Britain's Waterways - horsepower to transport barges and narrowboats

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Horsepower
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Horsepower
Some aero-engines are equivalent to 2000 horsepower, but when canals were first designed, both Smeaton and Telford famously worked out that the power of a real horse depended very much on how it was applied. They found that eight packhorses were needed to carry one ton, a cart horse could pull two tons but a boatman's horse could haul over fifteen times as much. A 'payload' up to 30 tons along a waterway was common, which meant that one narrowboat was equivalent to 250 packhorses.

horse towing boats

Engineering for horses
Boats should go along a canal. A perfect pull is only possible directly down the middle of the canal, but in practice the boat tends to move towards the towpath where the horse is. The nearest a horse can get to a direct pull is to be as far ahead of the boat as possible. Power transfer was therefore through a rope of huge length, generally of cotton.
A horse would not give a continuously steady pull and when he eased off, unless boatmen were lucky or careful, the rope collapsed into a tangled skein. All canal engineers knew this. Many construction details that can still be seen on today's canals are a particular shape because of the help the boatman and his horse needed.

Snagging of towropes
If a long rope suddenly caught on anything, tree stump, rough stone, bridge arch or hand-rail ...... it spelt disaster for the boat, its cargo and sometimes killed the horse by jerking him into the water.
Long ropes would tend to cut sharp corners, for example where the canal suddenly widened after a bridge or at a junction between canals. Vertical rollers were sometimes erected to ease the passage of the rope. (as in the picture on the left). At other bridge holes this was not done, and the wet towrope, full of stone dust from the towpath, wore deep notches in the brickwork arch.
Sometimes, a 'smooth' cast iron angle might be bolted to protect the arch, and although iron is more resistant to abrasion from rope, the enormous tension still left deep scars (as in the silhouette on the right).
rope marks in stone Engineers built bridges with smooth parapets of rounded coping stones or bull-nosed bricks. Any handrails or walls that came between the boat and horse, were tapered away into the ground to eliminate snagging (as in the picture on the left).

Boats don't have brakes
To slow down or stop, you cannot put a horse into reverse. Wooden bollards are the answer. The cotton tow-rope is given one or two loose turns around a bank side post and then pulled tight. Friction between the wood and rope can act to slow up to 30 tons weight of boat as it runs past, resulting in posts with sculpted waistlines, the remains of which can be seen all around the system.

A video of this, and other skills in working horsedrawn boats, is available from the Friends of the National Waterways Museum Tel: 01453 318054.

Quiet travel on horsedrawn trip boats
Foxton Vixen Tel: 0116 279 2285
Guide Bridge Maria Tel: 0160 320 8338
Godalming Iona Tel: 01483 414938
Hebden Bridge Sara Siddons Tel: 01422 845557
Llanfrynach Dragons Tail Tel: 01874 665382
Llangollen William Jessop, James Brindley Tel: 01978 860702
Newbury Kennet Valley Tel: 01635 441154
Tiverton Tivertonian Tel: 01884 253345