Here is a sentence that ruins a lot of cruising plans: you cannot refill or exchange a UK Calor bottle anywhere in France. I have watched a British couple in a Breton marina discover this the hard way, standing at a supermarket gas desk holding an empty orange Calor cylinder that the assistant, perfectly politely, could do nothing with. The good news is the workaround is simple once you understand why the systems do not talk to each other. The better news is that thinking about gas forces you to look at a system that most owners ignore until it leaks.
The reason Calor does not work here
Two reasons, and they stack.
First, exchange systems are national and closed. In the UK you swap a Calor bottle for a Calor bottle. In France the exchange brands are different, Butagaz, Antargaz, Primagaz, Finagaz and the rest, and they will only exchange their own bottles. A French dealer cannot take your Calor cylinder because it is not in their pool and they have nowhere to send it.
Second, even if you found gas, the connections differ. French bottles commonly use a 21.8 millimetre left-hand thread fitting that your UK regulator and pigtail are not built for. So it is not simply a matter of finding the right shop; the hardware on your boat assumes British bottles.
The options that actually work
You have three realistic routes, and which suits you depends on how long you are staying.
- Buy into the French system. Pay a deposit on a French bottle and exchange it locally from then on. A 13kg propane bottle bought at a supermarket like Leclerc has been reported recently at around 35 euros for the bottle deposit plus roughly 45 euros for the gas itself, with refills cheaper than the first fill since you keep swapping the same shell. You will need the matching French regulator and pigtail, a cheap chandlery item, and ideally a bottle that physically fits your gas locker, so measure before you buy.
- Run Camping Gaz. The blue Camping Gaz cylinders are sold right across Europe and exchange in France without trouble, which is why so many touring boats carry one as a backup. The catch is they come in small sizes, so they suit a light cooking load rather than a boat that also heats water on gas.
- Carry enough UK gas to last the trip. For a season on the French coast a couple of full 907 or larger UK bottles, used carefully, can see you through, and you refill back home. This is the simplest answer for a single-season visit, but plan the quantity honestly because running dry mid-cruise lands you straight back at the supermarket gas desk problem.
A fourth path some long-stay owners take is to convert to refillable LPG bottles or an underslung refillable system that you fill at an autogas pump. France has a reasonable autogas network, and a refillable bottle sidesteps the whole exchange-pool problem because you simply fill it like a car. The conversion costs more upfront, several hundred euros once you add the bottle, the filler and fitting, but it pays back over years if France becomes your base rather than a single summer. Check that your gas locker can take the refillable bottle and that the filler can be reached safely, because not every layout suits it.
If you are leaving the boat over winter, the gas question folds into the wider lay-up routine. Take the bottle ashore, isolate the system, and read the whole-boat checklist in the guide to winterising boat france so gas is not the one thing left live on an unattended boat. The same applies to the damp problem that plagues a closed-up gas locker over winter, covered in the piece on boat damp mould winter, since a corroded regulator is often a damp regulator.
The system checks that matter more than the bottle
Sorting out which bottle to buy is the easy part. The part that actually keeps you alive is the system between the bottle and the burner, and it gets neglected because it is hidden.
LPG is heavier than air. A leak does not rise and vent out of a hatch the way petrol vapour might; it sinks into the bilge and sits there, invisible, waiting. That single fact drives every safety rule that follows.
Run through this at least once a season:
- The regulator. Gas regulators have a service life and the rubber diaphragm inside perishes. Many makers recommend replacing the regulator on a fixed interval regardless of how it looks, often around every ten years, and replacing the flexible hoses well before that, since cracked or perished hose is a classic leak point. Check the date stamping on yours.
- The hoses and connections. Inspect the flexible pigtail and any rubber hose for cracking, chafe and hardening. Brush a soapy water solution onto every joint with the gas on and the appliance off, and watch for bubbles. Bubbles mean a leak. Never use a flame to test, which should not need saying but apparently does.
- The bubble tester or pressure test. Many French and European boats fit an inline bubble leak detector you can check in seconds before lighting up. If yours does not have one, a periodic professional pressure test of the whole system is cheap insurance.
- The gas locker. It must be sealed from the accommodation and drain overboard from its base, so that a leak from the bottle or regulator runs out of the boat rather than into the bilge. Make sure that drain is clear and not blocked by stowed gear.
- A gas alarm in the bilge. A sensor low down near the lowest point gives you warning of the leak you cannot smell in time. They are inexpensive and they do the one thing your nose may not.
The broader safety picture, including how the French Division 240 rules treat gas installations on a boat in their waters, is covered in the companion piece on gas safety aboard france, which is worth a read if you are planning to keep the boat here rather than just passing through.
The practical upshot
For a short visit, carry enough UK gas and do not worry about it. For a season or a base in France, buy into a French exchange brand, fit the right regulator, and keep a Camping Gaz cylinder as a get-you-home backup. And whichever bottle ends up in your locker, the bottle was never the dangerous part. The dangerous part is the ten-year-old regulator and the perished hose nobody has looked at, sitting above a bilge that would happily hold a lungful of propane. Sort the bottle in an afternoon, then spend twenty minutes with a bottle of soapy water on the bit that actually matters.
Propane or butane, and why it matters in winter
One detail that trips up British owners is the propane versus butane choice, because the two gases behave very differently in the cold. Butane stops vaporising at around zero Celsius, so a butane bottle on a January morning in Brittany simply will not deliver gas to the burner even though the bottle is half full. Propane keeps vaporising down to roughly minus 40, which is why French winter supply leans heavily on propane and why the grey-blue propane bottles are the ones you see on liveaboard boats. If you cook or heat aboard outside high summer, choose propane. The regulator pressures differ too, 37 millibar for propane against 28 to 30 for butane in the European standard, so a regulator has to match the gas, not just the bottle thread.
This is also why a boat you keep afloat through a French winter wants propane rather than the butane many UK boats carry by default. The wider afloat-winter picture, including heating loads, is set out in the guide to keeping your boat afloat winter france, and it is worth reading before you assume your existing gas setup will cope with a December cold snap on a French pontoon.
A word on appliances and certification
If you replace a cooker, a water heater or a cabin heater while you are in France, fit an appliance with a flame-failure device, the safety valve that shuts the gas off if a burner blows out. It is standard on modern marine appliances and it is the single feature that turns a momentary draught into a non-event rather than a slowly filling bilge. French marine standards expect it, and an insurer or surveyor will look for it. Have any new installation checked by a competent gas fitter rather than trusting your own plumbing, because the soap test catches leaks but only a proper installation gets the locker sealing, the drain and the appliance restraint right in the first place.
