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81-601: The Pocklington Canal is a broad canal which runs for 9.5 miles (15.3 km) through nine locks from the Canal Head near Pocklington in the East Riding of Yorkshire , England , to the River Derwent which it joins near East Cottingwith . Most of it lies within a designated Site of Special Scientific Interest. The first proposals to build a canal to Pocklington were made in 1765, when there were plans for

162-740: A flash lock . Pound locks were first used in China during the Song dynasty (960–1279 CE), having been pioneered by the Song politician and naval engineer Qiao Weiyue in 984. They replaced earlier double slipways that had caused trouble and are mentioned by the Chinese polymath Shen Kuo (1031–1095) in his book Dream Pool Essays (published in 1088), and fully described in the Chinese historical text Song Shi (compiled in 1345): The distance between

243-404: A river more easily navigable, or to allow a canal to cross land that is not level. Later canals used more and larger locks to allow a more direct route to be taken. A pound lock is most commonly used on canals and rivers today. A pound lock has a chamber with gates at both ends that control the level of water in the pound. In contrast, an earlier design with a single gate was known as

324-528: A broad canal for more than one boat to be in a staircase at the same time, but managing this without waste of water requires expertise. On English canals, a staircase of more than two chambers is usually staffed: the lockkeepers at Bingley (looking after both the "5-rise" and the "3-rise") ensure that there are no untoward events and that boats are moved through as speedily and efficiently as possible. Such expertise permits miracles of boat balletics: boats travelling in opposite directions can pass each other halfway up

405-642: A canal from the Humber Estuary to Wholesea, with two branches from there, one to Weighton and the other to Pocklington. Wholesea is near to the site of Sod House Lock on the Market Weighton Canal . A second assessment of the project was made two years later, and a third in 1771, but by December of that year, the plan was for the Market Weighton Canal as built, and the branch to Pocklington had been dropped completely. In 1777,

486-466: A fast build reduced overheads. The section to Hagg Bridge opened in August 1816, and the head of navigation was extended to Walbut in the following spring. Bad weather prevented Leather from completing the work by the end of 1817, and the canal eventually opened on 30 July 1818. The final cost was £32,695, the excess over the original estimate being caused by some additional works which had to be done. £2,495

567-426: A flight of locks is simply a series of locks in close-enough proximity to be identified as a single group. For many reasons, a flight of locks is preferable to the same number of locks spread more widely: crews are put ashore and picked up once, rather than multiple times; transition involves a concentrated burst of effort, rather than a continually interrupted journey; a lock keeper may be stationed to help crews through

648-480: A lock is simple. For instance, if a boat travelling downstream finds the lock already full of water: If the lock were empty, the boat would have had to wait 5 to 10 minutes while the lock was filled. For a boat travelling upstream, the process is reversed; the boat enters the empty lock, and then the chamber is filled by opening a valve that allows water to enter the chamber from the upper level. The whole operation will usually take between 10 and 20 minutes, depending on

729-537: A lock, and the position of the forward edge of the cill is usually marked on the lock side by a white line. The edge of the cill is usually curved, protruding less in the center than at the edges. In some locks, there is a piece of oak about 9 in (23 cm) thick which protects the solid part of the lock cill. On the Oxford Canal it is called a babbie; on the Grand Union Canal it is referred to as

810-467: A new plan for a canal from the River Derwent to Pocklington was considered, and approval was obtained from Lord Rockingham , but no further action was taken. Further debate occurred in 1801, when a public meeting was held at Pocklington. Some were in favour of a route to the River Ouse , but after due consideration, an engineer called Henry Eastburn was asked to make a survey of two possible routes to

891-626: A new set of bottom gates on the Top lock in 2002, and dredging of the pound above the lock by British Waterways. Further negotiation with English Nature resulted in permission to submit a bid to the Heritage Lottery Fund for completion of the restoration work. In 2014, the Waterway Recovery Group held a camp at the canal, and restored much of the towpath between Giles and Sandhill locks. Around 1 mile (1.6 km) of

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972-480: A staircase lock can be used as an emergency dry dock). To avoid these mishaps, it is usual to have the whole staircase empty before starting to descend, or full before starting to ascend, apart from the initial chamber. One striking difference in using a staircase of either type (compared with a single lock, or a flight) is the best sequence for letting boats through. In a single lock (or a flight with room for boats to pass) boats should ideally alternate in direction. In

