About Revisions Lock 21 Conrwall, Ontario, Canada Max Depth: 61-70ft/19-21m Average Viz: 11-15ft/3-5m Entry Type: Shore Bottom Composition: Sandy Clay Aquatic Life: Might See Something Spring: 50-55°F/10-13°C Summer: 66-70°F/19-21°C Fall: 56-60°F/13-16°C Winter: Under 50°F/10°C 8/25/2008 5:00 PM

Lock 21 was built in 1885-86 as part of the second enlargement of the old St. Lawrence River canal system. More information: http://www.saveontarioshipwrecks.on.ca/Diverguides/dguide2.html Brought to you by Ontario Underwater Council: http://www.underwatercouncil.com/