Module 07 · The times
When to leave when four things decide it: the window and its edges, the time of arrival leg by leg, arriving in daylight and the three clocks.
How the lesson starts
Thursday 14 March 2024: Sam takes the boat from Folkestone across the Strait to Étaples, 42.7 miles. Four things can decide when she leaves; on this day three of them set the window, and the fourth does not — which is worth seeing too.
Water to leave: Folkestone's harbour dries. Étaples' entrance: the harbour, up the Canche, is open from two hours before high water to two after, and its entrance dries, so she also needs the water over it. Daylight: the statement asks her to arrive in daylight. The stream: the crossing of the traffic scheme is her critical leg, and the stream along her track there must run with her — on this day its band is wide, and the window sits inside it.
In the exam you work every band by hand: the water off the tidal curve, the stream band from its pages, the harbour's opening from its published times, daylight from the almanac. The marker works the exact window for every ten minutes of departure and shows it in its report, so you can compare it with yours. And where the harbour at the far end dries, the water on arrival is one more band, worked like the water to leave.
On the crossing leg the bow points at right angles to the traffic (Rule 10), and the line on the chart is where the stream carries you.
Each one, a band of departure times
Each thing allows some departure times and not others. Drawn on one line of the day, each is a band.
What you practise inside
- One window
- The arrival
- Daylight
- Three clocks
- Earlier or later
This is a preview. The lesson itself is interactive: you work through it step by step, and every answer is checked as you go.