Radar is used for collision avoidance, navigation, and pilotage. The radar screen displays range rings and a ship's head marker. International regulations require proper use of radar if fitted, including long-range scanning to obtain early warning of risk of collision and radar plotting. Assumptions should not be made based on limited radar information. Regulations also specify radar reflector size requirements. Collision avoidance using radar follows the rules to alter course depending on sector of detected vessels. Different radar display modes like head-up and north-up have benefits and drawbacks. Factors like range, target size and material, and false or interference echoes must be considered when using radar. Attending an RYA radar course is recommended prior to use.

1. RADAR

2. Main uses of radar
 Collision avoidance i.e. look-out,
plotting, finding course & speed,
finding closest point of approach,
determining risk of collision
 Navigation i.e. range, bearings,
mixed fixes
 Pilotage i.e. clearing lines

3. BREAK DOWN OF A RADAR SCREEN
Range
rings
Ships
head
marker

4. IRPCS & the use of radar
 Rule 5 (Lookout), Rule 6 (Safe speed),
Rule 7 (Risk of collision), Rule 19 (conduct
in restricted visability
 Rule 7b
“Proper use shall be made of radar
equipment if fitted and operational,
including long range scanning to obtain
early warning of risk of collision and radar
plotting or equivalent systematic
observation of detected objects.”
 Rule 7c
“Assumptions shall not be made on the basis
of scanty information, especially scanty
radar information.”

5. SOLAS regulations
 Specifies that you must have a radar
reflector !
 If your craft is over 15m in length
then it must be a specific size.

6. Collision avoidance
Alter course as follows in
collision situations
depending on what
sector the other craft
appears.
This method of collision
avoidance matches Rule
19 for radar users
(conduct in restricted
visability)

7. POSITIVE:
The virtue of
head-up mode
is that the
picture
corresponds to
the view from
the helm.
DRAWBACK:
When you alter
course, the
picture rotates.
This can make it
difficult to spot
weak contacts.

8. Postives:
Picture
corresponds to
chart.

9. Postive:
Similar look to
HU.
Good for
collision
avoidance but
needs to be
reset whenever
you alter your
course

10. Principles
 RANGE
Depends on height of scanner & target
Effected by the horizon
 TARGETS
Signal depends on size, material,
aspect, texture, shape i.e. a port
marker will show up better than a
starboard marker

11. Beware !
 False echos
 Side echos – i.e. when a boat goes
past you there can be a repeated
appearance on screen
 Shadows – i.e. blind spots
 Interference – i.e. from another
radar
**ATTEND AN RYA RADAR COURSE
PRIOR TO USE !**