Editing Lock (water navigation) (section)

==Variations==
[[File:Sault Ste. Marie Lock video sequence.ogv|thumb|A series of photos of the Canadian Locks in Sault Ste. Marie to illustrate a drop of about {{convert|22|ft|m|abbr=on}} in a lock]]

=== Composite locks===
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 the locks near the [[Paw Paw Tunnel]].<ref>Kytle, Elizabeth. ''Home on the Canal''. Seven Locks Press, 1983, {{ISBN|978-0-932020-13-0}} pp. 71–72</ref> and also the [[Chenango Canal]]<ref>{{cite web|url=http://www.nps.gov/history/history/online_books/choh/composite.pdf|title=The Composite Locks|author=Bearss, Edwin C. |publisher=[[US Department of the Interior, National Park Service]]|year=1968|page=15|access-date=May 24, 2013|archivedate=July 3, 2007|archiveurl=https://web.archive.org/web/20070703035818/http://www.nps.gov/history/history/online_books/choh/composite.pdf}}</ref>

=== Powered operation===
On large modern canals, especially very large ones such as [[ship canal]]s, the gates and paddles are too large to be hand operated, and are operated by [[hydraulic]] or [[electric]]al equipment. On the [[Caledonian Canal]] the lock gates were operated by man-powered [[Capstan (nautical)|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 By 1968 these had been replaced by hydraulic power acting through steel rams.<ref>{{cite book|last1=Cameron|first1=A.D.|title=The Caledonian Canal|date=2005|publisher=Birlinn|location=Edinburgh|isbn=9781841584034|edition=4|chapter=10 Working the canal in the 1820s}}</ref>

=== Fish ladders===
The construction of locks (or weirs and dams) on rivers obstructs 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.<ref>{{cite journal|last1=Silva|first1=S.|last2=Lowry|first2=M.|last3=Macaya-Solis|first3=C.|last4=Byatt|first4=B.|last5=Lucas|first5=M.C.|title=Can navigation locks be used to help migratory fishes with poor swimming performance pass tidal barrages? A test with lampreys.|journal=Ecological Engineering|year=2017| volume=102|pages=291–302|doi=10.1016/J.ECOLENG.2017.02.027|s2cid=55266451|doi-access=free|bibcode=2017EcEng.102..291S }}</ref>

=== Sea Locks ===
Locks are installed in places where an open channel would have a strong current due to different tides on two sides of a barrier. The lock in the [[Canso Canal]] is an example.

=== Marina Locks ===
In places with significant tides, a lock can allow a marina behind it to have fixed slips, instead of the floating slips with long ramps that the tide would require. Examples include [[St Katharine Docks]], London, England; Port of Québec Marina, Quebec City, Quebec; and [[Larrakeyah#Cullen_Bay|Cullen Bay Marina]], Darwin, Australia.