You're motoring into harbour keeping a front beacon lined up with a rear beacon behind it. You notice the front beacon has slipped to the LEFT of the rear one. What has happened and what do you do?

You've drifted left of the leading line — steer right to re-align them

You've drifted right of the leading line — steer right to re-align them

⚓ Pilotage: Steering by What You Can See

Out in open water you rely on the compass and GPS you met earlier in this path. But squeeze into a rocky harbour entrance or a buoyed channel and there's no time to stare at instruments — you navigate pilotage: guiding the boat by eye using fixed features ashore. The skipper's most powerful pilotage tool is the transit (called a range in North America): two fixed objects lined up one behind the other. When a church spire sits exactly in front of a headland, you are somewhere on the invisible line that passes through both — a position line far more precise than any compass bearing, because it needs no instrument and updates instantly.

Transits do two jobs. As a leading line, two marks kept in line guide you safely down the middle of a channel — many harbours build purpose-made leading lights or painted daymarks for exactly this. As a clearing line, a transit tells you which side of danger you're on: "keep the water tower left of the flagpole and you'll stay clear of the reef." The magic is motion — if the front mark drifts right of the rear mark, you've moved right of the line, so you steer left to close it back up.

Good pilotage is planned before you arrive, not improvised at the helm. Build a pilotage plan: note the transits, the sequence of buoys, conspicuous landmarks, and depth-change or bearing limits, so your eyes stay up and out of the boat. Cross-check what you see against the chart and soundings from earlier cards — a landmark only helps if it's the one you think it is.