This document discusses blind pilotage, which is navigating a ship through restricted waters with limited visibility. It describes how radar is used as the primary method of navigation in these conditions. It also outlines some of the errors that can occur with radar, such as index errors, strobe accuracy issues, and errors introduced by controls. The document provides guidance on planning a track, monitoring position relative to the track, and maintaining safe water while blind piloting a ship.

1. Grunt Productions 2007
BLIND PILOTAGE
A Brief By Lance Grindley

2. Definition:Definition:
‘‘The navigation of the ship throughThe navigation of the ship through
restricted waters in low visibilityrestricted waters in low visibility
with little or no recourse to thewith little or no recourse to the
visual observation of objects outsidevisual observation of objects outside
the ship.’the ship.’

3. Grunt Productions 2007
BLIND PILOTAGEBLIND PILOTAGE
1.1. Navigation and PilotageNavigation and Pilotage
a)a) Primary method: VisualPrimary method: Visual
b)b) Secondary method: RadarSecondary method: Radar
c)c) Other methods: ‘NAVAIDS’Other methods: ‘NAVAIDS’
2.2. Fundamental Navigational RadarFundamental Navigational Radar
a)a) Stabilised in azimuthStabilised in azimuth
b)b) Bearing accuracy ±1°Bearing accuracy ±1°
c)c) Range accuracy better than 20 yds (depending on pulseRange accuracy better than 20 yds (depending on pulse
length)length)
d)d) Anti-clutter controlsAnti-clutter controls
e)e) Range scales (1007)Range scales (1007)
0.5, 0.75, 1.5, 3, 6, 12, 24, 48 miles0.5, 0.75, 1.5, 3, 6, 12, 24, 48 miles
f)f) Fitted with: Electronic Blind Pilotage SystemFitted with: Electronic Blind Pilotage System

4. Grunt Productions 2007
PLANNINGPLANNING
 TRACK - Chosen by Master, based onTRACK - Chosen by Master, based on
visual plan.visual plan.
 SAFE WATER - Delimited by LimitingSAFE WATER - Delimited by Limiting
Danger Line (LDL):Danger Line (LDL):
Draught+2m-Height of Tide.Draught+2m-Height of Tide.

5. Grunt Productions 2007
BLIND PILOTAGEBLIND PILOTAGE
• Where are we in relation to plannedWhere are we in relation to planned
track ?track ?
• How much safe water remains ?How much safe water remains ?
• How far to run to the next courseHow far to run to the next course
alteration ?alteration ?

6. Grunt Productions 2007
Parallel Indices
2m

7. Grunt Productions 2007
080(080)
020(020)
WO
7.6c
4.0c
5.2c

8. Grunt Productions 2007

9. Grunt Productions 2007
080(080)
020(020)
WO
7.6c
4.0c
5.2c
NMT 11c
NLT 2c
NMT 13c
NLT 1c

10. Grunt Productions 2007

11. Grunt Productions 2007
080(080)
020(020)
WO
7.6c
4.0c
5.2c
NMT 11c
NLT 2c
NMT 13c
NLT 1c
6.2c

12. Grunt Productions 2007

13. Grunt Productions 2007

14. Grunt Productions 2007

15. Grunt Productions 2007
270 (270)
1m
NLT 4c
NLT5c
1.3m
NLT3c
1.4m

16. Grunt Productions 2007
IN POSITIONIN POSITION

17. Grunt Productions 2007
RadarRadar
ErrorsErrors
 Index ErrorsIndex Errors

18. Grunt Productions 2007
True Range
True Range
Displayed Radar Range
Displayed Radar Range
Index ErrorIndex Error
Ie +/- 50 ydsIe +/- 50 yds

19. Grunt Productions 2007
FINDING THE INDEXFINDING THE INDEX
ERROR TWO MARKERROR TWO MARK
METHODMETHOD
A = True range ± IEA = True range ± IE
B = True range ± IEB = True range ± IE
C = Charted distanceC = Charted distance
Index error =Index error = C – (A + B)C – (A + B)
22
AA BB
CC
Index errorIndex error

20. Grunt Productions 2007
Three Mark MethodThree Mark Method

21. Grunt Productions 2007
False EchoFalse Echo

22. Grunt Productions 2007
Two Ship MethodTwo Ship Method
Compare B to A to find Index Error. IE = B - A = C - 2ACompare B to A to find Index Error. IE = B - A = C - 2A
A(IE)A(IE)
Range (A) between own ship and other incorporates Index Error.Range (A) between own ship and other incorporates Index Error.
C (IE)C (IE)
Range (C) between own ship and false echo also incorporates Index Error.Range (C) between own ship and false echo also incorporates Index Error.
B(No IE)B(No IE)
True Range is therefore C-A which equals B.True Range is therefore C-A which equals B.

23. Grunt Productions 2007
RadarRadar
ErrorsErrors
 Index ErrorsIndex Errors
 Strobe AccuracyStrobe Accuracy

24. Grunt Productions 2007
Distortion caused by beam width
Direction of
Aerial Rotation
A2
A1
B
C
D
Coastline
E

25. Grunt Productions 2007
RadarRadar
ErrorsErrors
 Index ErrorsIndex Errors
 Strobe AccuracyStrobe Accuracy
 Error introduced by controlsError introduced by controls

26. Grunt Productions 2007

27. Grunt Productions 2007
RadarRadar
ErrorsErrors
 Index ErrorsIndex Errors
 Strobe AccuracyStrobe Accuracy
 Error introduced by controlsError introduced by controls
 Inaccuracies by not using shortestInaccuracies by not using shortest
range scalerange scale

28. Grunt Productions 2007
RadarRadar
ErrorsErrors
 Index ErrorsIndex Errors
 Strobe AccuracyStrobe Accuracy
 Error introduced by controlsError introduced by controls
 Inaccuracies by not using shortestInaccuracies by not using shortest
range scalerange scale
 Sloping beach/HOTSloping beach/HOT

29. Grunt Productions 2007

30. Grunt Productions 2007

31. Grunt Productions 2007
RadarRadar
ErrorsErrors
 Index ErrorsIndex Errors
 Strobe AccuracyStrobe Accuracy
 Error introduced by controlsError introduced by controls
 Inaccuracies by not using shortestInaccuracies by not using shortest
range scalerange scale
 Sloping beach/HOTSloping beach/HOT

32. Grunt Productions 2007
EXECUTIONEXECUTION
 Ensure chart and PI’s are accurate.Ensure chart and PI’s are accurate.
 Conduct time check.Conduct time check.
 Maintain constant commentary -Maintain constant commentary -
“30 yds port of track with a“30 yds port of track with a
further 150 yds of safe water to port.further 150 yds of safe water to port.
3 cables to run to the wheel over.3 cables to run to the wheel over.
Recommend come right to newRecommend come right to new
course 095 to regain”course 095 to regain”