Admiralty Nautical Charts – American Great Lakes

Introduction

Admiralty nautical charts of the American Great Lakes are designed for planning navigation on the five Great Lakes of North America: Lake Superior, Lake Michigan, Lake Huron, Lake Erie and Lake Ontario. These vast bodies of freshwater, shared between the United States and Canada, have specific navigational characteristics that require appropriate charting.

Published by the United Kingdom Hydrographic Office (UKHO), Admiralty charts provide a wide range of navigational information, including depths, soundings, shoals, hazards, wrecks, rocks, lights, buoys, navigation marks, channels, ports and other navigational aids.

An Admiralty nautical chart of the Great Lakes can be used to plan coastal navigation, lake crossings, navigation between the United States and Canada or port approaches. The appropriate chart reference depends on the area being navigated, the planned route and the required chart scale.

Admiralty charts for the Great Lakes

The Great Lakes form an exceptional navigable network in terms of both size and economic importance. Despite being freshwater and inland waters, their navigation conditions can in some situations resemble those encountered in a maritime environment.

The considerable distances, rapidly changing weather conditions, shoals, wrecks and numerous ports make accurate chart planning particularly important.

An Admiralty nautical chart of the Great Lakes may show:

• depths and soundings;

• depth contours and depth areas;

• shoals and hazards;

• wrecks and obstructions;

• rocks and other hazards;

• buoys and navigation marks;

• lights and navigational aids;

• navigable channels;

• ports and harbour facilities;

• anchorage areas;

• information useful for port approaches.

The chart therefore helps the navigator understand the configuration of the area and plan a route appropriate to local conditions.

The five Great Lakes

The five Great Lakes have very different configurations. The choice of an Admiralty chart therefore depends directly on the lake and geographical area being navigated.

Lake Superior

Lake Superior is the largest and westernmost of the Great Lakes. Its considerable size creates navigation conditions that can, on certain passages, resemble offshore navigation.

Charting is particularly important for identifying depths, coastal areas, ports, islands and hazards along the planned route.

Lake Michigan

Entirely within the United States, Lake Michigan has significant recreational and commercial boating activity. Its large surface area allows for coastal navigation as well as relatively long crossings.

Nautical charts can be used to plan routes along the coastline and approaches to the many ports and marinas.

Lake Huron

Lake Huron includes Georgian Bay and numerous islands. This configuration creates many areas where navigation requires detailed chart interpretation.

Channels, shoals, islands and rocky areas should be correctly identified when planning a route.

Lake Erie

Lake Erie is relatively shallow compared with the other Great Lakes and can be subject to changing weather conditions.

Navigators should pay particular attention to depths, shoals and lake conditions when planning a crossing.

Lake Ontario

Lake Ontario is the easternmost of the Great Lakes. It is connected to the St. Lawrence River and has numerous ports and navigable coastal areas.

An appropriate Admiralty chart can be used to plan coastal routes and port approaches according to the area concerned.

Navigation on the American Great Lakes

Navigation on the Great Lakes has specific characteristics associated with large inland waters.

Weather conditions can change rapidly and generate significant waves despite the absence of an open-sea environment. Winds can also produce substantial wave conditions over long distances.

Passage planning should therefore take into account:

• weather forecasts;

• available depths;

• shoals;

• obstructions and wrecks;

• ports of refuge;

• channels;

• navigational aids;

• distances between different points along the route.

Charting is therefore an essential part of preparing a passage on the Great Lakes.

Navigation between the United States and Canada

Several of the Great Lakes are shared between the United States and Canada. Navigation can therefore involve crossing an international border.

Lake Superior, Lake Huron, Lake Erie and Lake Ontario include areas under the jurisdiction of both countries. Lake Michigan, by contrast, is entirely within the United States.

For international navigation, passage planning must take into account the applicable regulations, ports of entry and any required formalities.

The nautical chart can be used to plan the route and identify the ports and channels used along the passage.

The importance of chart scale

As with all navigation, chart scale is an important consideration.

A small-scale chart provides an overview of a large geographical area. It can be useful for planning a crossing or establishing a route across the lake.

A larger-scale chart provides greater detail for coastal navigation and port approaches.

The choice therefore depends on factors such as:

• the lake being navigated;

• the distance to be covered;

• the departure port;

• the destination port;

• the planned coastal navigation;

• the level of detail required.

For a long passage, several chart scales may be required to provide appropriate coverage for each stage of the navigation.

Ports and port approaches

The Great Lakes contain numerous commercial ports, marinas and port facilities. Proper approach planning requires sufficiently detailed charting.

When approaching a port, navigators should consider:

• depths;

• channels;

• buoys;

• lights;

• obstructions;

• regulated areas;

• anchorage areas;

• port facilities.

A chart at an appropriate scale provides a clearer understanding of the immediate port environment and helps with arrival planning.

Wrecks and underwater hazards

The Great Lakes are known for their rich collection of shipwrecks. Some areas therefore contain numerous underwater obstructions that may be of interest to divers but can also represent hazards to navigation.

The representation of wrecks and other hazards on nautical charts enables navigators to identify areas requiring particular attention.

Soundings and depth information are also essential for assessing areas where under-keel clearance needs to be considered.

