Pilotage is navigation by eye in the last mile, with no time for chartwork. Prepare it beforehand: what you will see and which line keeps you off the rocks.
1 · The pilotage plan
Work it out before you arrive
What should go in a pilotage plan for entering a harbour?
For each leg, the heading, distance and minutes at your speed over the ground, what you will see at the turn and the danger beyond, with bearings in degrees magnetic. A pilotage plan is a card for the cockpit.
A pilotage plan is a card for the cockpit: each leg's heading, distance and minutes at your speed over the ground, what you will see at the turn and the danger beyond. Write bearings in degrees magnetic, as the compasses read; pilot books give them true, from seaward. At night use lit marks only.
If a mark fails to appear on time, you may not be where you think: stop, fix, return to the last safe point. Where chart and pilot book disagree, assume the worse; if the book warns against today's wind, go elsewhere.
One person steers; the other navigates from the cockpit, calling headings and marks. The helm repeats each heading and reports when steady.
2 · Transits and clearing lines
Lines that keep you off the danger
How does a clearing bearing keep me off a danger?
A clearing bearing is the bearing of a charted mark that just clears the danger, written NMT or NLT: a limit, not a track. While the mark's bearing stays on the safe side of it, you may tack freely.
Two charted objects in line make a transit: you are on that line whatever the plotter says. Pick objects far apart, and steer whatever heading holds them in line, bow into any cross-stream. Rear mark open (just out of line) to the left of the front one: you are left of the line, steer right.
A clearing bearing is a limit, not a track: the bearing of a charted mark that just clears the danger, written NMT (not more than) or NLT (not less than). Up to it you may tack freely. A back bearing checks a mark astern: on track it reads the reciprocal of your course; if it creeps, you are being set.
3 · Buoyage
Marks you must name at a glance
Which side do I leave a red buoy with a green band at a channel fork?
To port in region A: a lateral mark banded in the other colour, Fl(2+1), marks the preferred channel, and for the main channel you obey its main colour.
Lateral marks follow the direction of buoyage: in from the sea, or as the chart's arrow shows. Against it the sides swap. Region B reverses only the colours of lateral marks (red right returning); cardinals and all other marks are the same. A beacon stands on its danger: give it room.
Port hand, region A
Port hand, region B
At a fork, a lateral mark banded in the other colour, Fl(2+1), marks the preferred channel: for the main channel obey its main colour, so red with a green band stays to port in region A.
NorthQ · VQ
EastQ(3) 10s · VQ(3) 5s
SouthQ(6)+LFl 15s · VQ(6)+LFl 10s
WestQ(9) 15s · VQ(9) 10s
A cardinal is named for its safe side and flashes like a clock face; the long flash stops six being miscounted, and neighbours differ as Q and VQ. White Fl(2): isolated danger, under the mark. Iso, Oc, LFl 10s or Mo(A): safe water. Yellow: special mark, see the chart. Blue and yellow, Al Bu Y, racon D: new wreck.
4 · Lights and sectors
Naming a light, reading its colour
What should I do if a sectored light turns red as I come into harbour?
Come to starboard: on the way in, red usually puts you to port of the safe line. A sectored light shows white over that line, and its limits are true bearings from seaward; keep to the middle.
Time a light to name it. Oc is lit longer than dark, Iso half and half; Al changes colour on every bearing; VQ flashes twice a second. Nominal range assumes 10 miles of visibility, and a 3M pierhead light shows only close in. Against a town, stand off until both pierheads are certain: red to port, green to starboard. A narrow, half-lit entrance can wait for daylight.
A sectored light changes colour with your bearing: white over the safe line, red and green either side, or red over a danger. Limits are true bearings from seaward: convert your compass bearing. Red on the way in usually puts you to port of the line: come to starboard. The edge flickers, and at 4 miles a 3° sector is two cables wide: keep to the middle.
5 · Port and bridge signals
Lights that give orders
What do three red lights one above another at a harbour entrance mean?
Do not proceed: these are IALA port traffic signals. Three greens mean proceed, one-way; green, green, white proceed two-way; green, white, green only with orders. Three flashing reds mean a serious emergency.
IALA port traffic signals are three lights, one above another. A yellow light beside the top exempts craft that can stay outside the main channel.
Do not proceed
Proceed, one-way
Proceed, two-way
Only with orders
Three reds flashing: a serious emergency, stop or divert as told. A bridge has its own lights, given in the pilot book: commonly red and green mark the sides of the navigable span, white its centre. Ignore street lamps.
6 · Plotter and radar
Electronics are the cross-check
How do I use parallel indexing on radar for pilotage?
Lay a parallel index line along your track at the planned passing distance from a mark: its echo should slide down the line. If the echo comes inside it, turn away.
A plotter's chart can be tens of metres out and zooming adds no detail: marks in line beat the screen. Keep waypoints off the marks. 'Go to' draws a straight line from wherever you have drifted. At low speed COG wanders: steer by compass. Obey a virtual AIS mark like a buoy.
On radar a parallel index line lies along your track at the planned passing distance: the echo should slide down it; if it comes inside, turn away. A VRM ring is a clearing range; the EBL, relative when head-up, marks a turn. For fog, note an echo's range and bearing for each turn.
7 · Fog and soundings
Feeling your way in
How do I find a harbour entrance in fog without radar?
Aim off to one side of the entrance and follow a steep, even depth contour, well outside the dangers, as a handrail to a known mark: on finding the contour you know which way to turn.
In fog slow down, sound the signal, post a lookout and cross-check every aid. Without radar follow a depth contour as a handrail to a known mark: a steep, even one well outside the dangers. The sounder should read contour + tide − its own offset; less means you are inshore.
Aim off: steer deliberately to one side of the entrance, so that on finding the contour you know which way to turn. A fog signal says the mark is near, not where. Unsure of the next turn? Anchor and wait.
Practice questions
Questions from this topic, as the app asks them. Open one to see the answer.
Pilotage plan — Porto Vecchio
1 Fairway buoy → 047°M, 1.3 M
2 Fl G 3s abeam → 012°M, 0.6 M
3 Pier head → turn to port for the marina
Marina VHF 9
You are checking the pilotage plan your mate wrote for tonight's entry. What is the most useful thing to add to it?
What you will see at each turn and the danger past it
The full tidal curve for the whole day
The latitude and longitude of every mark
The opening hours of the marina office
Show the answer
A. What you will see at each turn and the danger past it
A pilotage plan is what you expect to see, when, and what lies beyond if you miss it — not data to look up.
All 100 questions of this topic are in the app: practice by topic with the reason after every answer, your mistakes brought back, and a timed mock exam. Free, no sign-up, in the browser or in Telegram.
