Over 100 Locks and counting…
One of the necessary parts of navigating the Great Loop is the needed passage through locks. The exact number of locks is dependent on the route taken. For example, the Erie Canal has 36 locks from the Hudson River to Lake Erie.
If loopers venture into Canada to transit the Trent Severn waterway they will first pass 1 lock on the Hudson at Troy, NY then 23 locks on the eastern Erie Canal and 7 locks on the Oswego canal before crossing Lake Ontario. The Trent Severn waterway starts in Trenton and has 44 locks, including the world’s two highest lift locks and the infamous Big Chute Marine Railway.
A lock is a device used for raising or lowering boats between stretches of water of different levels on rivers or canals. Locks were first invented over a thousand years ago in China in 9th century and the basics have changed little in changed very little in this time.
The most common type of lock on the loop are pound locks and were built in the late 19th or early 20th century. A pound lock is distinguished by a fixed chamber in which the water level is raised or lowered.
Lock Basics
A boat traveling upstream enters the lock chamber through the open downstream gate when the water level is level with the downstream level. The downstream gate is closed and the chamber is filled until the level is equal to the upstream level of the canal. The upstream gate is open and the boat exits
Erie Canal Elevation Change
The graphic above shows the elevation change along the Erie Canal between the Hudson River and Lake Erie near Buffalo to the Hudson River. The 36 locks allow an elevation change of 565 feet over 380 miles of the canal. wikipedia.org/wiki/Erie_Canal
In addition to the standard pound type locks encountered on the loop, loopers will pass through two Lift Locks; Peterborough and Kirkfield and one Inclined Plane lock The Big Chute Marine Railway. In both Lift Locks and Inclined Plane type locks the chamber rises and falls.
The Peterborough Lift Lock, lock 21 was completed in 1904 and is the highest lift lock in the world with a lift of 65 feet.
How does a Lift Lock Work?
Lift locks operate on a balance principle. A constant water pressure supports each ram through connecting pipes below ground. When extra water is let into the upper chamber, a connecting valve is opened and the heavier chamber automatically descends, forcing up the lower chamber to start a new cycle. (source: Parks Canada webpage)
The time-lapsed video below shows how the two chambers of the Peterborough lock transition, upper to lower chamber. This process takes only two minutes!
The Kirkfield Lift Lock, Lock 36 was built in 1905 and is the second highest in the world with a 49 foot lift. This time-lapsed video shows Odysea II entering the chamber on the Kirkfield Lift Lock with two other boats and lowering 49 feet before the front gate is lowered and the boats exit. The complete trip took less than two minutes!
The Big Chute Marine Railway was built in 1917 and has a lift of 58 feet. One of the prime reasons the Big Chute was built as a railway rather than a more conventional pound lock, which was the original plan, was the need to keep invasive species such as Sea Lamprey from passing from the Great Lakes to the rivers and lakes of the Trent Severn. The Big Chute is the only lock of its kind in North America but interesting enough there are a number of Inclined Plane locks in other parts of the world. More information and history on the Big Chute is available on Wikipedia.
Our Big Chute experience was seamless as we were first in line so only had to wait about 20 minutes until we were called on the loudspeaker to load into the lock.