Example: planning a Lake Michigan crossing

Consider the example of a vessel navigating between two ports on opposite shores of Lake Michigan.

The navigator first determines the area covered by the required charting. They then identify depths, possible shoals, hazards and the main navigational references.

The route is then assessed according to the weather forecast and expected lake conditions. Ports or sheltered areas that could provide refuge can be identified along the route.

As the vessel approaches the destination port, a larger-scale chart may be required to examine the channel and access conditions in greater detail.

This example illustrates how chart planning should evolve according to the different stages of navigation.

Admiralty charts and recreational boating

Admiralty nautical charts of the Great Lakes may be useful to recreational boaters planning longer passages on inland waters.

They can be used to:

• plan a cruise;

• organise a lake crossing;

• prepare coastal navigation;

• study a port approach;

• identify hazards;

• plan a route between several ports;

• obtain an overall view of the navigated area.

Charting should always be combined with the other information required for navigation, including weather data and up-to-date navigational information.

Paper charts and passage planning

Paper charts remain a useful tool for quickly visualising a large geographical area. They can be particularly valuable when developing the overall navigation strategy before moving on to more detailed passage planning.

On the Great Lakes, where distances can be considerable, the ability to visualise a large portion of the route can be useful during planning.

A paper chart can be used to:

• plot a general route;

• identify ports;

• visualise hazards;

• plan waypoints;

• assess distances;

• prepare port approaches.

It provides a complementary planning resource alongside electronic navigation systems.

How to choose an Admiralty nautical chart of the Great Lakes

To select an appropriate chart, the first step is to identify the specific lake and geographical area concerned.

The main criteria are:

• the lake concerned;

• geographical area;

• planned route;

• chart scale;

• level of detail;

• departure and destination ports;

• type of navigation planned.

A chart intended for a Lake Superior crossing will not necessarily have the same purpose as a chart intended for the approach to a port on Lake Ontario.

Checking the geographical coverage and chart scale therefore helps ensure that the selected chart is appropriate for the planned navigation.

Who are these charts for?

Admiralty charts of the Great Lakes may meet the needs of a wide range of navigators:

• American and Canadian recreational boaters;

• sailors cruising the Great Lakes;

• sailing yacht and motorboat owners;

• navigation schools and instructors;

• maritime transport professionals;

• navigators planning lake crossings;

• crews preparing port approaches;

• navigators looking for complementary paper charting.

They can be used both for general passage planning and for detailed study of a particular area.

Conclusion

Admiralty nautical charts of the American Great Lakes provide charting suitable for navigation planning on Lake Superior, Lake Michigan, Lake Huron, Lake Erie and Lake Ontario, depending on the available chart references.

They provide information on depths, soundings, shoals, wrecks, hazards, channels, ports, buoys and navigational aids required for route planning.

Choosing an Admiralty nautical chart for the Great Lakes depends primarily on the lake concerned, the area being navigated, the planned route and the required chart scale. For a long crossing, a combination of different chart scales may be required to provide suitable charting for each stage.

Passage planning on the Great Lakes should also take into account weather conditions, lake state, available navigational information and the regulations applicable to the relevant American and Canadian areas.

FAQ – Admiralty nautical charts for the American Great Lakes

Which Admiralty nautical chart should I use for the American Great Lakes?

The choice depends on the lake, geographical area, planned route and required chart scale. Available references may cover different sections of Lake Superior, Lake Michigan, Lake Huron, Lake Erie or Lake Ontario.

What are the five Great Lakes covered by Admiralty charting?

The five Great Lakes are Lake Superior, Lake Michigan, Lake Huron, Lake Erie and Lake Ontario. Available Admiralty references should be checked according to the specific area required.

Are there Admiralty charts of Lake Michigan?

The Admiralty range includes chart references covering different areas of the Great Lakes. The reference corresponding specifically to the required area of Lake Michigan should be checked.

Do Admiralty charts cover Lake Superior?

Certain Admiralty chart references may cover areas of Lake Superior. Exact coverage depends on the selected chart reference.

Can an Admiralty chart be used for navigation between the United States and Canada?

Yes. An appropriate chart can be used to plan navigation in areas of the Great Lakes shared by the two countries. International entry requirements and applicable regulations must, however, be considered separately.

What chart scale should I choose for navigating the Great Lakes?

The scale depends on the intended use. A smaller scale is suitable for general planning of a crossing, while a larger scale is more appropriate for coastal navigation and port approaches.

Do Admiralty charts show shipwrecks in the Great Lakes?

Charts may show wrecks and other charted hazards within the areas they cover. This information is important for identifying potential underwater obstacles to navigation.

Are Admiralty nautical charts suitable for recreational boating on the Great Lakes?

They can be used to plan cruises, coastal navigation, lake crossings and port approaches, depending on the area covered and the level of detail provided by the chart.

Are the Great Lakes considered inland waters?

Yes. They are vast bodies of freshwater, but their size and weather conditions can create navigation situations comparable in some respects to conditions encountered at sea.

Is a nautical chart alone sufficient for navigating the Great Lakes?

No. The chart should be used together with relevant navigational and weather information, as well as the data and regulations applicable to the area being navigated.