The first time someone mentioned "Freycinet" to me I thought they were talking about a wine region. I was sitting in a yard near Auxerre in the spring of 2022, having just bought a 12-metre steel cruiser off a retiring Dutch couple, and the surveyor asked, almost in passing, whether I knew if she was "Freycinet compatible". I did not. I nodded the way you do when you want to look competent, then went home and read everything I could find. What follows is what I wish someone had told me before I started planning a route across France.
One law from 1879 still decides where you can go
The Freycinet gauge is a set of dimensions, not a single number. It comes from a French public works law of 5 August 1879, pushed through by Charles de Freycinet, who was then minister of public works. The aim was to standardise the canal network so that one size of working barge, the classic peniche, could trade anywhere. That barge carried 300 to 350 tonnes, and the locks were built to suit it.
The result is that most of the smaller French canals share the same lock size. Once you know your boat fits, a huge chunk of the network opens up. If she does not, your map shrinks fast.
Here are the figures that matter. The maximum boat dimensions for a Freycinet canal are roughly 38.5 metres in length and 5.05 metres in beam, with a draught of about 1.8 metres. The locks themselves measure around 39 metres long by 5.2 metres wide, with a minimum water depth of about 2.2 metres over the sill. Bridges and other structures are meant to give at least 3.7 metres of air draught above the water.
Those are the textbook numbers. In practice you should treat every one of them as optimistic.
Length and beam: the easy part
Length and beam are the simplest to check because they do not change with the weather. If your boat is under 38.5 metres long and under 5 metres in the beam, the lock chamber will physically take her. Most cruising boats, hire boats and private barges sit well inside that envelope. My own 12-metre cruiser had metres to spare.
The catch is that "fits in the chamber" and "fits comfortably" are different things. A 5-metre beam in a 5.2-metre lock leaves you 10 centimetres each side if you are perfectly centred, which you never are. Add fenders and you are nudging the walls. I would not want to take anything wider than about 4.8 metres through a busy day of locks single-handed. The boats that hire companies put on these canals are usually 4 to 4.5 metres in the beam for exactly this reason.
Draught: where the trouble actually starts
Draught is the figure that catches people out. The Freycinet standard promises about 1.8 metres, and on paper a boat drawing 1.5 metres should be fine. Reality is messier. Canals silt up. After a dry summer the water level drops. Many sections, especially older or less-trafficked ones, carry far less than the nominal depth, particularly at the edges where you moor.
My honest advice: aim to draw no more than 1.4 metres if you want a relaxed time, and under 1.2 metres if you plan to wander onto the prettier, shallower canals. I have watched a 1.6-metre keel boat plough a furrow through mud for half a kilometre near a summit pound, engine screaming, while the lock-keeper shrugged. Check the current draught limits for your intended route on the VNF (Voies Navigables de France) waterway notices before you commit, not after.
If your boat is a sailing yacht with a fin keel, the canals are probably not for you without lifting the mast and accepting you will touch bottom regularly. The whole question of air draught on the French canals deserves its own read if you are mast-up.
Air draught: the bridge that ends the trip
Air draught is your height above the waterline, and it is the limit nobody thinks about until a bridge is fifty metres ahead. The Freycinet minimum is around 3.7 metres, but plenty of bridges, tunnels and fixed structures sit lower, and the figure shrinks when the canal is running high after rain.
I keep a simple rule. If anything on the boat reaches above 3.3 metres off the water, I treat it as a problem and check every structure on the route. Wheelhouses, radar arches, solar arches and aerials are the usual culprits. A folding wheelhouse roof or a tilting mast solves most of it.
How to actually check before you buy or set off
Five things I do now, in order:
- Confirm length and beam against the 38.5 by 5.05 metre envelope. This is a yes or no.
- Find your boat's real loaded draught, not the brochure figure, then knock the route limit down by 20 centimetres for silt.
- Measure air draught from the waterline to the highest fixed point, with tanks and stores aboard.
- Read the current VNF notices for your specific canals, since limits change yearly and after droughts.
- Talk to someone who has done the route that season. A spring phone call to a hire base or a marina saved me a wasted week.
Why the gauge is not the whole story
It is tempting, once you know your boat is Freycinet compatible, to assume the entire small-canal network is yours. Mostly it is, but there are wrinkles worth knowing before you plan a long route.
Not every French waterway is built to the Freycinet standard. Some of the big modern canals and the canalised rivers take far larger vessels, which is good news but irrelevant to most cruisers. More importantly, a handful of older or restored canals have locks that are slightly smaller than the nominal Freycinet figures, or that have been allowed to silt and shrink. The published dimension is the design intent, not a survey of today's reality.
Then there is the question of lock operation. A boat at the very top of the size range, close to 38 metres long, is a serious handful to manage in a 39-metre chamber, especially short-handed. If you have never worked one, my step-by-step on how a French canal lock works is worth reading before you pick the size of boat you commit to. The peniche skippers who run boats that size have decades of practice and bow thrusters. If you are a couple cruising for pleasure, you will have a far easier time well inside the envelope, and most people who live aboard happily choose boats in the 12 to 20 metre range for exactly that reason.
A word on the difference between coastal and canal thinking
If you have come off the sea, the mental shift is real. At sea you worry about draught in terms of tides and charted depths that are reasonably reliable. On the canal, draught is about silt, season and the goodwill of recent dredging, none of which appear on a chart. At sea, air draught barely crosses your mind unless you pass under a fixed bridge. On the canal, every bridge is a fixed bridge, and a wet fortnight can raise the water and steal your clearance.
The boats that thrive inland are the ones designed for it: flat-floored, shallow, modest in height, beamy enough to be comfortable but not so beamy they scrape the lock walls. A deep-keeled, tall-rigged coastal yacht can be made to do it, but she will be working against her own shape the whole way. Knowing where your boat sits against the Freycinet figures tells you, honestly, whether the canals will be a pleasure or a series of compromises.
The Freycinet gauge sounds like bureaucratic trivia until you are wedged in a lock or grounded on a summit. Get the four numbers right, build in a margin, and most of France's inland network is yours. If you are still weighing up the whole idea, the beginner's guide to the French canals is a sensible next step before you start measuring.
