Very large locks Lock (water navigation)

berendrecht lock (right) , zandvliet lock (left), located @ entrance port of antwerp (top) scheldt (foreground)



barges @ lock on mississippi river

the world s largest lock was, until 2016, berendrecht lock, giving access port of antwerp in belgium. in 2016 kieldrechtsluis in same port became largest. lock 500 m (1,600 ft) long, , 68 m (223 ft) wide , drops 17.8 m (58 ft), , has 4 sliding lock gates. size of locks cannot compared without considering difference in water level designed operate under. example, bollène lock on river rhône has fall of @ least 23 m (75 ft), leerstetten, eckersmühlen , hilpoltstein locks on rhine–main–danube canal have fall of 24.67 m (80.9 ft), each , oskemen lock on irtysh river in kazakhstan has drop of 42 m (138 ft). total volume of water considered in lock equals product of length, breadth , difference in water levels. lock staircases used in attempt reduce total volume of water required in relation amount of useful work done. useful work done relates weight of vessel , height lifted. when vessel lowered consumption of potential energy of water consumed considered. alternative locks boat lift; facilities of type, e.g. anderton boat lift or strépy-thieu boat lift in belgium, not rely on consumption of water primary power source, powered motors , designed consume minimum amount of water.

the 29 locks on mississippi river typically 600 feet (180 m) long while tug , barge combinations as 1,200 feet (370 m) long consisting of many 15 barges , 1 tug. in these cases, of barges locked through, using partially opened lock valves create current pull un-powered barges out of lock tied wait rest of barges , tug pass through lock. can take as hour , half pass lock.

hiram m. chittenden locks

every november, large lock of hiram m. chittenden locks (better known locally ballard locks in reference seattle neighborhood located in) emptied maintenance, seen in november 2004 pictures below. provides opportunity visualize how lock works without water obscuring bottom of lock. reference, picture far left shows lock in operation, tug , barge (loaded sand , gravel) waiting gates open. in bottom left corner of picture may seen cut-out in side wall contains gate when open.

the lock has 3 pairs of gates, 1 pair @ each end , 1 pair in middle half length of lock can used when whole length not required, saving water. barely visible person walking along bottom of lock in second picture gives indication of vast size of lock. in both pictures of end gates, string of penstock openings visible along sides @ bottom. water entering , leaving lock flows gravity through these openings. requires around 15 minutes fill or empty lock.