Navigation Charts
Navigation Charts 101
Just like navigating on land, navigating the waters you plan to sail or cruise requires proper planning. There are several methods available for viewing your marine maps (properly referred to as "charts") online or off. The type you select should depend on your boating activities and preference. Most are based on information from National Oceanographic & Atmospheric Administration (NOAA) or other government sources. Let’s talk through the types.
A chart’s scale indicates its level of detail.
When choosing a navigation chart, the map’s scale will determine the level of detail the map shows. Small scale charts, like sailing charts, provide the broadest view with the least detail and are used for charting long passages. Larger scale charts, like general charts, offer greater detail. While they are good for planning a coastal cruise, they don’t offer the level of detail needed for sailing close to shore or into port. Harbor charts offer the finest detail, which enables you to plan for sailing into port.
What are "soundings"?
Water depths listed on navigational charts, which are referred to as "soundings", are based on low water levels. This ensures you have the most conservative estimate for depth when making anchor or boating in shallow waters.
Paper Navigation Charts
Paper charts are great as a course planning tool or as a backup to digital charts. Choose from traditional rolled charts or print-on-demand navigation charts that are printed at West Marine before shipping to you. Multiple charts that cover a specific region can be purchased in a regional "chart book". Chart books are popular for navigation, but like other paper charts, they must be periodically updated manually with the most current information. Print-on-demand provides fresh detail right before you embark.
West Marine offers paper navigational charts printed on uncoated paper. Choices also include waterproof charts printed on special coated paper. There are also weatherproof cases and bags available to keep standard paper from getting damaged by water.
No matter what style you choose, it is wise to have a hard-copy navigation chart onboard your boat as a back-up to digital versions.
For more about paper charts, read our West Advisor article Selecting Paper Charts.
Electronic Marine Navigation
For real-time positional accuracy without the hassle of dealing with many different paper charts to show varying layers of detail, electronic navigation systems are the way to go. Electronic navigation charts can be viewed on a smartphone, computer or chartplotter. A waterproof chartplotter with a daylight-viewable screen is a great choice for boats with exposed cockpits, while using a laptop or PC is possible in the dry interiors of larger boats.
You’ll want to be sure that whatever electronic chart you purchase is compatible with your chartplotter or the software you employ. Make a note to update your electronic charts often, to ensure that you have the latest navigational information for wherever you use your boat.
For more on electronic cartography, read our West Advisor article Selecting Electronic Cartography.