One of the reasons you didn't see more posts from me back in September was I was trapped. The vessel I was commanding was caught upstream of The Dalles Lock on the Columbia River when the lock had a mechanical problem. The lock was shut down for a week and a half, leaving me, my passengers (and those on a few other passenger vessels), and many tugs and barges with wheat, fuel, and garbage trapped on the wrong side of the dam. Navigation locks of many sizes are key components in the infrastructure that smoooths international trade.
Leonardo Da Vinci is given credit for imagining the first modern navigational lock, although the concept dates to ancient times. Simply put, a lock is a chamber that can be filled or emptied with water to allow vessels in it to sail between water lying at different altitudes. They are often built to help vessels get around or through some obstruction, whether its a hydroelectic dam (like The Dalles) or the Isthmus of Panama (like the Panama canal locks).
Some locks have rises or falls of only a few feet; many in Europe are operated by hand by boat skippers as needed. The locks at China's Three Gorges Dam will, when completed, move vessels up or down 350 feet. The John Day lock, not far from The Dalles lock, is the largest in the United States, with a vertical lift of 110 feet. It and The Dalles are part of the eight-lock Columbia and Snake River system, which allows vessels to transit from the mouth of the Columbia at sea level, to Lewiston, Idaho, 465 river miles from the sea and 745 feet above sea level.
Other famous locks and canals:
Erie Canal. The 524-mile canal, now called the New York State Canal System, connects Lake Erie with the Hudson River. Originally opened in 1824, this canal and its 34 locks now serve mainly recreational traffic.
Kiel Canal. The 61-mile long canal, opened in 1895, connects the Baltic Sea to the North Sea, allowing vessels to cut through the Jutland Peninsula. There are locks at each end. The Kiel Canal claims to be the busiest artificial waterway in Europe.
Oldest operating locks. Six locks on the Great Britain's river Avon between Bath and Bristol may be the oldest operating navigational locks, dating to 1728.
Panama Canal. The 48-mile long canal has three sets of locks and connects the Caribbean Sea to the Pacific Ocean. When it was completed in 1914, it cut travel time from New York to San Francisco by more than half. The Canal's Gatun Locks are pictured above.
Suez Canal. The 119-mile waterway between the Red and Mediterranean Seas is entirely at sea level and contains no locks. It opened in 1869. Transiting the Suez Canal used to save shipowners significant time and money over a trip around Africa, but faster ships and recent piracy in the area have led some shipping companies to re-route some ships all the way around Africa.
Upper Mississippi. Twenty-six locks regulate the channel of the Mississippi from Minnesota's Lake Itasca to the mouth of the Ohio River near Cairo, Illinois. The Ohio itself has twenty-one locks below Pittsburgh.
Welland Canal. Seven locks over 27 miles allow vessels to bypass Niagara Falls between Lake Erie and Lake Huron.
The US Army Corps of Engineers has an informative short animated demonstration of how the Soo Locks between Lakes Superior and Huron work here.
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