1053-404: A staircase, however, it is quicker for a boat to follow a previous one going in the same direction. Partly for this reason staircase locks such as Grindley Brook, Foxton, Watford and Bratch are supervised by lockkeepers, at least during the main cruising season, they normally try to alternate as many boats up, followed by down as there are chambers in the flight. As with a flight, it is possible on

1134-400: A tunnel, which when descending does not become visible until the chamber is nearly empty. A pound is the level stretch of water between two locks (also known as a reach ). The cill , also spelled sill , is a narrow horizontal ledge protruding a short way into the chamber from below the upper gates. Allowing the rear of the boat to "hang" on the cill is the main danger when descending

1215-426: Is a normal top gate, and the intermediate gates are all as tall as the bottom gate). As there is no intermediate pound, a chamber can only be filled by emptying the one above, or emptied by filling the one below: thus the whole staircase has to be full of water (except for the bottom chamber) before a boat starts to ascend, or empty (except for the top chamber) before a boat starts to descend. In an "apparent" staircase

1296-443: Is only a staircase if successive lock chambers share a gate (i.e. do not have separate top and bottom gates with a pound between them). Most flights are not staircases, because each chamber is a separate lock (with its own upper and lower gates), there is a navigable pound (however short) between each pair of locks, and the locks are operated in the conventional way. However, some flights include (or consist entirely of) staircases. On

1377-586: Is popular with anglers, and the fishing rights are licensed to the York and District Amalgamation of Anglers. Restoration is ongoing and around 7 miles (11 km) of the canal had been restored by 2020. The section from the River Derwent to the Bielby Arm is navigable, and two of the remaining five locks have been renovated. Download coordinates as:   Canal lock Locks are used to make

1458-575: Is the change in water-level in the lock. The two deepest locks on the English canal system are Bath deep lock on the Kennet and Avon Canal and Tuel Lane Lock on the Rochdale Canal , which both have a rise of nearly 20 feet (6.1 m). Both locks are amalgamations of two separate locks, which were combined when the canals were restored to accommodate changes in road crossings. By comparison,

1539-881: The Bollène lock on the River Rhône has a fall of at least 23 m (75 ft), the Leerstetten, Eckersmühlen and Hilpoltstein locks on the Rhine–Main–Danube Canal have a fall of 24.67 m (80.9 ft), each and the Oskemen Lock on the Irtysh River in Kazakhstan has a drop of 42 m (138 ft). The natural extension of the flash lock , or staunch, was to provide an upper gate (or pair of gates) to form an intermediate "pound" which

1620-476: The Grand Union . Operation of a staircase is more involved than a flight. Inexperienced boaters may find operating staircase locks difficult. The key worries (apart from simply being paralysed with indecision) are either sending down more water than the lower chambers can cope with (flooding the towpath, or sending a wave along the canal) or completely emptying an intermediate chamber (although this shows that

1701-613: The Milan canal system sponsored by Francesco Sforza ) between 1452 and 1458. In Ancient Egypt, the river-locks was probably part of the Canal of the Pharaohs : Ptolemy II is credited by some for being the first to solve the problem of keeping the Nile free of salt water when his engineers invented the lock around 274/273 BC. All pound locks have three elements: The principle of operating

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1782-598: The Song dynasty (960–1279 CE). The Songshi or History of the Song Dynasty, volume 307, biography 66, records how Qiao Weiyue, a high-ranking tax administrator, was frustrated at the frequent losses incurred when his grain barges were wrecked on the West River near Huai'an in Jiangsu . The soldiers at one double slipway, he discovered, had plotted with bandits to wreck heavy imperial barges so that they could steal

1863-721: The British Waterways Board. Three sections of the canal, covering most of its route, have been designated as a Site of Special Scientific Interest , and consequently, all restoration and activity had to be by agreement between British Waterways and Natural England . Negotiations to restore Walbut lock took months to complete, but permission was finally granted in 1992. In 1995, the Pocklington Canal Amenity Society launched an appeal to fund new gates for Coates lock, and these were fitted in 2000. The section nearest to Pocklington benefited from

