Blind pilotage lrg

Grunt Productions 2007

BLIND PILOTAGEA Brief By Lance Grindley

Definition:Definition:

‘‘The navigation of the ship through The navigation of the ship through restricted waters in low visibility restricted waters in low visibility with little or no recourse to the with little or no recourse to the visual observation of objects outside visual observation of objects outside the ship.’the ship.’


BLIND PILOTAGEBLIND PILOTAGE1.1. Navigation and PilotageNavigation and Pilotage

a)a) Primary method: VisualPrimary method: Visualb)b) Secondary method: RadarSecondary method: Radarc)c) Other methods: ‘NAVAIDS’Other methods: ‘NAVAIDS’

2.2. Fundamental Navigational Radar Fundamental Navigational Radar a)a) Stabilised in azimuthStabilised in azimuthb)b) Bearing accuracy ±1°Bearing accuracy ±1°c)c) Range accuracy better than 20 yds (depending on pulse Range accuracy better than 20 yds (depending on pulse

length)length)d)d) Anti-clutter controlsAnti-clutter controlse)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 milesf)f) Fitted with: Electronic Blind Pilotage SystemFitted with: Electronic Blind Pilotage System


PLANNINGPLANNING

TRACK - Chosen by Master, based on TRACK - Chosen by Master, based on visual plan.visual plan.

SAFE WATER - Delimited by Limiting SAFE WATER - Delimited by Limiting Danger Line (LDL):Danger Line (LDL):

Draught+2m-Height of Tide.Draught+2m-Height of Tide.


BLIND PILOTAGEBLIND PILOTAGE

• Where are we in relation to planned Where 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 course How far to run to the next course alteration ?alteration ?


Parallel Indices

2m


080(080)

020

(020

)

WO

7.6c

4.0c

5.2c



080(080)

020

(020

)

WO

7.6c

4.0c

5.2c

NMT 11c

NLT 2c

NMT 13c

NLT 1c



080(080)

020

(020

)

WO

7.6c

4.0c

5.2c

NMT 11c

NLT 2c

NMT 13c

NLT 1c

6.2c





270 (270)

1m

NLT 4c

NL

T 5

c

1.3m

NL

T 3

c

1.4m


IN POSITIONIN POSITION


Radar Radar ErrorsErrors

Index ErrorsIndex Errors


True RangeTrue Range

Displayed Radar Range

Displayed Radar Range

Index ErrorIndex Error

Ie +/- 50 ydsIe +/- 50 yds


FINDING THE INDEX FINDING THE INDEX ERROR TWO MARK ERROR TWO MARK

METHODMETHOD

A = True range ± IEA = True range ± IEB = True range ± IEB = True range ± IEC = Charted C = Charted distancedistance

Index error = Index error = C – (A + B)C – (A + B)22

AA BB

CC

Index errorIndex error


Three Mark MethodThree Mark Method


False EchoFalse Echo


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.



Index ErrorsIndex Errors Strobe AccuracyStrobe Accuracy


Distortion caused by beam width

Direction ofAerial Rotation

A2

A1

B

C

D

Coastline

E



Index ErrorsIndex Errors Strobe AccuracyStrobe Accuracy Error introduced by controlsError introduced by controls




Index ErrorsIndex Errors Strobe AccuracyStrobe Accuracy Error introduced by controlsError introduced by controls Inaccuracies by not using shortest Inaccuracies by not using shortest

range scalerange scale




range scalerange scale Sloping beach/HOTSloping beach/HOT






range scalerange scale Sloping beach/HOTSloping beach/HOT


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 new Recommend come right to new course 095 to regain”course 095 to regain”

Career

Blind pilotage lrg