Located in Sault Ste. Marie, the Soo Locks are an
integral part of water transport in the Great Lakes. The locks were
first activated in 1855 and have seen constant use since then. The
Locks can accomodate ships up to 105 feet wide and more than 1000 feet
in length.
Boats enter the Soo Locks, where a change in water
level occurs, either raising or lowering the boat by the 21 foot difference
in water level in Lake Huron. Massive valves allow the water to flow
from the lock chamber into the next section.
Northernway's Soo Locks Page: project..northernway.net/local/soolocks.html
USACE's Soo Locks Entrance:
http://sparky.nce.usace.army.mil/SOO/soohmpg.html