1944-689: The Carrapatelo and Valeira locks on the Douro river in Portugal, which are 279 feet (85 m) long and 39 feet (12 m) wide, have maximum lifts of 115 and 108 feet (35 and 33 m) respectively. The two Ardnacrusha locks near Limerick on the Shannon navigation in Ireland have a rise of 100 feet (30 m). The upper chamber rises 60 feet (18 m) and is connected to the lower chamber by

2025-466: The Chesapeake and Ohio Canal, the lockkeepers were required to remove the windlasses from all lock paddles at night, to prevent unauthorized use. A swell was caused by opening suddenly the paddle valves in the lock gates, or when emptying a lock. To help boats traveling downstream exit a lock, the locksman would sometimes open the paddles to create a swell, which would help "flush" the boat out of

2106-556: The Derwent, presumably so that goods for the Pocklington Canal would have to travel a greater distance along the Derwent, and therefore the tolls would be greater, but Leather found this route to be problematic, and proposed an alternative route to East Cottingwith. Before actually conducting the survey, he estimated the cost at £43,630, for a route with 8 locks that stopped at the turnpike road to Hull . He also suggested that

2187-402: The Derwent. Eastburn had worked for John Rennie , but his whereabouts after 1801 are unknown, and when the report was presented, it had been produced by William Chapman . He suggested two routes, an 8-mile (13 km) route from East Cottingwith and a 9.5-mile (15.3 km) one from Bubwith . He then recommended that they choose a third route, 13.5 miles (21.7 km) long, which would join

2268-463: The Earl would be building a lock on the Derwent at East Cottingwith. As he was not, an entrance lock had to be built, which had not been included in the original estimate. The canal was started from the Derwent end, so that sections could be brought into use as they were completed. Work progressed quickly, and some of the shareholders protested at the frequency with which calls were made for the money, but

2349-567: The Grand Union (Leicester) Canal, the Watford flight consists of a four-chamber staircase and three separate locks; and the Foxton flight consists entirely of two adjacent 5-chamber staircases. Where a very steep gradient has to be climbed, a lock staircase is used. There are two types of staircase, "real" and "apparent". A "real" staircase can be thought of as a "compressed" flight, where

2430-622: The Heritage Lottery Fund and £106,400 from the Inland Waterways Association . Dredging of the channel and cutting back the reeds was undertaken by the Canal and River Trust . The canal society own a trip boat called New Horizons , which is based at Melbourne , and is used to enable the public to experience a cruise on the canal during the summer months. The canal is also noted for its wide variety of fish stocks, including tench, bream, perch and roach. It

2511-487: The Ouse near Howden . Knowing that this was unlikely to meet the approval either of Lord Rockingham or of Lord Fitzwilliam, who owned the Derwent, the plan was dropped. Finally, in 1812, Earl Fitzwilliam employed George Leather Jr., to survey a proposed route. At the time, both Leather and his father were working for the Earl on a navigation and drainage scheme for the upper Derwent. The suggested route started at Sutton Lock on

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2592-752: The Protection Society was presented to the Redevelopment Advisory Committee in June 1959, when the Committee were examining a proposal to close the canal and fill it with sludge from a water treatment plant. In the 1960s consideration was given to the possibility of restoring the canal, and in 1969 the Pocklington Canal Amenity Society was formed. Restoration began in 1971 with the repair of

2673-475: The advent of canals in Britain. The sides of the turf-lock are sloping so, when full, the lock is quite wide. Consequently, this type of lock needs more water to operate than vertical-sided brick- or stone-walled locks. On British canals and waterways most turf-sided locks have been subsequently rebuilt in brick or stone, and so only a few good examples survive, such as at Garston Lock , and Monkey Marsh Lock , on

2754-536: The boat entered the lock. Pulling on the rope slowed the boat, due to the friction of the rope against the post. A rope 2 + 1 ⁄ 2 inches (6.4 cm) in diameter and about 60 feet (18 meters) long was typically used on the Erie Canal to snub a boat in a lock. One incident, which took place in June 1873 on the Chesapeake and Ohio Canal, involved the boat the Henry C. Flagg and its drunk captain. That boat

