Why the chart table still earns its keep

A screen is brilliant at telling you where you are. It is far less good at helping you decide where you ought to be at half past four in the morning, when the wind has gone northerly, the tide is about to turn against you and the crew are asleep. That is the work of a paper chart: a large, quiet, unarguable surface you can draw on, rub out, argue with and think across.

Planning a passage on paper slows you down in the best possible way. You read the shape of the coast, notice the headland that will funnel the wind, spot the overfalls lying off the point, and see the gap between two tidal streams that has to be crossed. None of that is hidden behind a menu.

Choose the right scale before anything else

One chart will rarely do a whole passage. In UK waters a run from the Solent to Dartmouth, or from the Blackwater to Lowestoft, usually wants three or four sheets working together. Lay them out on the cabin table and think of them as a team.

• Passage chart — the whole route on one sheet, so you can see the tidal picture from end to end and judge whether the plan is realistic.
• Approach chart — headland and estuary detail, with overfalls, traffic separation schemes and the outer buoyage shown properly.
• Harbour plan — the last mile, where buoyage tightens, anchoring is decided and a mistake gets expensive.

Check the edition date in the corner and the corrections printed alongside it. A chart that has sat in a locker for five years may still be perfectly sound in deep water and quietly wrong in an entrance that has silted or been re-buoyed.

Mark the hazards with a pencil, not a highlighter

Before you draw a single track, walk the route and mark what you must avoid. Use a soft pencil and a light hand — an eraser is part of the toolkit, and next year's plan will differ from this year's.

• Overfalls and races off headlands: Portland Bill, St Alban's Head, Start Point, the Lizard, Selsey Bill, the Mull of Galloway.
• Off-lying rocks and isolated dangers that sit outside the buoyed channel and are easy to miss on a small screen.
• Traffic: the separation schemes in the Dover Strait, plus the ferry and commercial routes that cross the Irish Sea and the North Sea.
• Pot buoys and fishing gear, which the chart notes will mention even if the plotter says nothing.

A ring round each one, a scribbled note beside it, and you have built a picture of the passage that stays in your head long after you have closed the chart.

Tidal gates and the arithmetic of timing

UK coastal sailing is largely a matter of arriving at the right place at the right time. The chart shows you why: a headland with a fast stream running past it, a sound that only behaves at slack, a stretch of coast where the fair tide lasts barely three hours.

Work out where you want to be at slack water, then count backwards through the passage, allowing for your realistic speed under sail or motor. Write the times on the chart in pencil so the plan is visible at a glance.

• Portland Bill — the race runs hardest on the spring ebb; round it near slack, or stand well offshore.
• The Needles — the fair tide west through the Solent is short; miss it and you lose a couple of hours.
• Bardsey Sound and Ramsey Sound — narrow, fast and thoroughly unpleasant at the wrong state of tide.
• The Pentland Firth — springs and neaps behave quite differently; build in the option to wait.
• The Channel Islands and Alderney Race — a fair stream can carry you west at a rate that flatters your boat's log no end.

Tide tables give you heights and streams. The chart gives you the geography that turns those numbers into a plan.

Pencil in the bolt-holes

Forecasts are wrong often enough that a good plan always contains alternatives. For every leg, mark at least two places you could run to if the weather turned or the crew had had enough. On the West Country coast that might be Falmouth, Salcombe or the Yealm; on the East Coast, the Swale, the Blackwater or the approach to Wells.

Beside each one, note the things you would want to know at two in the morning: whether the entrance dries, the tidal window for access, the shelter it offers from which wind direction, and the depth you would expect at half tide. A chartplotter will give you some of that if you ask it the right question. You only build it into a plan if you have written it down.

Keep the paper plan alive once underway

At sea, use the chart to update rather than replace the screen. Take a fix each hour, plot it, and note the tide you actually got, not the one you were promised. Jot the difference in the margin — a fair stream that arrived an hour late, a wind that bent round the headland sooner than forecast. Those notes become the most valuable pilotage you will ever own.

Cross-check your plot against the electronic position if you like; the two should agree, and when they don't, that disagreement is worth understanding before you act on either. After a few seasons, a well-used chart becomes a record of your own sailing: coffee rings, pencilled times, a tiny anchor symbol off a bay you now trust.

A passage planned on paper is a passage understood. Do that work at the chart table with the kettle on, and you can hand the helm over, take your own watch, and enjoy the coast as it slides past.