The British canal system was a monumental undertaking that transformed our countryside at a time when the only other form of transport was by cart, coach or horseback, on roads that were little more than tracks.

Construction was entirely by hand, and the work was carried out by armies of ‘navigators’ – the origin of the word ‘navvies’ that we still use today.

What they left behind was a nearly nationwide infrastructure of locks, bridges, tunnels and canal side buildings that remain in place today – and continue to give pleasure to thousands of boating enthusiasts.

Locks

Locks are how canals – and boats – go up and down hill. There are a bewildering variety. Narrow locks were designed to take a single narrow boat, broad locks could fit two side by side. Some locks are as little as six feet deep, but there’s one on the Worcester and Birmingham canal that falls 14 feet. Sometimes they come in ‘staircases’, with shared gates; sometimes in ‘flights’ of up to 30, to avoid building a cutting or embankment. And in some places the locks were duplicated, allowing boats to pass through in pairs to avoid bottlenecks.

Tunnels

Some of the canal system’s most evocative moments come when you’re travelling through a tunnel. Perhaps the most difficult engineering task facing the canal builders, tunnels were usually built by laying a route across the hilltop, sinking shafts to the level of the canal, then digging in both directions from the shafts and the tunnel entrances. Often the miners who did the work got the direction slightly wrong – and early tunnels can still be found that have a slight kink in them.

Few tunnels had towpaths, so the narrow boat’s crew had to push the craft through with their feet against the walls. The horse would take a well-earned rest – walking over the top of the hill.

Bridges

the earliest canals were required by Act of Parliament not to inconvenience anyone whose land they passed over. This meant building a large number of bridges – some of which were no more than simple brick structures linking two fields. Wooden bridges were common at locks, while much grander structures were created when the canal crossed a landowner’s country estate.

Perhaps the most intriguing and attractive bridges of all are the ‘roving’ bridges that allowed the towing horse to cross the canal without the two line getting tangled up in the bridge.

Aqueducts

Aqueducts, carrying canals across valleys, are a remarkable feat of engineering – but they were disliked by the early builders because the channel had to be lined with clay to keep it watertight. Add in the weight of the water and you need a very substantial structure to support the canal. The problem was solved later by aqueducts with cast iron troughs, that could be supported on slimmer masonry pillars.

Canal Buildings

At its height, the canal system required an army of workers – toll collectors, lock keepers and lengthsmen, who carried out simple maintenance. All these people required accommodation, and their huts and cottages can still be seen everywhere on the network.

At the other end of the scale, large industrial buildings made up the fabric of the system, feeding goods and materials to the narrow boats for distribution to ports, railways and city centre wharves. Many have long since been torn down but it’s still possible to see warehouses, pump houses and even old bottle kilns close to the towpaths in certain places.