2835-471: The bottom cill at all but the higher tides – the new bottom chamber rises just far enough to get the boat over the original lock cill. In China, the recently completed Three Gorges Dam includes a double five-step staircase for large ships, and a ship lift for vessels of less than 3000 metric tons. Examples of "apparent" staircases are Foxton Locks and Watford Locks on the Leicester Branch of

2916-443: The canal could be continued into Pocklington, with an extra two locks, for an additional cost of £8,257. He calculated the probable revenue at £1,245.50 per year, which was surprisingly close to the actual figure once the canal was built. He started surveying in 1813, but became ill, and the work was not completed until June 1814. There was some debate as to whether the extension from the road into Pocklington should be built, but it

2997-553: The canal provides habitat. In late July 2018 the section of canal between the Melbourne Arm and the Bielby Arm was re-opened to navigation, exactly 200 years after the original opening of the canal. Restoration of the swing bridge below Walbut lock was funded by a donation from the Pocklington Canal Boat Club in 2014, and the refurbishment of Walbut and Thornton locks was aided by a grant of £500,000 from

3078-468: The canal to Pocklington, while corn, flour and timber travelled in the opposite direction. Traffic rose gradually, enabling the debts to be repaid during the 1820s, and in 1830, a dividend of 3 per cent was paid to shareholders. Many of the committee who had steered the project from the beginning took the opportunity to stand down at this point, to allow younger men to take the canal forwards. Average receipts from tolls were around £1,400 per year, which allowed

3159-641: The canal would cause frequent interruptions of the heavy road traffic. It can be emptied by pumping – but as this uses a lot of electricity the method used when water supplies are adequate is to drain the lock to a nearby burn . In 2016 the Kieldrecht Lock in the Port of Antwerp in Belgium took over the title of the world's largest lock from the Berendrecht Lock in the same port and still has

3240-518: The canal, as well as the Market Weighton Canal, the Leven Canal and Vavasour's Canal. The total cost to the railway for the canal was £17,980, of which £4,587 was paid in cash and went to the smaller shareholders, while the rest was paid to the larger shareholders as debentures . The purchase was completed on 18 November 1848, and the railway had an obligation to keep the canal open. The Railway Commissioners could intervene if they failed to maintain

3321-426: The canal. To minimise costs little more than token maintenance was carried out by the railway company. In May 1850, Swann, who had been collecting tolls since the canal opened, was dismissed. Some of the locks were repaired in 1851, after which the railway company received a suggestion from landowners that the canal should become a drainage ditch, with a tramway running along the bank for the carriage of goods. Although

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3402-544: The chambers so that some water from the emptying chamber helps to fill the other. This facility has long been withdrawn on the English canals, although the disused paddle gear can sometimes be seen, as at Hillmorton on the Oxford Canal . Elsewhere they are still in use; a pair of twinned locks was opened in 2014 on the Dortmund–Ems Canal near Münster , Germany. The once-famous staircase at Lockport, New York ,

3483-631: The chambers still have common gates, but the water does not pass directly from one chamber to the next, going instead via side ponds. This means it is not necessary to ensure that the flight is full or empty before starting. Examples of famous "real" staircases in England are Bingley and Grindley Brook . Two-rise staircases are more common: Snakeholme Lock and Struncheon Hill Lock on the Driffield Navigation were converted to staircase locks after low water levels hindered navigation over

3564-404: The chance of a boat finding a lock set in its favour. There can also be water savings: the locks may be of different sizes, so that a small boat does not need to empty a large lock; or each lock may be able to act as a side pond (water-saving basin) for the other. In this latter case, the word used is usually "twinned": here indicating the possibility of saving water by synchronising the operation of

3645-559: The cill bumper. Some canal operation authorities, primarily in the United States and Canada, call the ledge a miter sill (mitre sill in Canada). Gates are the watertight doors which seal off the chamber from the upper and lower pounds. Each end of the chamber is equipped with a gate, or pair of half-gates, traditionally made of oak or elm but now usually made of steel ). The most common arrangement, usually called miter gates ,

3726-523: The concept has been suggested in a number of cases, the only example in the world of a drop lock that has actually been constructed is at Dalmuir on the Forth and Clyde Canal in Scotland. This lock, of the single-chamber type, was incorporated during the restoration of the canal, to allow the replacement of a swing bridge (on a busy A road) by a fixed bridge, and so answer criticisms that the restoration of

