Yacht Sailing: Navigation, Buoys and Tides

Green or red — which buoy are you passing? The lateral system, the chartplotter as a tool, and tides explained clearly for your course.

Sport: Segeln · Level: Intermediate

Introduction

Green or red — which side of a buoy do you actually pass? The honest answer: it depends on which direction you're coming from — and in Germany a fixed system governs that. Germany uses the international buoyage system A (IALA Region A), which also applies across much of Europe. Coming from seaward, green with a conical top mark marks the starboard side of the fairway, red with a cylindrical top mark the port side.

The numbering follows the same pattern: starboard buoys carry odd numbers, port buoys even numbers. Once you've internalized that, you can read any fairway at a glance, whether in a harbor channel or the tidal flats.

The GPS chartplotter is standard kit today — but it's a tool, not a replacement for thinking. Power fails, satellite signals can drop out, and anyone who only follows the arrow on the screen loses their feel for buoys, landmarks and water depth. A paper chart and compass remain your reliable fallback.

What You Need

Step by Step

1. Understand the lateral system

Remember the basic rule: coming from seaward, green is on the right (starboard), red on the left (port). Heading back out to sea, the logic reverses accordingly — so direction of travel is always the first thing to check before you read a buoy.

2. Read top marks and numbers

Green, conical buoys with odd numbers mark starboard, red, cylindrical buoys with even numbers mark port. Rising numbers additionally tell you that you're moving inland — a useful second check when visibility is poor.

3. Use the chartplotter as a tool, not an autopilot for thinking

Use the plotter for position, course over ground and speed — but compare regularly with what you actually see: buoys, landmarks, depth on the echo sounder. That cross-check catches chart errors or GPS dropouts before they become a problem.

4. Factor in tides and current

In tidal waters, water depth changes considerably over hours, and current can make your actual course over ground diverge noticeably from your steered course. Plan passages with the current where possible instead of against it — that saves both time and fuel.

5. Plan the passage before casting off

Fix course, distance and rough passage time in advance, even for short outings. Those five minutes at the chart table save you stress on the water later — especially if the weather changes.

Common Mistakes

Safety

Never rely exclusively on a single means of navigation. GPS can fail, batteries can die, chartplotters can crash. A paper chart, a working compass and the ability to read buoys and landmarks are your insurance.

In areas with strong current or tides, your actual course over ground can differ significantly from your steered course — plan enough safety margin to shallows when passing through narrow fairways.

Pro Tip

Build yourself a simple mnemonic for the lateral system: "green-right, red-left, coming from sea" — say it out loud until it's automatic. In stressful moments with many buoys, an automated rule is worth gold.

A trick from practice: plot the planned course before casting off both on the chartplotter and roughly on the paper chart. If both match, you have double confirmation — if they diverge, you find the error ashore, not on the water.

FAQ

What do green and red buoys mean in sailing?

Germany uses buoyage system A: coming from seaward, green with a conical top mark marks the starboard side of the fairway, red with a cylindrical top mark the port side. Heading back out to sea, the assignment reverses accordingly.

Can I rely on the chartplotter alone while sailing?

Better not to. The chartplotter is a helpful tool, but GPS and electronics can fail. Check regularly against buoys, landmarks and the echo sounder, and keep a paper chart and compass aboard as a fallback.

Why do tides matter for navigation?

In tidal waters, water depth changes considerably over hours, and current can make your course over ground diverge from your steered course. Without tide knowledge you risk running aground at low water or fighting the current needlessly.

How do I know if I'm heading inland or out to sea?

Buoy numbering helps: rising numbers indicate you're moving inland. Combined with your position on the chart, that gives you a reliable second confirmation of your direction of travel.

Key Takeaways

Next guide

Yacht Sailing: Man-Overboard Maneuver

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