Every summer, thousands of boaters take to the waterways to explore France via its canals. These offer a peaceful playground rich in heritage, sometimes linking two rivers, crossing regions, and revealing surprising landscapes. But what characterizes the canals—whether in Brittany, the Midi, or Burgundy—are the locks. To navigate a canal, you will have to pass through these locks, which allow you to move from one pound to another.
Maneuvering a boat through a lock is no small feat, especially for beginners. It requires anticipation, preparation… and a cool head. So, I’ll give you all the keys to understand how locks work and prepare to pass through a lock safely, whether you’re on a river cruiser, a sailboat being transported by a convoy, or a canoe. (And don’t worry, my first two locks were epic…)
History of locks: from hydraulic engineering to river leisure
The first locks date back to ancient China, but it was in Europe, from the Middle Ages onwards, that they became widespread with the development of navigable canals. Locks allowed barges and commercial boats to overcome differences in water levels between two pounds, i.e., two calm sections of water at different heights.
In France, the lock network expanded significantly with the creation of major canals such as the Canal du Midi (17th century), the Nantes to Brest Canal, and the Burgundy Canal. Today, these hydraulic structures are an integral part of the river heritage, and their use has extended to tourist river navigation and water-based leisure activities.
River locks and dam locks: what are the differences?
There are several types of locks, depending on their environment and use:
River locks
The most common for boaters. They allow boats to overcome differences in water levels on canals or canalized rivers. They are often found in series on navigable waterways.
Dam locks
These are integrated into hydroelectric dams, such as the Rance Dam, or regulation dams, like the Arzal Dam at the mouth of the Vilaine in Brittany. Larger in size, they sometimes accommodate freight barges. Some are accessible to pleasure boats, others are not.
How does a lock work?
A lock is a watertight chamber bounded by two gates (upstream and downstream). It allows a boat to move up or down between two different water levels. Here’s how it works:
- The boat enters the lock: one gate is open, the other is closed.
- The gates close behind it.
- Water is let in or drained from the chamber via sluices (valves), raising or lowering the water level.
- The opposite gate opens, and the boat can continue on its way.
A maneuver can take between 10 and 30 minutes, depending on the size of the lock and the flow rate.
How to prepare before passing through a lock?
Before entering a lock, good preparation is essential. Here are the main steps:
1. Check the schedules
- Some locks are automated, others are manual or operate on fixed schedules.
- On canals managed by Voies Navigables de France (VNF), timetables are available.
- In summer, expect waiting times, especially in late morning.
2. Anticipate the maneuver
- Prepare your mooring lines and fenders.
- Assign roles on board: helmsman, crew at the bow, stern, etc.
- Turn off the VHF or any noise that could interfere with hearing the lockkeeper’s instructions.
3. Respect the order of passage
- Boats wait at a waiting quay (or “ducale”).
- The lockkeeper may allow several boats to enter at the same time: keep your distance.
Best practices for passing through a lock
Passing through a lock with peace of mind relies on simple but rigorous actions.
During entry into the lock
- Slow down on approach: maximum 3 km/h.
- Stay aligned to avoid friction.
- Wear gloves to handle the mooring lines.
Inside the lock
- Use a short, flexible mooring line to stay close to the wall.
- Do not tie the line too tightly (risk of tipping if the water level rises quickly).
- Pay attention to water turbulence (often in the center of the lock).
During ascent or descent
- Constantly adjust the tension of the mooring lines.
- Monitor the boat’s movements.
- Avoid loud conversations or sudden movements.
Exiting the lock
- Wait for the gate to be fully open.
- Exit slowly and give way to more maneuverable boats if necessary.
Summary table: key points to remember
| Step | Do | Avoid |
|---|---|---|
| Before the lock | Prepare mooring lines, check schedules | Enter without seeing the light or lockkeeper |
| Entry | Slow down, align, anticipate fenders | Enter too fast or disorganized |
| During passage | Adjust mooring lines, stay calm | Leave ropes trailing |
| Exit | Wait for the gate to fully open | Overtake another boat without agreement |
Some tips for beginner boaters
- First time? Opt for small automatic locks on calm canals (Nantes to Brest Canal, Nivernais Canal, etc.).
- In a canoe or kayak: some locks require portage. Follow the signs, get out on the bank, and carry your boat by hand.
- Solo navigation: bring gloves, a hook or gaff, and perform maneuvers upstream to avoid countercurrents.
Passing through locks is an integral part of navigating the waterways. It’s also a moment of calm, observation, and often encounter. With a little anticipation, rigor, and a few well-established reflexes, every boater can pass through these structures with complete peace of mind. Navigating then becomes a true pleasure… from one lock to the next.