Shom Z Nautical Chart – Exercise Area Chart

Introduction

The Shom Z nautical chart, also known as a Zonex chart, is a specialized paper nautical chart used to identify exercise and firing areas used by maritime forces. It contains the essential cartographic information found on a standard Shom nautical chart, with an additional specific overlay showing the boundaries and designation of the areas concerned.

This information is particularly important for navigation in maritime areas where military, naval or air exercises may be conducted. Shom explains that Zonex charts make it easier to identify areas whose activation is announced through Notices to Mariners. The chart should therefore be used together with current nautical information and updates issued by Shom.

The Shom Z chart is intended for recreational sailors, commercial shipping, fishermen, navigation schools and, more generally, all navigators who need to plan a route through French maritime areas where exercise activities may take place.

What is a Shom Z or Zonex nautical chart?

A Shom Z chart is a specialized version of a Shom nautical chart. The letter “Z” added to the chart number indicates that it is a Zonex version.

Its distinctive feature is the addition of a cartographic overlay showing the boundaries and names of exercise and firing areas used by maritime forces. This representation allows the navigator to immediately locate the relevant areas on the paper chart.

The chart also retains the standard nautical information found on conventional charts:

• soundings and depths;

• depth contours;

• shoals;

• rocks and hazards;

• wrecks;

• buoys and aids to navigation;

• lights and marks;

• channels;

• ports and harbour approaches;

• anchorages;

• maritime boundaries;

• geographical information required for navigation planning.

The Zonex chart therefore adds a specific layer of information without removing the conventional elements of marine cartography.

Shom defines exercise areas as maritime areas in which military, naval or air exercises may take place. The relevant data cover, among other areas, the French metropolitan Exclusive Economic Zone.

What is a Shom Z nautical chart used for?

The primary purpose of a Shom Z chart is to facilitate the identification of areas that may be used for exercises and firing activities.

When planning a voyage, the navigator can locate these areas on the chart and incorporate this information into the route assessment.

This information can be important for:

• coastal navigation;

• offshore passages;

• cruising in Brittany;

• navigation in the Bay of Biscay;

• navigation in the Mediterranean Sea;

• fishing trips;

• vessel deliveries;

• professional route planning;

• navigation near military areas;

• passages between French ports.

A Shom Z chart does not mean that every area shown is permanently active. The navigator must check current nautical information and consult Notices to Mariners to determine the periods and conditions under which an area is activated.

The distinction between the geographical existence of an area on the chart and its actual activation is essential.

Shom Z charts and Notices to Mariners

Consulting Notices to Mariners is an important step when a planned route crosses or approaches an exercise area.

Shom states that Zonex charts allow areas whose activation is announced through Notices to Mariners to be identified easily. Charts are printed with the latest available correction at the time of production, but navigators must check that the chart is fully up to date before use.

Three separate pieces of information must therefore be distinguished:

1. the geographical presence of an exercise area on the chart;

2. the precise boundaries of that area;

3. the periods or conditions during which its activity is announced.

This procedure is particularly important for coastal and offshore navigation in military exercise areas in the Atlantic and Mediterranean.

The different types of Shom nautical charts

Shom nautical charts are available in several forms. C and L charts are the main standard nautical charts, while G and Z charts provide specialized information. Raster charts provide a digital representation of nautical charts.

Shom chart type	Support	Format	Specific information	Main use
Shom C	Paper	Flat, generally rolled in a tube	Standard nautical chart	Coastal navigation, offshore navigation and route planning
Shom L	Paper	Folded to A4	Same cartographic information as the corresponding chart	Navigation and onboard storage
Shom G	Paper	Folded to A4	Nature and distribution of seabed sediments	Sedimentology, fishing and seabed studies
Shom Z	Paper	Flat, generally rolled in a tube	Boundaries and designation of exercise and firing areas	Navigation in the relevant areas
Shom Raster	Digital	Digital file, notably GeoTIFF	Georeferenced digital reproduction of the nautical chart	Compatible navigation and charting software

Shom Z charts therefore differ from G charts: G charts provide sedimentological information, while Z charts provide information about exercise and firing areas.

Shom Z charts and navigation in Brittany

Brittany is an important area for the use of Zonex charts. The Breton coastline includes numerous areas of coastal navigation, fishing and commercial shipping.

A Shom Z chart may cover areas around Brest, the Brest approaches, Pointe Saint-Mathieu, Île Vierge, Pointe de Penmarc’h, Lorient and various other areas along the Breton coast.

