How to navigate using paper charts

Jackie & Noel Parry
Posted September 4 2015

You should never solely rely on your electronics for navigation. Always have paper-charts as a back-up – at the very minimum. Or, like us, enjoy ‘keeping your hand in’ by navigating by chart.

Chart catalogues

These show the different charts available. These are available to look at from most chart suppliers. Selecting and ordering charts takes time and effort, ensure you set aside at least one day for this exercise.

Storing charts

We store our charts, for the area we are traversing, in the chart table. This means they are folded in half. In pencil, we write the chart name and area (lat. and long.) on the reverse for easy identification (avoids having to open each chart) and place them in order of use.

Charts for other areas are stored separately, somewhere dry and ventilated. Storing them flat is ideal, rolling up charts is to be avoided if possible, as they take up more room and can easily be damaged.

Study your charts

Before setting off, study each chart, become familiar with the entire chart that you are using and find out what all the symbols mean. Highlight shallows and dangers with a highlighter pen. When you have your route plotted, check the charts thoroughly for information pertaining to your route. Do this prior to leaving, you could be in rough weather or suffer seasickness and be unable to read during the voyage.

Notices to Mariners

Keep your charts up to date with Notices to Mariners. These are issued free, available fortnightly (in Australia) through the Hydrographic office, or weekly from the National Geospatial-Intelligence Agency (NGA) in the USA.

Electronic charts

Are fantastic, but can have errors. They are an aid to navigation and should not be completely relied upon. Use electronic charts in conjunction with paper charts. You could lose your electronic charts with a flat battery or lightning strike, but you won’t lose your paper charts this way. It is good practice to zoom in and out (viewing different scales of the chart) regularly to ensure you can view all important navigation information. If you zoom out too much some pertinent information, such as offshore rocks, could be left off the screen!

Important data to note when using paper charts includes: The depth, is it in feet or metres? (Older charts may be in fathoms.) What warnings are included? What is the compass Variation? Are there compass anomalies noted? What do they say about tides and currents? What is the scale? (If you switch charts, check whether you are now using a different scale.) This important information should also be on your electronic charts, but can be hard to find and therefore easily overlooked.

See Cruisers’ AA for more chart information, including: Chart errors (where your GPS is more accurate than your chart!); Corrections vary; Safety precaution; Measurements; Fathoms; Chart symbols; Resources; The title block on a chart; Hazards and symbols; Seabed properties.

Was this helpful?Thank Jackie & Noel Parry

Replies

Write your reply...

Please select a location