SLHS Narrowboat Design & Construction

More Information

1. How A Lock Works:             YT: STEM
   

2. Glossary of boating terms:  BraunstonMarina

Design Criteria

In the UK before proper roads were built, and railways had been invented, industrialisation was hampered by a transport problem. The industrialists cried out for reliable means of getting their goods from A to B.

Farmers had long used a horse and cart but on the roads of the day, in wet weather, this was not an option. Besides carts were limited to 1½ tons at best. Ships could move one hundred times this but estuaries were not where manufacturing took place -coal isn’t found near rivers.

Thus water transport had to come inland. It was to be the age of canals and they were to have but one commercial aim: to move heavy and/or bulky goods around the country. At the start there needed to be little new technology. The farmers supplied horses and feed. Shipbuilding was a national pastime and Archimedes had invented the means of going up or down a hill: the lock.

To speed up the construction of canals and use up the minimum amount of farmers’ land the canals were not built very wide. The decision was taken to build the locks to a 7’ standard. Thus barges were forced to be limited to 6’10” beam (width). In order to carry a good load they therefore had to be long. On most canals this limit was 70’. Thus the barges became known as narrowboats. Being this long mean that their cross-section was small compared to their size and so they were actually very efficient. A total of one horse-power could move 35 tons. For comparison a small car today may weigh ⅔ ton with a 60hp engine. The majority of our cars these days are even less efficient designs.

Onboard a tiny amount of accommodation was provided for the boatman reserving the largest area for the cargo. To protect it from the weather it was covered in tarpaulin.

Trading by canal, even by todays standards, was enormous. Even small canals could see 30,000 tons of cargo moved per year. In 1838 the Stratford Canal carried 180,000 tons of cargo. In 1890 the Rochdale Canal, a mere 32 miles long, saw 700,000 tons transported. Thus boat making became a huge competitive trade in itself. To keep on top of the competition designs were continuously improved. However an industrialist wanting his goods to be carried needed to know the limits of what could fit on one narrowboat so the layout became fairly standardised (see right).

● These items have aspects that uniquely contribute to national or world history.

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A modern narrowboat has all mod cons.

Narrowboat Design

Above is an example of the last  timber narrowboat to be constructed, The Roger.  It was built by Bushell Brothers in 1936 for the Wendover Canal between Aylesbury and Tring.

Modern Narrowboats

Any product has to be fit for purpose and a modern ‘live in’ narrowboat is built for comfort and convenience without missing out on all the home comforts.

Thus hot/cold running water, flushing toilets and central heating are the norm. Unlike a cramped caravan there is a huge amount of floor space and because the floor is well below water level a good adult height. Mains electricity is provided from lead-acid batteries because weight and space is not an issue. A management system oversees their charge and advises if there has been insufficient running of the engine to keep them topped up. Solar panels are often supplied.

See below.

 ● Narrowboat Component Parts Named

Powered Narrowboats

Horses needed a lot of looking after and with the invention of the steam engine, and eventually the diesel engine, speeds could be increased. However they were never going to compete with the railways -although many tried.

A typical design might be as right. One advantage was that they could tow another boat, that was engineless, either behind or alongside, if the canal was wide enough, thus doubling the capacity for the same number of staff. This unpowered boat became known as a ‘butty’.

WARNING

It is surprisingly easy to write off a boat or at least do £1000‘s of damage (see right).

The upper lock  gate must make a good seal against both its sides and lower end. There are huge forces on this gate. The sides will displace their force, through their bricks, down the whole length of the lock but at the higher end the brickwork has to be built up within the lock chamber. This ledge or cill protrudes a couple of feet beyond the gate. It is unavoidable.

All locks will have a warning that when lowering the water level the boat must be kept behind this cill as it descends. If not one end will be held up. As the water goes down the weight of the boat will cause the lower end to be dipped under the receding water and flood into the boat causing a lot of damage to fittings and engine. It’s rare for a steel boat to break it’s back but a wooden or glass fibre craft may suffer catastrophic damage.

According the the Canals & River Trust every year someone does it. The key is to not operate locks when you are tired or at night when you may not see the reminder -or even fall in.

Don’t think that this latter doesn’t happen either.

Tiredness kills !