Variations Lock (water navigation)

a series of photos of canadian locks in sault ste. marie illustrate drop of 22 ft (6.7 m) in lock.

variations exist types of locks , terminology used them.

single gates on narrow canals (locks approx. 7 feet or 2.1 metres wide)

on english narrow canals, upper end of chamber closed single gate full width of lock. cheaper construct , quicker operate small crew, 1 gate needs opened. these fitted post allowing rope used stop boat , close gate @ same time.
some narrow locks (e.g. on birmingham canal navigations) go further. have single gates @ lower end also. speeds passage, though single lower gates heavy (heavier single upper gate, because lower gate taller) , lock has longer (a lower gate opens lock, has pass bow or stern of enclosed boat, , single gate has wider arc 2 half-gates).
a few narrow locks imitate wide locks in having paired gates @ both ends. example bosley lock flight on macclesfield canal.


steel gates. steel gates and/or balance beams used nowadays, although all-wooden versions still fitted appropriate.

swinging gates. large steel-gated locks still can use same swinging gate design small 250-year-old locks on english canals. on english canals, steel gates have wooden mitre posts gives better seal.
sliding gates. low-head locks use sliding steel gates (see kiel canal). sliding gates of nieuwe meersluis in amsterdam double roadways.
caisson gates. kind of sliding gate hollow , can float. can constructed withstand high heads.
guillotine gates. locks have vertically moving steel gates – these quite common on river navigations in east anglia. 1 of pairs of swinging gates replaced guillotine: instance @ salterhebble locks, space swing balance beams of bottom gates of lowest lock restricted bridge widening. on river nene locks have arrangement in time of flood top mitre gates chained open , bottom guillotines lifted lock chamber acts overflow sluice. guillotine gates used on downstream side of larger locks such 23m bollène lock on river rhône, aperture being large enough boat travel under it.
vertically rotating gates (american usage: drop gates)

example of lock drop gate (lock 10) on chesapeake , ohio canal


are gates which, when open, lie flat on canal bed , close lifting (london flood barrier). of these installed on chesapeake , ohio canal in congested 7 locks area since operated 1 man , speed traffic.
rotating-sector gates. of these work traditional swinging gates, each gate in form of sector of cylinder. close rotating out lock wall , meeting in centre of chamber. water let in or out opening gates slightly: there no paddles or other lock gear. lock @ limehouse basin, gives access river thames, example. dramatically large 1 can seen @ maeslantkering (huge flood gates) near rotterdam. there different type @ sea lock on ribble link: rising sector gate, has horizontal axis: gate drops bed of river allow boats pass.


different paddle gear

some manually operated paddles not require detachable handle (windlass) because have handles ready-attached.
on leeds , liverpool canal there variety of different lock gear. paddles raised turning in effect large horizontal wing nut (butterfly nut) lifting screw-threaded bar attached top of paddle. others operated lifting long wooden lever, operates wooden plate seals culvert. these known locally jack cloughs . bottom gate paddles operated horizontal ratchet slides wooden plate sideways, rather more common vertical lift. many of these idiosyncratic paddles have been modernised , becoming rare.
on calder , hebble navigation, paddle gear operated repeatedly inserting calder , hebble handspike (length of 4 2 hardwood) ground-level slotted wheel , pushing down on handspike rotate wheel on horizontal axis.
on parts of montgomery canal bottom paddles used in place of side paddles. rather passing lock through culvert around side of lock gate, water flows through culvert in bottom of canal. paddle slides horizontally on culvert.


composite locks. economise, stone prohibitively expensive or difficult obtain, composite locks made, i.e. constructed using rubble or inferior stone, dressing inside walls of lock wood, not abrade boats. done, instance, on chesapeake , ohio canal locks near paw paw tunnel , chenango canal because wood swell (making lock space smaller) or rot away, wood replaced concrete.
lock keepers.

some locks operated (or @ least supervised) professional or volunteer lock keepers. particularly true on commercial waterways, or locks large or have complicated features average leisure boater may not able operate successfully. instance, although thames above teddington (england) entirely leisure waterway, locks staffed. have boaters been allowed limited access hydraulic gear operate locks when keeper not present.

powered operation. on large modern canals, large ones such ship canals, gates , paddles large hand operated, , operated hydraulic or electrical equipment. on caledonian canal lock gates operated man-powered capstans, 1 connected chains open gate , draw closed. 1968 these had been replaced hydraulic power acting through steel rams. on smaller canals, gates , paddles electrically operated, particularly if lock regularly staffed professional lock keepers. on river thames below oxford locks staffed , powered. powered locks still filled gravity, though large locks use pumps speed things up.
fish ladders. construction of locks (or weirs , dams) on rivers obstructs passage of fish. fish such lampreys, trout , salmon go upstream spawn. measures such fish ladder taken counteract this. navigation locks have potential operated fishways provide increased access range of biota.
weigh lock.


a weigh lock on lehigh canal

a weigh lock specialized canal lock designed determine weight of barges assess toll payments based upon weight , value of cargo carried. erie canal had weigh locks in rochester, syracuse, , west troy new york. lehigh canal had weigh locks (see photo on right).