Great Loop Navigation Guide: What Charts Do You Need?

It is important to remember that planning America’s Great Loop involves more than just printing out a map with a colored line marking your route. The Great Loop passes through a lot of water, from the Atlantic Intracoastal Waterway, Gulf waterways, rivers, the Great Lakes, and Canadian canals. Different routes will require different charts, as there are different navigation issues along each route.

The Great Loop is a continuous cruising route through the eastern parts of North America. A useful overview of the route is available through GPS Nautical Charts’ America’s Great Loop map.

But for navigation purposes, a Loop map must be used as a guide to planning a route and not as a replacement for nautical charts. The required chart products will depend on the waters you plan to transit and the craft you will be using on those waters.

Start With Official Electronic Navigational Charts

For the U.S. portions of the Great Loop, the NOAA Electronic Navigational Chart, or ENC, is an important source for your charts. According to NOAA, ENCs are digital vector databases intended for marine navigation. ENCs include charted features such as depths, aids to navigation, obstructions and navigational features.

NOAA ENCs are available at no cost from the Office of Coast Survey. The ENC data from the NOAA are periodically updated, with new updates being published on weekdays. The updates can involve changes in the aids to navigation, shoals, and other charted information.

This is relevant to the Great Loop because conditions may change and there may be changes in the information used for navigation purposes. A chart that was downloaded months ago before your journey cannot be considered as permanently up-to-date.

Therefore, the chartplotter or navigation software should use updated information regarding the chart of the waters you want to travel. If it is the U.S. waterway, the NOAA ENCs will be a key source.

Atlantic and Gulf Coast Charts

Charts of the coastal portions of the Loop must cover the Atlantic and Gulf channels in detail.

These charts are more than just a means of indicating your position. They must be used to:

• Chart the locations and depths of channels
• Buoy and navigation aid locations
• Bridge and clearance information
• Locations of shoals and obstructions
• Anchorages and marinas
• Inlets and entrance ways
• Regulated or restricted areas

Do not rely on a large-scale chart just because it covers the entire area. While the map is useful for understanding the route, you need detailed charts for navigating channels, inlets, or bridges.

Great Lakes Require Detailed Lake and River Coverage

The Great Lakes area is significantly different from small inland waterways. Large open water passages will pose risks due to changing weather conditions for the Loop boat. Your charts must be sufficient to cover the entire lake, its tributaries, and entrances into the harbors.

The Canadian Hydrographic Service (CHS) provides official Canadian nautical charts and publications. The e-Navigation Portal of Canada also gives access to chart corrections, notices to mariners, navigational warnings, water levels, currents, and other navigation information.

It is especially significant since the Great Loop passes through the international border of the United States and Canada.

Canadian waters must not be considered merely an extension of the U.S. charting areas. CHS charts and publications cover Canadian waters, including the Canadian portion of the Great Lakes and St. Lawrence River.

Canadian Canal Charts Are Essential

If you choose to sail on the loop route in the Canadian waterways, it is important to have something besides the generic Great Lakes charts.

The examples of such waterways that require additional local information for navigating are the Trent-Severn Waterway and the Rideau Canal. The navigation information about the above waterways is provided by Parks Canada, whereas the CHS provides nautical charts for navigation. Parks Canada states that the visitor map for the Trent-Severn Waterway is not meant for navigation.

The purpose of a canal chart is to provide the user with information about the relation between the navigation channel, locks, bridges, approaches, and surrounding dangers. It is to be used together with the current operational information.

There are notices to mariners and chart corrections published in Canada. According to CHS, it is advisable to update the charts in order to have the current information about buoys, obstructions, and other navigation information.

Erie Canal and Inland Waterways Need Local Detail

There are other navigation considerations to keep in mind for the inland stretches of the Loop. Narrow passages, bridges, locks, variations in water level, and commercial activity may take priority over routing through open waters.

At this point, the electronic chart coverage becomes especially relevant. The commercial charting software will offer additional routing and chart display options but must be verified using current official information about navigation of the waterway.

Nevertheless, the commercial chart application should be supplementary to, and not substitute for, the official navigation information supplied by the proper authority.

There are some U.S. inland waterways that are provided with Inland Electronic Navigation Charts, or IENCs, and other information related to navigation by the U.S. Army Corps of Engineers. The information provided by USACE includes waters of the Mississippi and Illinois rivers. At the same time, USACE warns that some IENC information may have inaccuracies due to waterway changes, data sources, or chart compilation and therefore cannot be considered automatic substitutes for official chart books.

This type of information can be especially helpful for Mississippi and Illinois Waterway sections of a Loop tour.

Do You Still Need Paper Charts?

Paper charts can still have value as an alternative and planning resource, but the circumstances in the United States have definitely changed.

NOAA had moved entirely off of traditional paper and raster nautical charts by December 2024. Traditional NOAA paper charts, raster charts, and associated services are no longer available. NOAA offers the NOAA Custom Chart service, which enables users to make a printable chart out of current ENC data.

This printable chart can be valuable for planning purposes and as a source of situational awareness and as an alternative. NOAA claims that the Custom Chart service makes charts based on ENC data and that there is an option to print charts.

The important thing to remember about a printed chart is that just because it was made using official data does not mean that it will remain current indefinitely.

Build a Chart System, Not Just a Chart Collection

For a realistic navigation plan for the Great Loop, several levels of information must be integrated.

The first step is to have up-to-date electronic navigational charts that are suitable for the particular waterway and navigation device that you use. The second step is to have a backup plan in case the navigation device fails. The third step is to have the Notices to Mariners, navigation warnings, bridge, lock, and water level information available for the stretch of waterway you are navigating.

Chart symbology should also be known well. According to NOAA, U.S. Chart No. 1 is the best resource for doing this.

Final Thoughts

However, there is no one "Great Loop Chart" that covers all the requirements of a looper for navigation safety.

To create the chart coverage, it is necessary to concentrate on different sections of the itinerary: ENCs for the appropriate waters of the USA provided by NOAA; chart and publication services by Canadian Hydrographic Services for the Canadian waterways; and the navigation sources for the waterways like Trent-Severn or Rideau and USACE Inland Navigation for the waterways with the application of it.

First of all, it is necessary to update the information. NOAA regularly updates its ENC data, while Canadian authorities update the charts with the notices to mariners, navigation warnings, etc.

Thus, the Great Loop is an interesting journey which requires proper preparation for the navigation. The right approach to the charts will not give you 100% safety on the way, but will allow making the correct decision on the way due to the change of the route from the open lake to the river, from the canals to coastal waters.

Plan your Great Loop journey with confidence using GPS Nautical Charts.