3807-837: The difficulties, trade on the canal continued until 1932 and the canal remained passable for a further two years. When the railways were nationalised in 1948 the largely derelict (although not abandoned) canal became the responsibility of the British Transport Commission and from 1962 the British Waterways Board , which subsequently became British Waterways . In July 1958, the Bowes Committee published their Inquiry into Inland Waterways , which recommended that waterways should be classed as A, B or C, where class A and B would be retained for navigation, but class C would not. The Pocklington Canal

3888-511: The dividend to be around 3 per cent until the late 1840s. In 1845, the projected York & Hull East & West Junction Railway made an offer to purchase the canal, and the chairman of the Pocklington company, who was associated with the York and North Midland Railway , made a counter offer for the same amount on behalf of his railway. The canal company accepted both offers, on the basis that

3969-488: The entrance lock near East Cottingwith. In 1980, the Shell Oil Company funded a new set of gates for Thornton Lock, under an awards scheme. Further assistance was provided in 1986 when Pocklington Canal Amenity Society provided two swing bridges and East Yorkshire Borough Council funded the work to fit them. The canal as far as the Melbourne Arm was formally opened on 19 July 1987 by Brian Dice, Chief Executive of

4050-487: The first railway to be authorised by an act of Parliament could then buy the canal. The York and North Midland obtained its act in 1846 (the York and North Midland Railway East Riding Branches Act 1846), and opened a line in October 1847 which linked Beverley , Market Weighton, Pocklington and York. They obtained another act in 1847 ( the York and North Midland Railway (Canals Purchase) Act 1847 ), which authorised them to buy

4131-425: The flight quickly; and where water is in short supply, a single pump can recycle water to the top of the whole flight. The need for a flight may be determined purely by the lie of the land, but it is possible to group locks purposely into flights by using cuttings or embankments to "postpone" the height change. Examples: Caen Hill locks, Devizes . "Flight" is not synonymous with "Staircase" (see below). A set of locks

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4212-518: The form of the now-disused Écluse des Lorraines , connecting the Canal latéral à la Loire with the River Allier . A drop lock can consist of two conventional lock chambers leading to a sump pound, or a single long chamber incorporating the sump – although the term properly applies only to the second case. As the pounds at either end of the structure are at the same height, the lock can only be emptied either by allowing water to run to waste from

4293-487: The idea was well received, no further action was taken. When the York and North Midland Railway was taken over by the North Eastern Railway in 1854, the new owners of the canal followed a similar policy of low maintenance. Traffic declined, from 5,721 tons in 1858 to 901 tons in 1892, by which time most boats terminated at Melbourne, and could only be partially loaded, as the channel was badly silted. Despite

4374-414: The intermediate pounds have disappeared, and the upper gate of one lock is also the lower gate of the one above it. However, it is incorrect to use the terms staircase and flight interchangeably: because of the absence of intermediate pounds, operating a staircase is very different from operating a flight. It can be more useful to think of a staircase as a single lock with intermediate levels (the top gate

4455-403: The lock gates could be replaced and the boat removed from the lock. To economise, especially where good stone would be prohibitively expensive or difficult to obtain, composite locks were made, i.e. they were constructed using rubble or inferior stone, dressing the inside walls of the lock with wood, so as not to abrade the boats. This was done, for instance, on the Chesapeake and Ohio Canal with

4536-403: The lock. A boatsman might ask for a back swell, that is, to open and shut the paddles a few times to create some waves, to help him get off the bank where he was stuck. If boats ran aground (from being overloaded) they sometimes asked passing crews to tell the upstream lock to give them an extra heavy swell, which consisted of opening all the paddles on the lock gate, creating a surge that affected

4617-757: The locks near the Paw Paw Tunnel . and also the Chenango Canal On large modern canals, especially very large ones such as ship canals , the gates and paddles are too large to be hand operated, and are operated by hydraulic or electrical equipment. On the Caledonian Canal the lock gates were operated by man-powered capstans , one connected by chains to open the gate and another to draw it closed. By 1968 these had been replaced by hydraulic power acting through steel rams. The construction of locks (or weirs and dams) on rivers obstructs

