pilotage mark powell mole valley sub aqua club saa - 101
TRANSCRIPT
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
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