Pilotage Mark Powell Mole Valley Sub Aqua Club SAA - 101.

PilotageMark Powell

Mole Valley Sub Aqua ClubSAA - 101

Pilotage & Lights

Objectives

• At the end of this lesson you should know: the purpose of pilotage Many of the “signposts” used in pilotage how to obtain pilotage information from charts

Pilotage & Lights

Outline

• Pilotage and charts• Buoys and markers• Lights• Leading lines and lights• Natural pilotage features

Pilotage & Lights

What is Pilotage?

• Use of visible, physical features as guides• Pilotage is needed :

Close to shore or in confined waters In shallow or dangerous water

• Types of pilotage features … Lights and man made marks placed at key spots Identifiable natural features

Pilotage & Lights

Pilotage and Charts

• Charts show many pilotage symbols• Chart is a source of detailed local knowledge• Can use charts both ways …

Find nearby chart symbols and then look for them at sea

Measure direction of feature observed at sea and plot it on a chart

Pilotage & Lights

Lights and Markers

• Markers: buoys and posts used in pilotage• Have shape, colour, topmark and meaning• Markers may have lights for use at night• Lights identified by their flashes and colours

Pilotage & Lights

Lateral Markers

• Mark the edges of channels … Port marks the left bank on rising tide Starboard marks the right bank on rising tide Colour and shape: red cans and green cones

Port markers Starboard markers

Pilotage & Lights

Direction of Lateral Buoyage• Keep Red to left and Green to right in direction rising tide

• Example: On which side do you pass the lateral buoys?

• Going in direction of rising tide

• Going in direction of falling tideGoing in direction of falling tide

Pilotage & Lights

Direction of Rising Tide

Some places are confusing :

• Split Estuaries: Solent

• East coast estuaries

Direction of Buoyage symbol highlights the direction

Pilotage & Lights

Cardinal Markers

• Point to safe water

• Top mark : like 4 points of compass

• Colours :

•3 bands of yellow or black

• top marks point to black

• Often named on charts

• Light flashes : like hours on clock 9 quick flashes every 15 sec.Or 9 v. quick flashes every 10 sec.

“Safe water to the west”

Pilotage & Lights

All four Cardinal Markers

Danger

N

S

W E

White, VQ or Q

Q (3) ev. 10 sec. or,VQ (3) ev. 5 sec.

Q (6) + long fl. ev. 15s.,VQ (6) + long fl. ev. 10s.

Q(9) ev. 15 sec. or,VQ (9) ev. 10 sec.

Pilotage & Lights

Safe Water Marker

• Indicate start of deep water

• Round top mark

• Red and white colour

• May have a white Isophase or Occulting light

Pilotage & Lights

Isolated Danger Marker

• Indicate a hazard

• Two round top marks

• Red and black colour

• May have a White, Group Flashing 2 light

Pilotage & Lights

Special Markers

• Show boundary of administrative area

• Speed limit, swimming, anchoring

• May have a cross top mark

• Yellow colour

• May have a yellow light

Pilotage & Lights

Light symbols & characteristics

Visible for 10 Miles

MHWS

Sea level

Every 10 seconds

Group occulting 315m above

MHWS

Gp Oc(3).10s 15m 10M

Sample Characteristic

Sample Symbol

Pilotage & Lights

Light characteristics Chart AbbreviationDescription Characteristic

Alt. R.W.G.

F.

Alternating

Fixed

Flashing

Group flashing

Fl.

Gp F.(2)

Occulting

Group Occulting

Occ.

Gp Occ(3)

Quick flashing

Very quick flashing

Qk.Fl.

V.Qk.Fl.

Isophase

Morse

Iso.

Mo.(letter)

Pilotage & Lights

Chart symbols for buoys and lights

• Major light, minor light, light, light houseOc.R.4s 10M

Lt Lt Ho

G.Fl(2)

Fl.Y

Iso

Fl.R Fl.RFl.G Fl.G

•Lateral buoys and marks

•Cardinal buoys and marks

•Safe water buoys and marks

•Isolated danger buoys and marks

•Special buoys and marks

VQ(6)+L.Fl10sVQ(3)5s

Pilotage & Lights

Leading lines and lights

• Line indicates a safe course near hidden dangers• Often guide boats up inlets into harbour• Leading line formed by two markers – day use• Leading lights formed by two lights – night use• Lines shown on charts• Compass bearing of line shown on chart

Pilotage & Lights

Leading lines

084o

080o

100o090o

070o

Pilotage & Lights

Leading lights

356o

350o

010o000o

340o

Pilotage & Lights

Natural features for pilotage

• Fixed points … Individual rocks – often difficult to see and identify, can

be dangerous Shoreline – difficult to positively identify, can be

misleading Headlands and bays - can be misleading

• Directions and lines … Transits and compass bearings

• General areas … Depth – need to calculate tidal height, uncharted depth

changes

Pilotage & Lights

Summary

• Pilotage and charts• Buoys and markers• Lights• Leading lines and lights• Natural pilotage features

Pilotage & Lights

Self Check• What is the purpose of pilotage? When is it used?• Name some man-made & natural pilotage features• Describe all 5 types of buoy (shape, colour, lights and

meaning)?• What is the “direction of buoyage”? Its symbol?• What do these chart symbols indicate?

Iso Occ F. Gp.Fl

•What do these chart symbols indicate?

F Alt R.W.G 8MFl W 15s 30m 10M

235o