4698-450: The locks were quite deep, with a rise of a little over 11 feet (3.4 m) each. Pocklington Beck supplies most of the water for the canal through a feeder at Canal Head. The paddle gear on the locks was fitted with fixed handles when the canal opened, but these were replaced by removable ones after incidents where the lock pounds were emptied by unauthorised people. A house was built for the lock-keeper and collector of tolls, and Mark Swann

4779-688: The new canal was low. This resulted in a sequential pair of locks, with gates pointing in opposite directions: one example was at Hall Green near Kidsgrove , where the southern terminus of the Macclesfield Canal joined the Hall Green Branch of the earlier Trent and Mersey Canal . The four gate stop lock near Kings Norton Junction, between the Stratford-upon-Avon Canal and the Worcester and Birmingham Canal

4860-416: The newly formed Pocklington Canal Company to raise £32,000 by issuing shares, and an extra £10,000 is required, either by subscriptions from the shareholders or by mortgaging the works. A management committee was elected at a shareholders meeting held on 19 June, and all the money had been pledged by 7 July. Leather acted as engineer, and his first job was to write to Earl Fitzwilliam's agent, to enquire whether

4941-402: The non-navigable section was dredged in 2017, as it was becoming choked with reeds. Some 8,000 tonnes of silt were removed by an amphibious dredger, and the nutrient-rich material was re-used on a local farm. The creation of areas of open water was expected to improve the bio-diversity of the canal corridor, for the benefit of rare aquatic plants and the 15 species of dragonfly and damsel for which

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5022-528: The passage of fish. Some fish such as lampreys, trout and salmon go upstream to spawn. Measures such as a fish ladder are often taken to counteract this. Navigation locks have also potential to be operated as fishways to provide increased access for a range of biota. Locks can be built side by side on the same waterway. This is variously called doubling , pairing , or twinning . The Panama Canal has three sets of double locks. Doubling gives advantages in speed, avoiding hold-ups at busy times and increasing

5103-469: The size of the lock and whether the water in the lock was originally set at the boat's level. Boaters approaching a lock are usually pleased to meet another boat coming towards them, because this boat will have just exited the lock on their level and therefore set the lock in their favour – saving about 5 to 10 minutes. However, this is not true for staircase locks, where it is quicker for boats to go through in convoy, and it also uses less water. The rise

5184-407: The spilled grain. In 984 Qiao installed a pair of sluice-gates two hundred and fifty feet apart, the entire structure roofed over like a building. By siting two staunch gates so close to one another, Qiao had created a short stretch of canal, effectively a pound-lock, filled from the canal above by raising individual wooden baulks in the top gate and emptied into the canal below by lowering baulks in

5265-411: The staircase by moving sideways around each other; or at peak times, one can have all the chambers full simultaneously with boats travelling in the same direction. When variable conditions meant that a higher water level in the new canal could not be guaranteed, then the older company would also build a stop lock (under its own control, with gates pointing towards its own canal) which could be closed when

5346-413: The sump to a lower stream or drain, or (less wastefully) by pumping water back up to the canal. Particularly in the two-chamber type, there would be a need for a bypass culvert, to allow water to move along the interrupted pound and so supply locks further down the canal. In the case of the single-chamber type, this can be achieved by keeping the lock full and leaving the gates open while not in use. While

5427-493: The title for largest volume. In 2022 the IJmuiden sea lock serving the Port of Amsterdam became the world's largest lock by surface area. The lock is 500 m (1,600 ft) long, 70 m (230 ft) wide and has sliding lock gates creating a usable depth of 18 m (59 ft). The size of locks cannot be compared without considering the difference in water level that they are designed to operate under. For example,

5508-400: The top gate and raising ones in the lower. A turf-sided lock is an early form of canal lock design that uses earth banks to form the lock chamber, subsequently attracting grasses and other vegetation, instead of the now more familiar and widespread brick, stone, or concrete lock wall constructions. This early lock design was most often used on river navigations in the early 18th century before

5589-462: The two locks was rather more than 50 paces, and the whole space was covered with a great roof like a shed. The gates were 'hanging gates'; when they were closed the water accumulated like a tide until the required level was reached, and then when the time came it was allowed to flow out. The water level could differ by 4 or 5 feet (1.2 or 1.5 m) at each lock and in the Grand Canal the level

