The 'modern' canal lock is a masterpiece of simplicity in lifting boats up or down inclines and locks are central to the success of Britain’s canal system. Without them, canals could not exist and any boat journey coming from the sea would end at the first incline above reach of the highest tide.
Locks allow boats to travel up and down hills. A boat wanting to travel uphill goes into an empty chamber through opened gates. Once in and the gates closed, the chamber is filled from the higher level, by the boater who carries a cranking lever to open sluices.
The lower gates are 'sealed' by the pressure of rising water at the mitre. When water levels balance the top gates open, often effortlessly or by putting a back to the beam and applying [sometimes considerable] leg effort. The boat exits to continue its journey. Going down follows the same process in reverse.
Locks allow boats to travel up and down hills. A boat wanting to travel uphill goes into an empty chamber through opened gates. Once in and the gates closed, the chamber is filled from the higher level, by the boater who carries a cranking lever to open sluices.
The lower gates are 'sealed' by the pressure of rising water at the mitre. When water levels balance the top gates open, often effortlessly or by putting a back to the beam and applying [sometimes considerable] leg effort. The boat exits to continue its journey. Going down follows the same process in reverse.
Skilled and experienced boaters are opportunists always aware of boats moving in their vicinity in either direction, knowing that a lock 'in favour' can reduce passage time by twenty minutes and halve the effort at a lock.
Narrowboats are nominally 6'10" in the beam because 'narrow' locks are nominally 7'0" wide. Hugh Malet in his "Voyage in a Bowler Hat" knew this. His "Mary Anne" had a beam of 6'6" when he made his epic Limehouse to Limerick by Liverpool trip in 1958. "Mary Anne" was only 16ft in length and began life as a Dory which had come originally from the Shetland islands.
Narrowboats are nominally 6'10" in the beam because 'narrow' locks are nominally 7'0" wide. Hugh Malet in his "Voyage in a Bowler Hat" knew this. His "Mary Anne" had a beam of 6'6" when he made his epic Limehouse to Limerick by Liverpool trip in 1958. "Mary Anne" was only 16ft in length and began life as a Dory which had come originally from the Shetland islands.
There is a positive link between Pentargon and Mitre Gates and it came from my reading Hugh Malet's escapades. At one point he had a fire on board and I don't mean to warm himself. He set Mary-Anne on fire. Partly as a result of reading "Journey in a Bowler Hat", Pentargon's front window Front Window was made watertight for tidal use. Below is a 16' Malet-sized boat rather like the Mary-Anne. Pentargon is 36'
The essential item in the design of the modern lock is the mitred lock gate. Each end is closed by a pair of wooden gates slightly too large to close flush. Their mitred edges point in the direction of the higher water level and water pressure holds them tightly together, until levels are the same either side of the gates
The earliest known lock with mitred gates in Europe was constructed in 1500 to join two canals at differing levels in Italy. Known as the "San Marco Lock" it is possible, but not provable, that Leonardo da Vinci was involved. (His notebooks reveal absorbing interest in aspects of hydraulic engineering and he was employed at that time by the Duke of Milan) ... However ... In 10th cent. China, an engineer engaged in the development of the Grand Canal, (the first cut dating to 600BC) devised a prototype which changed levels by using a chamber enclosed by movable gates between two stretches of water. It is believed that the ancient engineer 'invented' earlier versions but the first recorded gate was operational in 984.
The earliest known lock with mitred gates in Europe was constructed in 1500 to join two canals at differing levels in Italy. Known as the "San Marco Lock" it is possible, but not provable, that Leonardo da Vinci was involved. (His notebooks reveal absorbing interest in aspects of hydraulic engineering and he was employed at that time by the Duke of Milan) ... However ... In 10th cent. China, an engineer engaged in the development of the Grand Canal, (the first cut dating to 600BC) devised a prototype which changed levels by using a chamber enclosed by movable gates between two stretches of water. It is believed that the ancient engineer 'invented' earlier versions but the first recorded gate was operational in 984.
Some of the wonders of UK waterways derive from individual locks joined as a long flight or as a steep staircase – or when they appear in unusual locations maybe opening into the sea, or were built extra deep or extra wide to suit terrain.
The working lock needs no improvement; it has reached its ultimate stage of development. Its functional simplicity is its joy and every boater who sets off on a canal journey today is a time traveller, working locks in the same way as the old canal folk did in England for over two hundred years.
https://www.gavinmenzies.net/Evidence/chapter-18-grand-canals-china-and-lombardy/ (Menzies is considered unreliable)
https://www.villarevak.org/cathay/invention.html ... Look for the 10cAD! No mention of the first Chinese canals in 600BC!
The working lock needs no improvement; it has reached its ultimate stage of development. Its functional simplicity is its joy and every boater who sets off on a canal journey today is a time traveller, working locks in the same way as the old canal folk did in England for over two hundred years.
https://www.gavinmenzies.net/Evidence/chapter-18-grand-canals-china-and-lombardy/ (Menzies is considered unreliable)
https://www.villarevak.org/cathay/invention.html ... Look for the 10cAD! No mention of the first Chinese canals in 600BC!
