A British sailor I met in La Rochelle was indignant. A maritime gendarme had come aboard, asked a few polite questions, and asked to see his charts. All he had was a chartplotter with an old Navionics card and the apps on his phone. The gendarme was not impressed, and my friend could not understand why. "It's all on the screen," he kept saying. The point he was missing is that French rules are specific about charts, they name an official source, and a screen full of apps is not automatically what the law has in mind.
So let us sort out what charts actually govern French waters, what you must carry, and how the familiar tools fit in.
SHOM is the authority
The official hydrographic body for France is SHOM, the Service Hydrographique et Oceanographique de la Marine. SHOM surveys French waters and the areas under France's cartographic responsibility, and it produces the official nautical charts and documents needed for safe navigation there. When French regulation talks about charts, it means SHOM charts, in the same way British regulation defaults to Admiralty.
SHOM publishes in three broad forms. There are paper charts, the traditional folded sheets. There are official electronic navigational charts, the ENC, the vector charts used on proper navigation systems, of which around 240 cover the French coast. And there are raster charts, essentially scanned and georeferenced images of the paper charts, sold as GeoTIFF files.
That raster product matters more than you might think, because of how it is treated legally for small craft.
What you must legally carry: Division 240
French recreational boating safety is governed by an instrument called Division 240, which sets out the equipment and documents you must carry according to how far offshore you go. The relevant categories for visitors are roughly: within 2 nautical miles of shelter, within 6 nautical miles, and the semi-offshore band from 6 to 60 nautical miles.
For semi-offshore navigation, 6 to 60 miles from a shelter, Division 240 requires you to carry, among other safety gear, the official nautical charts of the area, a summary of the international collision regulations (the RIPAM, the French rendering of the COLREGs), and a document describing the buoyage system of the area you are sailing in.
Two things to take from that. First, charts are a named legal requirement once you are more than 6 miles out, not an optional nicety. Second, the regulation specifies the official charts of the area, which brings us back to SHOM.
The good news for small-craft owners is how electronic charts are treated. For recreational vessels under 24 metres, SHOM's raster GeoTIFF charts are recognised as equivalent to paper charts and satisfy the carriage requirement. In other words you do not have to carry a locker full of paper if you carry the official SHOM raster charts on a suitable device. The regulation also accepts the collision regs and buoyage document on electronic media, provided you have the means to display them.
This is the nuance my La Rochelle friend missed. It is not that you must have paper. It is that you must have the official charts, in an accepted form, for the area you are in.
Where Navionics and the apps fit
Now the practical reality, because almost nobody navigates France purely off a SHOM paper chart any more, and that is fine.
Navionics, Garmin's chart cards, and the popular phone and tablet apps are excellent for actually getting around. They are clear, they update, they show your position live, and most experienced cruisers, myself included, do their real-time piloting on a plotter or a tablet. Nobody is going to tell you not to use them.
The question is whether they satisfy the legal carriage requirement on their own. The cleanest position, and the one that keeps a boarding officer happy, is this: use whatever app or plotter you like for navigation, but make sure that the official charts for your area are aboard in a form Division 240 accepts. For most visiting cruisers that means carrying the SHOM raster GeoTIFF charts for your cruising area on a device, and treating the commercial apps as your day-to-day working tool rather than as your proof of compliance.
I would not rely on a single phone app as my only chart provision for offshore French sailing. Phones die, fall overboard and overheat in the cockpit. Carry the official charts properly, then navigate on whatever you find easiest.
Keep them up to date, because that is a requirement too
There is a detail that catches people out. The charts you carry are supposed to be current. An out-of-date chart is not really a chart in the eyes of the rules, because buoyage, depths and hazards change. SHOM issues corrections, and the electronic products update. Make sure whatever you carry reflects a recent edition, especially for areas with shifting sands or changed buoyage. This matters as much for the official charts you carry for compliance as for the app you actually steer by.
A note on buoyage
The buoyage document Division 240 asks for is not busywork. France uses the IALA Region A system, which is the lateral system where, entering a harbour, red marks are left to port and green to starboard. This is the same convention used across most of Europe and is the opposite of the Americas. If you have crossed from the US side, or simply want it clear in your head, it is worth reading up on IALA Region A buoyage in France before you go, because getting it backwards in a tight French channel is a real hazard.
Reading depths and the tide together
One reason to favour the official SHOM charts goes beyond compliance: the chart datum, the level from which depths are measured, ties directly into the French tidal system you will be using anyway. SHOM charts reference soundings to the lowest astronomical tide, the same reference the French tide tables and the coefficient are built around. That means the depth printed on the chart and the height the tide table gives you are speaking the same language, and you can add them with confidence.
On a tidal coast that is not a small thing. A spot showing 1 metre on the chart might have 5 or 6 metres over it at a high-water spring, or be drying mud at a low-water spring. Working that out reliably depends on the chart datum and the tide prediction agreeing, which they do when both come from SHOM. If the idea of converting chart depths into real depths is new to you, the French tidal coefficient is the number that unlocks it, and it is worth pairing your chart reading with a solid grasp of how the coefficient scales the day's range.
What I actually carry
For a season cruising France my chart provision looks like this:
- The official SHOM raster GeoTIFF charts for my whole cruising area, loaded on a dedicated tablet and backed up. This covers the legal requirement.
- A chartplotter with current Navionics or equivalent cards as my primary working navigation, because it integrates with the instruments.
- A phone app as a third, independent backup, useful in the cockpit and for quick planning.
- The collision regs and a buoyage summary aboard, on paper or electronically, to complete the Division 240 list.
- A small folio of paper charts for key passages and harbours, which I keep partly out of habit and partly because paper does not run out of battery in a crisis.
That layering means I am legal, I have redundancy, and I navigate on whatever is most convenient at the time.
The bottom line
Do not make my friend's mistake of assuming that a familiar app is automatically the legal answer. France names SHOM as its chart authority, Division 240 makes official charts a carriage requirement beyond 6 miles, and the friendly way to satisfy it is to carry SHOM raster charts for your area while navigating on whatever you prefer. Get the official charts right, keep them current, and the Navionics and the apps become the pleasure they should be rather than the thing a gendarme frowns at. While you are sorting your paperwork, the same Division 240 mindset applies to your weather sources: read up on Navtex and weather broadcasts around France so your information is as official as your charts.
