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Pilotage. Mark Powell Mole Valley Sub Aqua Club SAA - 101. 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. Outline. Pilotage and charts Buoys and markers Lights
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Pilotage Mark Powell Mole Valley Sub Aqua Club SAA - 101
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
Outline • Pilotage and charts • Buoys and markers • Lights • Leading lines and lights • Natural pilotage features
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 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
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
Starboard markers Port markers 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
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 tide
Direction of Rising Tide Some places are confusing : • Split Estuaries: Solent • East coast estuaries Direction of Buoyage symbol highlights the direction
Cardinal Markers “Safe water to the west” • 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.
White, VQ or Q Q(9) ev. 15 sec. or,VQ (9) ev. 10 sec. Q (3) ev. 10 sec. or,VQ (3) ev. 5 sec. Q (6) + long fl. ev. 15s.,VQ (6) + long fl. ev. 10s. All four Cardinal Markers N Danger W E S
Safe Water Marker • Indicate start of deep water • Round top mark • Red and white colour • May have a white Isophase or Occulting light
Isolated Danger Marker • Indicate a hazard • Two round top marks • Red and black colour • May have a White, Group Flashing 2 light
Special Markers Showboundary of administrative area Speed limit, swimming, anchoring May have a cross top mark Yellow colour May have a yellow light
Sample Characteristic Sample Symbol Gp Oc(3).10s 15m 10M Visible for 10 Miles 15m above MHWS Group occulting 3 Every 10 seconds MHWS Sea level Light symbols & characteristics
Description Characteristic Chart Abbreviation Alternating Fixed Alt. R.W.G. F. 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) Light characteristics
Lt Lt Ho Oc.R.4s 10M Fl.R Fl.R Fl.G Fl.G VQ(3)5s VQ(6)+L.Fl10s Iso G.Fl(2) Fl.Y Chart symbols for buoys and lights • Major light, minor light, light, light house Lateral buoys and marks Cardinal buoys and marks Safe water buoys and marks Isolated danger buoys and marks Special buoys and marks
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
084o 080o 090o 070o 100o Leading lines
356o 350o 000o 340o 010o Leading 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
Summary • Pilotage and charts • Buoys and markers • Lights • Leading lines and lights • Natural pilotage features
Iso Occ F. Gp.Fl 235o F Alt R.W.G 8M Fl W 15s 30m 10M 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? What do these chart symbols indicate?