How to Read a Nautical Map

Nautical charts are road maps for the water.

Just as surface maps provide drivers with guidance and directions, nautical charts provide the same information for boaters. Nautical charts also detail unseen hazards below the water line and known routes for traffic (larger vessels) to avoid on rivers and oceans. Reading a nautical chart is an essential skill for sailors of any skill level and vessel size. All U.S. nautical charts are maintained currently by the National Geodetic Survey, which is part of the National Oceanic and Atmospheric Administration (NOAA).

Instructions

1. Obtain the most recent charts for the waterways you will navigate. Sporting goods stores and most marinas will have these available. For larger bodies of water, like rivers and oceans, this information is available through NOAA and the U.S. Coast Guard. A valuable companion tool for any chart is the National Ocean Service's (NOS) Chart No. 1 booklet. This small book provides detailed information on nautical charts' abbreviations, symbols and terms.

2. Read the chart's legend (explanation of symbols and signs) thoroughly before attempting navigation. Understand what a cone-shaped red buoy represents. They are generally used to mark the entrance to a channel, are always navigated to the starboard side of the channel, and are often lighted for nighttime navigation.

3. Orient yourself on the water according to your position on the chart before proceeding. Knowing where you are and in which direction you are heading is crucial to boating safely.

4. Note the depth of the water on which you intend to sail. This information is found all over the chart, measured in feet, written in black and numerical. Make sure the area you sail in is deep enough for your boat to pass safely through without raking (touching bottom).

5. Follow the ship's progress on the chart by identifying land masses and navigational markers placed on the water or the shoreline. Pay attention to submerged and partially submerged objects -- natural and man made and marked on the chart with universal symbols -- which may interfere with your ability to navigate safely.

Tips & Warnings

• Always check the weather first before going out onto the water.

• Do not venture into unfamiliar areas unless you have thoroughly studied the nautical charts and are comfortable with your seamanship.

References

• Boat Safe: How to Use Nautical Charts
• Boat US: Chart Reading
• School of Sailing: Unlocking the Chart

Resources

• NOAA: Charting