safe sideof a danger with an approximate

bearing.



Basic buoy shapes are

can

conesphere

pillar

spar.



Buoys can be lighted or unlighted.

The information about buoys can

be found on charts.



ANSWER THESE QUESTIONS

1-What are the purposes of

navigational aids?



2-What are the differences between

lighthouses and lightships?



3-What is the coverage of region B?



4-What are the basic features of lights?



5-What are the types of buoys?



6- Do lighthouses have sound signals?



7- What are the main buoy shapes?



8- Are buoys and beacons fixed?



SOME WORDS

Cardinal System (n)- The aids areassigned shape, colour, and number

distinction in accordance with location

relative to obstructions.



Daybeacon (n) - An unlighted fixed

structure equipped with dayboards.



Isophase (adj.)- Referring to a lighthaving a characteristic of equal intervals

of light and darkness.



Lateral System (n)- A system of aids in

which the shape, colour and number areassigned in accordance with navigable

waters.



RACON (n)- A device that, on receiving

radar signals, transmits coded signals in

response to help navigators determine

their position



Explain the difference between two

words

a) Coast

b) Shore



a) Radio navigation

b) Satellite navigation



a) Lighthouse

b) Lightship

‘ M i i



‘ Means to assist a navigator to

determine safe course or warn of dangers

to navigation’ defines

a. navigation instruments

b. celestial navigation

c. deduced reckoning

d. compasses e. navigation aids

‘ M t i t i t t



‘ Means to assist a navigator to

determine safe course or warn of dangers

to navigation’ defines

e. navigation aids



Which is not a mark distinguishing way

in IALA system?

a. shape

b. colour c. top mark

d. gravity

e. light



Which is not a mark distinguishing way

in IALA system?

d. gravity



Mooring buoy is a …… buoy.

a. lateral

b. cardinal

c. isolated danger

d. safe water

e. special



Mooring buoy is a …… buoy.

e. special

i



Who endorses the light and buoyage

for navigation?

a. IALA

b. ITU c. WMO

d. INMARSAT

e. ILO

Wh d h li h d b



Who endorses the light and buoyage

for navigation?

a. IALA

unit 4 navigation aids

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