Shom Z 7066Z, for example, covers the area from Île Vierge to Pointe de Penmarc’h and the approaches to Brest in the Atlantic Ocean.

For a navigator departing from Brest towards Ouessant, the Iroise Sea or southern Brittany, knowledge of exercise areas is therefore an element to be incorporated into route planning.

The ports of Brest, Douarnenez, Audierne, Concarneau, Lorient and La Rochelle may also serve as departure or arrival points for routes crossing different areas of the French Atlantic.

Shom Z charts in the Bay of Biscay

Zonex charts are also relevant for navigation in the Bay of Biscay.

The area between Brittany, the Vendée coast, Charente-Maritime, the Landes and northern Spain is a large offshore navigation area.

Shom Z 7211Z covers the Bay of Biscay from Brest to Cabo Finisterre. It therefore covers a maritime area of particular importance for routes between France and Spain.

The ports of Brest, Lorient, La Rochelle, Royan, Bordeaux, Bayonne, Bilbao, Santander and Vigo may form part of routes where knowledge of exercise areas is relevant.

For a passage across the Bay of Biscay, a Zonex chart provides an additional document allowing exercise areas to be visualized across a large maritime area.

Shom Z charts in the Mediterranean

Shom Z charts also cover several important areas of the French Mediterranean.

They include areas such as the Gulf of Lion, Provence, the French Riviera, Corsica and the Strait of Bonifacio.

Chart 7507Z covers the area from the Gulf of Lion to the Strait of Bonifacio. Other references cover Marseille, Toulon, the Îles d’Hyères, Corsica and neighboring Mediterranean areas.

The ports of Marseille, Toulon, Hyères, Saint-Tropez, Cannes, Nice, Ajaccio and Bastia are important destinations and departure points for navigation in these areas.

Shom Z 7204Z covers the area from Marseille to Elba and the Strait of Bonifacio, while charts 7406Z and 7407Z cover different sectors between Marseille, Toulon and Cavalaire-sur-Mer, as well as the Îles d’Hyères.

Zonex charts and recreational boating

The Shom Z chart is not intended exclusively for military vessels. It can also be useful to recreational sailors navigating in areas where exercises may take place.

For a sailing yacht or motorboat, the objective is to have a clear representation of the relevant areas so that a route can be planned in accordance with current nautical information.

When preparing a voyage, it is useful to:

• identify exercise areas shown on the chart;

• determine their position relative to the planned route;

• check updated nautical information;

• consult Notices to Mariners;

• check any applicable restrictions or instructions;

• consider possible route changes.

This applies both to short coastal passages and to offshore voyages.

Shom Z charts and other nautical chart publishers

Shom is the French national hydrographic service and the reference source for French maritime areas covered by its products. For international navigation, other hydrographic offices and nautical chart publishers are also widely used.

Admiralty, produced by the United Kingdom Hydrographic Office, covers the English Channel, North Sea, Irish Sea and numerous international routes.

Imray is widely used for recreational boating and cruising, particularly in the Mediterranean, Atlantic Ocean and Caribbean.

NV Charts also publishes paper and digital charts covering Europe, the Mediterranean and other cruising regions.

For a voyage from Brest through the English Channel, from La Rochelle into the Bay of Biscay, or from Marseille towards Corsica and Italy, the appropriate chart depends on the area covered, scale, type of navigation and information required.

International Admiralty, Imray or NV Charts products do not automatically replace the specific information provided by a Shom Zonex chart when navigation involves a French exercise area represented by Shom.

Format and characteristics of Shom Z charts

Shom Z charts are paper charts supplied flat and generally rolled in a tube. Depending on the chart reference, they are generally produced in A0 format or another format appropriate to the mapped area.

According to Nautic Way's product information, Z charts use 120 g/m² paper, similar to the format used for Shom C charts.

The flat format makes it easier to consult a large geographical area on a chart table.

The chart number is essential for accurately identifying the area covered. The title, scale and edition should also be checked before use.

Examples of Shom Z charts

The Zonex chart catalogue includes references covering different French maritime sectors and nearby international areas, including:

• 6951Z: Fos-sur-Mer to Capo Mele;

• 6990Z: Pointe de Penmarc’h to the Gironde estuary;

• 6991Z: Gironde estuary to Cabo Peñas;

• 7025Z: Corsica;

• 7066Z: Île Vierge to Pointe de Penmarc’h, approaches to Brest;

• 7076Z: Saint-Nazaire to Saint-Malo;

• 7204Z: Marseille to Elba and the Strait of Bonifacio;

• 7211Z: Bay of Biscay, Brest to Cabo Finisterre;

• 7406Z: Marseille to Toulon;

• 7407Z: Toulon to Cavalaire-sur-Mer and the Îles d’Hyères;

• 7507Z: Gulf of Lion to the Strait of Bonifacio.

