Beginner to Pro: How to Read Nautical Charts

August 05, 2025

Whether you’re navigating a small bay or planning a coastal cruise, nautical charts are your roadmaps to safety and adventure. GPS and apps are great, but understanding how to read a chart turns you from a “button pusher” into a confident captain.

Here’s a step-by-step guide to go from beginner to pro.

1. Understand What a Nautical Chart Is

A nautical chart is a detailed map of waterways showing:

  • Depths (in feet, fathoms, or meters)

  • Navigational aids (buoys, lights, beacons)

  • Hazards (rocks, wrecks, shoals)

  • Channels, marinas, and anchorages

Pro Tip: Use both paper charts and electronic charts (ECS) for redundancy.

Gear Pick: Waterproof Foldable Chart – Perfect backup if electronics fail.


2. Learn to Read Depth Soundings

Numbers scattered across the chart indicate water depth.

  • Shaded blue areas = shallow water

  • White areas = deeper water

  • Tides change depths! Always check tide tables.

Rule of Thumb: Give yourself a cushion—never assume depth without factoring in low tide.

Gear Pick: Handheld Depth Finder – A great tool when approaching unknown shallows.


3. Recognize Navigation Aids

Charts use standard symbols to show Aids to Navigation (ATONs):

  • Red triangles: Red buoys or lights (keep to starboard returning from sea – “Red, Right, Returning”)

  • Green squares: Green buoys or lights (keep to port returning from sea)

  • Magenta lines: Safe navigation routes

Tip: Keep a chart symbol legend handy—new boaters can glance and learn quickly.



4. Plot Your Course

When moving from Point A to B:

  1. Identify hazards like sandbars or shoals

  2. Find safe depth channels 

  3. Mark waypoints (either on the chart or in your GPS)

  4. Check for strong currents or traffic zones

Pro Move: Use parallel rulers or a charting app to plot bearings and maintain a safe course.

Gear Pick: Marine Navigation Starter Kit – Includes parallel rulers and dividers.


5. Combine Charts with Technology

Modern boating blends tradition with tech:

  • Chartplotters show your real-time position

  • Navionics / Garmin ActiveCaptain Apps add tide, weather, and route planning

  • AIS layers show other vessels for collision avoidance

But never rely only on electronics. Charts teach you the why behind your route.


6. Practice Makes Pro

Take a short trip and challenge yourself:

  • Navigate using the chart first

  • Compare your route with GPS

  • Spot buoys and confirm their position on the chart

Within a few outings, you’ll feel like a seasoned navigator.


Final Word

Reading a nautical chart turns uncertainty into confidence. Whether you’re exploring hidden coves or planning a coastal cruise, mastering this skill will make every voyage safer—and a lot more fun.


Smooth sailing, – The BoatersNewsletter.com Crew

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