Shom Inland Waterway Charts

Introduction

Shom inland waterway charts provide official hydrographic documentation for navigation on rivers, estuaries, river mouths and areas where inland navigation connects with maritime navigation. Produced by the Service hydrographique et océanographique de la Marine, Shom charts provide detailed information on navigable channels, depths, buoyage, hazards, structures and port approaches.

The expression “Shom inland waterway chart” covers charts representing areas such as the Seine, Loire, Gironde, Charente and other French rivers and estuaries falling within the relevant hydrographic coverage. It should therefore not be interpreted as referring to one single Shom series exclusively dedicated to inland navigation. Rather, these are official nautical charts covering river and maritime-waterway environments.

This distinction is important when considering their use. Navigation on a tidal river, an estuary or an approach to a maritime port requires hydrographic documentation that is different from a general tourist map or a basic inland-waterway map.

The role of Shom in nautical charting

Shom produces nautical charts and publications required for safe navigation in the maritime areas for which France has hydrographic responsibility. Its documentation is available in both paper and electronic formats.

A Shom chart can represent many elements essential to passage planning and navigation:

• soundings and depths;

• navigable channels;

• shoals and hazards;

• wrecks;

• buoys and navigation marks;

• lights;

• leading lines;

• regulated areas;

• cables and pipelines;

• port structures;

• quays and facilities;

• bridges and infrastructure;

• anchorages;

• port and estuary approaches.

In river and estuary environments, these elements are particularly important because navigable width, available depth, currents, tides and infrastructure can strongly affect the route.

The Seine: a major maritime-waterway example

The Seine is an excellent example of the value of Shom charting in an area where maritime and inland navigation characteristics overlap.

Between Le Havre and Rouen, the river forms a major navigation route. The navigator must consider depths, channels, currents, tides, commercial traffic and numerous port facilities.

Shom chart 7419L covers the Seine between Le Havre and Rouen. It is a representative example of nautical charting for a waterway where maritime, port and inland navigation are closely interconnected.

The areas around Le Havre, Honfleur, the Seine estuary and Rouen each present different navigational conditions. Hydrographic charting must therefore provide sufficient information to identify channels and navigable areas accurately.

The Seine estuary and Bay of Seine

A river mouth is a particularly technical navigational environment. The interaction between river and seawater produces hydrographic conditions that differ from those found further upstream.

Shom charts covering the approaches to Le Havre, Antifer and the Seine estuary support the transition between navigation in the English Channel and access to the river.

In this type of environment, the navigator must consider:

• tides;

• currents;

• changes in depth;

• channels;

• commercial traffic;

• port areas;

• structures;

• buoyage;

• applicable restrictions.

The nautical chart should therefore not be regarded simply as a geographical representation. It is a fundamental tool for passage planning and navigational analysis.

The Loire and the Saint-Nazaire area

The Loire is another important example of Shom river and maritime-waterway chart coverage.

The lower river is directly connected to the Atlantic Ocean and to the port complex of Saint-Nazaire. Shom charts covering the Loire and its estuary provide hydrographic information required for navigation in this environment.

Chart 7396, dedicated to the course of the Loire, provides detailed chart coverage of a river environment. Other Shom charts cover the Loire estuary and the Saint-Nazaire port area.

This continuity is particularly useful for voyages that begin in the Atlantic, continue into the estuary and then proceed towards the inland waterway system.

The Gironde and the major Atlantic waterways

The Gironde is another important area where maritime and inland-waterway navigation are closely connected.

The estuary provides maritime access towards Bordeaux and the navigable areas associated with the Garonne and Dordogne systems. Navigation must take account of tides, currents, channels, banks and port areas.

Shom charts covering the Gironde estuary support the transition between the Atlantic Ocean and the estuarine system.

Ports such as Bordeaux, Pauillac and Blaye, together with other facilities around the estuary, demonstrate the diversity of navigational environments represented by this hydrographic documentation.

The Charente and other waterways

Shom coverage also includes areas associated with other French rivers and coastal waterways.

The mouth of the Charente is an example of an environment where navigation depends both on the configuration of the river and on its connection with the Atlantic Ocean.

Depending on the route, a Shom chart can therefore be used to prepare:

• access to a river from the sea;

• navigation through an estuary;

• a port approach;

• passage through a marked channel;

• the transition between coastal and inland waters.

This explains why charts grouped commercially under an “inland waterway” category can technically be nautical charts covering maritime-waterway environments.

Understanding the scale of a Shom inland waterway chart

Chart scale is fundamental when selecting documentation for navigation.

A small-scale chart provides an overall view of a coastline, bay or estuary. It is useful for general planning and for understanding the geographical position of a river system.

A large-scale chart provides more detail in areas where precision is essential:

• narrow channels;

• soundings;

• buoyage;

• bridges;

• quays;

• ports;

• anchorages;

• hazards;

• port installations.

In a river environment, selecting an appropriate scale is particularly important because an incorrect interpretation of channel width or hazard position can have serious consequences.

Hydrographic information and navigation

A Shom chart contains a major part of the hydrographic information required for passage planning.

The navigator can use it to identify soundings, channel configuration, buoyage, hazards, structures and regulated areas.

However, a nautical chart does not necessarily contain all the information required for a complete passage plan.