5670-416: The water on the pound above sometimes causing boats to run aground. In addition, it raised the water level on the pound below, causing some boats to strike bridges or get stuck. On horse-drawn and mule-drawn canals, snubbing posts were used to slow or stop a boat in the lock. A 200-ton boat moving at a few miles an hour could destroy the lock gate. To prevent this, a rope was wound around the snubbing post as

5751-453: The whole pound below. On the Erie Canal, some loaded boats needed a swell to get out of the lock. Particularly lumber boats, being top heavy, would list to one side and get stuck in the lock, and needed a swell to get them out. Some lockkeepers would give a swell to anyone to help them on the way, but some would ask for money for the swell. The Erie Canal management did not like swelling for two reasons. First, it used too much water lowering

5832-463: Was all that need be emptied when a boat passed through. This type of lock, called a pound lock was known in Imperial China and ancient Europe and was used by Greek engineers in the Canal of the Pharaohs under Ptolemy II (284 to 246 BC), when engineers solved the problem of overcoming the difference in height through canal locks . Pound locks were first used in medieval China during

5913-422: Was already leaking; the crew, having partially pumped the water out, entered Lock 74, moving in front of another boat. Because they failed to snub the boat, it crashed into and knocked out the downstream gates. The outrush of water from the lock caused the upstream gates to slam shut, breaking them also, and sending a cascade of water over the boat, sinking it. This suspended navigation on the canal for 48 hours until

5994-416: Was also a doubled set of locks. Five twinned locks allowed east- and west-bound boats to climb or descend the 60 feet (18 m) Niagara Escarpment , a considerable engineering feat in the nineteenth century. While Lockport today has two large steel locks, half of the old twin stair acts as an emergency spillway and can still be seen, with the original lock gates having been restored in early 2016. Loosely,

6075-405: Was appointed to the post. The house was located close to the top lock. Tolls raised just £623 in 1820, as there was competition for goods travelling to Hull, Market Weighton and York from road transport. However, in 1822 a packet boat was bought as a joint venture by several tradesmen, and a weekly service to Hull began. Traffic consisted of coal, lime, manure and general merchandise travelling up

6156-410: Was borrowed to cover the shortfall, and Leather received a warm vote of thanks from the shareholders. The canal was sized to allow keels which operated on the Derwent to use it, and so the locks were 58 feet (18 m) long by 14 feet 3 inches (4.34 m) wide. The canal rose by around 101 feet (31 m) as it travelled the 9.5 miles (15.3 km) from the Derwent to Pocklington, and so

6237-462: Was decided to include provision for it in the bill to be put before Parliament, on the understanding that it would only be built if a majority of the shareholders approved. Leather estimated the cost for the section to the road, which included eight locks, at £32,032. The plan which accompanied the bill showed an extra five locks on the extension into Pocklington. The bill became an act of Parliament ( 55 Geo. 3 . c. lv) on 25 May 1815, which authorised

6318-527: Was in class C, and the newly formed Inland Waterways Protection Society carried out a survey of it in 1959, so that they had evidence of its condition. A government White Paper followed the Bowes Report in February 1959, which recommended that an Inland Waterways Redevelopment Advisory Committee should assist schemes to regenerate canals which were no longer commercially viable. The evidence collected by

6399-412: Was invented by Leonardo da Vinci sometime around the late 15th century. On the old Erie Canal , there was a danger of injury when operating the paddles: water, on reaching a certain position, would push the paddles with a force which could tear the windlass (or handle) out of one's hands, or if one was standing in the wrong place, could knock one into the canal, leading to injuries and drownings. On

6480-456: Was raised in this way by 138 feet (42 m). In medieval Europe a sort of pound lock was built in 1373 at Vreeswijk , Netherlands. This pound lock serviced many ships at once in a large basin . Yet the first true pound lock was built in 1396 at Damme near Bruges , Belgium. The Italian Bertola da Novate (c. 1410–1475) constructed 18 pound locks on the Naviglio di Bereguardo (part of

6561-606: Was replaced in 1914 by a pair of guillotine lock gates which stopped the water flow regardless of which canal was higher. These gates have been permanently open since nationalisation. The best known example of a round lock is the Agde Round Lock on the Canal du Midi in France. This serves as a lock on the main line of the canal and allows access to the Hérault River . A second French round lock can be found in

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