The port de plaisance in Pouilly-en-Auxois is located in the uppermost pound of the Canal de Bourgogne. From the summit reach Wanderlust would descend at the next lock no matter her direction of travel. To the west of the port, the canal water’s drain down to the River Yonne. In Montereau-fault-Yonne the Yonne joins the Seine on the way to the Atlantic in Le Havre. To the east, in the direction we were heading, the waters of the canal connect to the River Saône. In Lyon the Saône joins the Rhone River, which deposit’s its waters into the Mediterranean near Marseille. Though the water in the summit pound would eventually make it to the Med or Atlantic, Wanderlust would not, at least not this year.
Crossing the divide between the Seine and Rhone River drainages, the Canal de Bourgogne reaches the highest point of any canal in France, 378 meters or 1240 feet above sea level. The uppermost reach could be even higher but like many summit canals, the Bourgogne incorporates a tunnel, the Souterrain de Pouilly-en-Auxois, in its highest pound.
Summit tunnels lower the elevation of the highest reach. This means that fewer locks need to be built. It also makes it easier to engineer the canal’s water supply. Delivering water to the top of the divide between river basins is a challenge; lowering the elevation of the summit pound by using a tunnel makes the engineering easier.
Until recently barges were pulled through the 3333-meter long Pouilly tunnel by a “toueur,” an electrically powered tug. The toueur propelled itself by winching in a fixed chain resting on the bottom of the canal. Towing boats using electrical power kept the exhaust fumes from building up in the tunnel. In recent years thru traffic on the Canal de Bourgogne has declined. With concerns over the build up of exhaust fumes in the tunnel reduced, the Pouilly’s toueur has been retired. The tug now sits on display on shore near Pouilly’s port de plaisance. Boats today transit the tunnel under their own power.
When it was time to leave Pouilly-en-Auxois we walked over to the nearby VNF office to let the lockkeepers know of our intent to travel through the Pouilly tunnel. The VNF gave us a radio to carry in case of an emergency. Back onboard, we pulled in the Wanderlust’s mooring ropes and headed slowly to the narrow cut that leads to the tunnel.
At the mouth of the tunnel we came to a virtual stop and drifted in slowly. Would Wanderlust fit? There was still some uncertainty, even after we made careful measurements. But after a quick survey it was clear that Wanderlust’s superstructure was in no danger of hitting the sides of the tunnel. The VNF’s practice of keeping the level of the summit pound low gave more airspace. But for Wanderlust it wasn’t really necessary. The wheelhouse would have cleared no matter the water level in the pound. On the other hand, we could see that there would have been a problem with the Wanderlust’s rear deck cover if it had not been removed. It was essential that we took it down before we departed.
There’s always a sense of amazement and annoyance when navigating the canal tunnels of France. Hidden beneath the landscape of the France countryside these long tunnels are remarkable engineering achievements. At the same time, the narrowness of the tunnels and the tendency to get sucked towards the tunnels sidewalls requires careful control of the boat. Trying to keep 4.3-meter wide Wanderlust in the center of a six-meter wide channel for an hour or two is tedious.
From a technique perspective, navigating tunnels is not particularly challenging. The challenge comes in staying focused. It is hard to concentrate on keeping the boat on the middle line of the channel for such a long time. But in the end, Wanderlust made it through unscathed.