Depending on the area, it may need to be complemented by:

• sailing directions;

• light lists;

• tide tables;

• current information;

• port documentation;

• navigational warnings;

• local regulations;

• inland-waterway guides.

This complementary approach is essential for building a coherent navigational documentation set.

Professional and recreational navigation

Shom charts covering river and estuary areas may be relevant to many users:

• recreational sailors;

• motorboat owners;

• yacht crews;

• commercial fishermen;

• merchant navy officers;

• masters and skippers;

• pilots;

• port professionals;

• navigation schools;

• training centres;

• navigators planning maritime-waterway passages.

The requirements vary according to vessel type and route. A sailing yacht operating in an estuary does not face exactly the same constraints as a commercial vessel proceeding up the Seine or a workboat operating in a port environment.

Shom paper and digital charts

Shom provides its cartography in several formats.

Paper charts remain particularly useful for passage planning, work at the chart table and maintaining an overall view of the navigation area.

Digital Shom charts are available in different forms. Shom provides raster charts in GeoTIFF format as well as official vector ENC data based on the S-57 standard and distributed under the S-63 scheme.

These formats have different purposes.

A raster chart reproduces the cartographic image and preserves the visual characteristics of the paper chart. A vector ENC contains structured geographic objects such as soundings, navigation marks, wrecks and regulated areas and can be used within a compatible ECDIS environment.

Updating and maintaining chart information

Keeping nautical documentation current is a fundamental part of chart use.

Hydrographic conditions, buoyage, port infrastructure and navigation restrictions may change. Charts must therefore be used together with the applicable updating information.

Shom operates a hydrographic information production and updating system designed to incorporate relevant changes into its products.

This requirement is particularly important in estuaries and maritime-waterway areas where channels can be affected by changing hydrographic conditions.

Complementarity with Admiralty, NGA and other hydrographic services

International navigation may require documentation from several hydrographic authorities.

Shom provides the principal French hydrographic coverage for areas under French responsibility. Admiralty provides extensive international coverage, particularly for United Kingdom waters and many commercial routes. NGA complements this documentation for numerous international areas.

International hydrographic conventions provide a degree of consistency between official charting systems.

For a voyage connecting France with the English Channel, North Sea or other European countries, it is therefore appropriate to use the hydrographic documentation corresponding to each geographical area.

Planning an inland-waterway passage with a Shom chart

A systematic planning process can include several steps:

• identify the exact navigation area;

• select the chart covering the intended route;

• verify the scale;

• identify navigable channels;

• analyse depths and soundings;

• identify hazards;

• locate navigation marks;

• examine bridges and infrastructure;

• consider tides and currents where applicable;

• consult port and regulatory information;

• verify the chart's correction status;

• complement the chart with the required nautical publications.

This approach turns the chart into a genuine passage-planning instrument.

Conclusion

Shom inland waterway charts provide highly relevant hydrographic documentation for navigation on French rivers, estuaries, river mouths and maritime-waterway areas. The Seine between Le Havre and Rouen, the Seine estuary, the course of the Loire, the Saint-Nazaire area, the Gironde and the mouth of the Charente illustrate the diversity of areas concerned.

Their main characteristic is their ability to represent environments where maritime and inland navigation meet. Depths, channels, buoyage, ports, hazards, infrastructure and hydrographic conditions must be interpreted together.

For carefully planned navigation, a Shom chart is therefore a central component of nautical documentation and should be used together with the other publications and information required for the specific area.

FAQ – Shom Inland Waterway Charts

What is a Shom inland waterway chart?

It is a Shom nautical chart covering a river, river mouth, estuary or maritime-waterway area relevant to navigation.

Does Shom produce only maritime charts?

Shom is primarily the French hydrographic and oceanographic service responsible for nautical charting in the maritime areas under French responsibility. Some of its charts also cover navigable rivers, river mouths and estuaries.

Is there a Shom series dedicated exclusively to French rivers?

It is more accurate to refer to Shom charts covering river and maritime-waterway areas rather than to one single series exclusively dedicated to inland navigation.

Which Shom chart covers the Seine between Le Havre and Rouen?

Shom chart 7419L covers the Seine between Le Havre and Rouen.

Are there Shom charts covering the Loire?

Yes. Shom coverage includes charts dedicated to the course of the Loire as well as charts covering its estuary and the Saint-Nazaire area.

Does Shom cover the Gironde estuary?

Yes. Several Shom charts cover the Gironde estuary and the maritime areas providing access to the estuarine system.

Are Shom inland waterway charts suitable for professional navigation?

Yes. Charts covering river and estuary areas may be used for professional, commercial, port and training purposes, subject to the requirements applicable to the specific voyage.

What is the difference between a Shom paper chart and a Shom digital chart?

A paper chart is a printed document used, among other purposes, for work at the chart table. Digital Shom charts can include GeoTIFF raster charts and vector ENC data based on specific hydrographic standards.

Is a Shom chart sufficient to plan an inland-waterway passage?

Not necessarily. Depending on the area, it should be complemented by navigational, regulatory, port, tidal, current and other information required for safe navigation.

Do Shom charts need to be updated?

Yes. Nautical documentation must be maintained using applicable corrections and hydrographic information.

Can Shom charts be used together with Admiralty and NGA charts?

Yes. International voyages may require Shom charts to be complemented by Admiralty, NGA and other hydrographic documentation for the waters being crossed.