These references demonstrate that Zonex cartography covers very different maritime areas, from the English Channel and Brittany to the Atlantic and Mediterranean.

Why use a Shom Z nautical chart?

The specific feature of the Shom Z chart is that it combines the information found on a standard nautical chart with a specific representation of exercise and firing areas.

It can be used to:

• visualize exercise-area boundaries;

• identify their designation;

• plan a route while taking their location into account;

• assess their proximity to a shipping channel or planned route;

• complement coastal or offshore route planning;

• have a paper reference for the relevant maritime area.

It is particularly useful when a planned route crosses maritime areas where military exercise activities may be scheduled.

Conclusion

The Shom Z nautical chart, or Zonex chart, is a specialized chart designed to facilitate the identification of exercise and firing areas used by maritime forces. It contains the essential information of a standard Shom nautical chart and adds a cartographic overlay showing the boundaries and designation of the relevant areas.

It is particularly useful in Brittany, the English Channel, the Bay of Biscay and the French Mediterranean, including areas around Brest, Saint-Malo, Lorient, La Rochelle, Marseille, Toulon and Corsica.

The Zonex chart must nevertheless be used together with current nautical information. The presence of an area on the chart does not necessarily mean that it is active at the time of navigation. Notices to Mariners should be consulted to verify information concerning its activation.

The Shom Z therefore provides an important complementary document for planning navigation in French maritime areas where exercise and firing activities need to be taken into account.

FAQ – Shom Z Nautical Chart

What is a Shom Z nautical chart?

A Shom Z chart is a paper nautical chart containing a specific overlay showing the boundaries and designation of exercise and firing areas used by maritime forces. It is also known as a Zonex chart.

What does Zonex mean on a Shom chart?

Zonex refers to a nautical chart variant containing specific information about exercise and firing areas. The chart number is followed by the letter Z.

What is a Shom Z chart used for?

It is primarily used to identify maritime areas where military, naval or air exercises may take place and to incorporate this information into navigation planning.

Is an area shown on a Shom Z chart always active?

No. The presence of an area on the chart indicates its location and boundaries, but its activation depends on current nautical information. Notices to Mariners should be consulted before navigation.

Should Notices to Mariners be consulted when using a Shom Z chart?

Yes. Shom explains that Zonex charts make it possible to identify areas whose activation is announced through Notices to Mariners, and navigators should check that the chart is up to date before use.

What is the difference between a Shom C chart and a Shom Z chart?

A Shom C chart is a standard nautical chart. A Shom Z chart contains the corresponding marine cartography and adds an overlay showing exercise and firing areas.

What is the difference between a Shom L chart and a Shom Z chart?

A Shom L chart is a nautical chart folded to A4 size. A Shom Z chart is a Zonex variant supplied flat and generally rolled, with a specific overlay showing exercise and firing areas.

What is the difference between a Shom G chart and a Shom Z chart?

A Shom G chart is a sedimentological chart showing the nature and distribution of seabed sediments. A Shom Z chart shows exercise and firing areas.

Where are Shom Z charts used?

They cover various areas of the English Channel, Brittany, the French Atlantic coast, the Bay of Biscay and the Mediterranean. Available chart references depend on the geographical area.

Is there a Shom Z chart for the approaches to Brest?

Yes. Shom Z 7066Z covers the area from Île Vierge to Pointe de Penmarc’h and the approaches to Brest.

Are Shom Z charts available for the Mediterranean?

Yes. Several references cover Marseille, Toulon, the Îles d’Hyères, Corsica, the Gulf of Lion and the Strait of Bonifacio.

What format is a Shom Z chart?

Shom Z charts are paper charts generally supplied flat and rolled in a tube. Depending on the reference, they are generally available in A0 format or another format suited to the mapped area.

Can a Shom Z chart be used by recreational sailors?

Yes. It can be useful to any navigator operating in an area where exercise and firing activities need to be taken into account, particularly when planning coastal or offshore routes.

Does a Shom Z chart replace other nautical documents?

No. It is a complementary cartographic document. Navigation planning must also take into account current nautical information and the documents required for the specific area and type of navigation.