A lifejacket is the one piece of safety kit nobody argues about until they have to choose one. Then the questions start. Is a buoyancy aid enough? Does France count a 50-newton one? Do I have to wear it or just carry it? When does a harness become mandatory? I have answered these for my own crew often enough that I keep a short brief taped to the back of a locker door. Here is the longer version, aimed at a visiting boat in French waters.
The four buoyancy levels, and why the number matters
Lifejackets sold in Europe are rated under the ISO 12402 standard, and the rating is a number of newtons of buoyancy. There are four levels, and the gap between them is not marketing.
A 50-newton device (ISO 12402-5) is a buoyancy aid, not a lifejacket. It keeps a conscious swimmer afloat close to shore but will not turn an unconscious person face-up. A 100-newton jacket (ISO 12402-4) is for calm, sheltered water and can turn most people the right way up. A 150-newton jacket (ISO 12402-3) is the standard offshore choice, effective in rough water and strong currents and able to right an unconscious wearer. A 275-newton jacket (ISO 12402-2) is for the hardest conditions and for crew in heavy clothing or carrying gear.
The lesson visitors most often miss: a 50-newton buoyancy aid, fine for a dinghy or a paddleboard, is not the same animal as the 150-newton lifejacket you want for a coastal passage. France, and your own common sense, distinguishes between them. For cruising offshore of a sheltered estuary, think 150 newtons as your baseline.
When France makes you wear one
France sets its rules through Division 240, the safety regulation for pleasure craft under 24 metres, and it requires a flotation device for every person aboard from the most basic category upwards, meaning even within 2 miles of a shelter. That is the carrying rule. The wearing rule is what catches people.
The skipper is responsible for deciding when lifejackets are worn, and Division 240 expects them to be worn whenever conditions demand it: heavy weather, reduced visibility, night sailing, a person working on a foredeck, a non-swimmer aboard, single-handed sailing. In practice, plenty of French skippers simply require them worn under way, full stop, and that is the habit I have adopted. An inspecting officer who comes aboard in a fresh breeze and sees the crew sitting on their lifejackets rather than wearing them will, at the very least, have a pointed word. Since the 2024 overhaul of Division 240, each person must also carry an individual light, which pairs naturally with the lifejacket for night recovery.
Whether Division 240 strictly binds your foreign-flagged boat is a genuine legal grey area, one I unpack in whether French rules apply to foreign boats. The sensible answer with lifejackets is the same as with flares and pyrotechnics in France: meet the French standard regardless, because the rule and your survival point the same way.
Harnesses and the 2024 changes
The October 2024 update to Division 240 tightened the language around harnesses and clipping on. The principle France works to is straightforward: if you are at real risk of going over the side and not getting back, you should be attached to the boat. That means a harness and tether, clipped to a strong point or a jackstay, in conditions where a man-overboard recovery would be slow or doubtful.
Many modern lifejackets are sold with an integrated harness and a D-ring, which is the neat solution for a cruising boat. If yours has one, rig jackstays from cockpit to bow on each side so the crew can move fore and aft while clipped on. The numbers that matter here are not regulatory thresholds but recovery times: in cold Channel water, an unrecovered person's useful survival window can be measured in tens of minutes, and a tether that keeps them attached to the hull changes the whole problem from "find them" to "get them back aboard".
Servicing: the trap with automatic jackets
Automatic gas-inflation lifejackets are the standard choice for cruising, and they have a maintenance need that foam jackets do not. The gas cylinder and the firing mechanism have to be in date and correctly armed. A jacket with a fired or corroded cylinder, or an expired auto-trigger, is a dead weight that will not inflate when you hit the water.
Manufacturers typically recommend a full service annually, and a self-check before each season: weigh or inspect the cylinder, confirm it is screwed home, check the trigger's date window, and look for any sign the bladder has been part-inflated and refolded badly. France does not run a national lifejacket inspection scheme, but an officer who picks up a jacket and finds a missing cylinder has found a fault, and you have found out the easy way rather than the hard way.
Foam or automatic, and which to choose
There are two broad families. Foam lifejackets are always buoyant, need no servicing beyond a visual check, and cannot fail to inflate because they are already inflated. They are bulky and warm, which is why crews resent wearing them on a hot day, and that resentment is itself a safety problem because an unworn jacket saves nobody. Automatic gas-inflation jackets are slim and comfortable enough that people actually keep them on, inflating in seconds when they hit the water or when you pull the toggle. The trade is the maintenance discipline above.
For coastal and offshore cruising I use automatic 150-newton jackets with integrated harnesses, because the comfort means they get worn, and a worn 150 beats a stowed 275 every time. I keep a couple of simple foam jackets aboard too, as spares and for guests who are nervous about gas mechanisms. Buoyancy aids of 50 newtons live with the dinghy and the paddleboards and never get counted as lifejackets for the boat itself.
Children, and the fit that actually works
A lifejacket only works if it fits. An adult jacket on a child rides up over the ears and can slip off entirely in the water. Buy to the wearer's body weight, not their age: the ISO ratings are matched to weight bands, and a child needs a jacket sized for theirs, ideally with a crotch strap and, for non-swimmers and young children, a supportive collar. Try it on, do up every strap, and lift the wearer by the shoulders of the jacket; if it rides up to their nose, it is the wrong size.
A short brief for your crew
One jacket per person, rated for the conditions, with 150 newtons as a sensible offshore default. Worn under way, and certainly worn at night, in poor visibility, in heavy weather, and by anyone on the foredeck. A harness and tether clipped to a jackstay whenever a fall overboard would be hard to recover from. Automatic jackets serviced annually and checked before each season. Children sized by weight, with crotch straps done up.
Get those right and lifejackets become the one safety topic you never have to think about again at sea. Round out the rest with the Division 240 equipment overview and make sure your radio paperwork matches, since the VHF licence and MMSI rules are the other thing a French officer asks about most.
One last thought on the foreign-flag angle. As with flares and pyrotechnics in France, the strict legal question of whether Division 240 binds a non-French boat is genuinely unsettled. But lifejackets are the item where the regulation, your insurer, your crew's families and basic sense all agree. Nobody has ever regretted carrying one lifejacket per person, rated for the water they were in, and wearing it when the wind got up. Equip to the French standard, wear them under way, and the only debate left is who left the cockpit cushions out in the rain.
Sources: ISO 12402 buoyancy levels (50N/100N/150N/275N); Division 240 (decree of October 2024, Ministere de la Mer / mer.gouv.fr); RYA lifejacket guidance (rya.org.uk).
