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Soo Locks History

   The St. Marys River is the only water connection between Lake Superior and the other Great Lakes. Near the upper end of the river the water drops 21 feet over hard sandstone in a short ¾ mile long stretch. This rapids, or “sault” to use the original old French term, made it impossible for trade vessels to pass. Vessels had to be unloaded and their contents portaged around. In 1797 the first lock on the St. Marys River was constructed on the north shore to provide passage for trade canoes.
   This lock was destroyed by American forces during the War of 1812 and cargoes once again had to be unloaded, hauled overland, and reloaded until a new lock opened in 1855.

State Lock 1855 - 1888

   Built by the State of Michigan on the south shore of the river, this project was financed by a congressional land grant of 750,000 acres of public land to the company that successfully built the lock to the required specifications and within the two year deadline. The E&T Fairbanks Company, a Vermont company investing in mineral resources in the state won the contract and with Charles T. Harvey on site to oversee operations completed two locks, each chamber measuring 350’ long, 70’ wide and 12 feet deep with a lift of 9 feet in less than two years.
   The State of Michigan operated and maintained the locks but as shipping traffic grew and vessel sizes increased it became apparent that a second, larger lock was needed. Lacking the resources to undertake the construction of a new lock, the State sought support from the Federal Government.

Weitzel Lock 1881

   By the 1870s it was clear that the operation of the lock at the Soo was of national significance and the State of Michigan passed legislation to turn it over to the federal government. Although it would be several years before the federal government formally accepted ownership and management of the facility, congress began appropriating funds to build a new, larger lock. This lock, eventually named the Weitzel Lock was 515 feet long, 80 feet wide and 17 feet deep and had a lift of 20 feet. Unlike the State Lock which filled and emptied through sluices in the gates, the Weitzel Lock filled and emptied through openings in its floor, reducing the turbulence in the lock. Every lock built at the Soo since then has used this innovation. Upon completion the Weitzel Lock was formally turned over to the federal government and the U.S. Army Corps of Engineers has operated and maintained the locks ever since.

(First) Poe Lock 1896

   Within six years of opening the Weitzel Lock, work began to build an even larger lock to replace the outdated State Lock. Traffic and boat sizes continued to increase and long waits for the Weitzel Lock were common. The new lock would be 800 feet long, 100 feet wide and 21 feet deep. The Poe Lock would also be the first lock on the St. Marys River to use lock gates made of steel rather than wood.

Davis Lock 1914

   In the early years of the 20th Century boat sizes began to push the limits of the Poe Lock’s capacity. Originally designed to lock up to four vessels at a time, by 1905 boats were up to 569 feet long and had to be locked through one at a time. To cut down on delays and to handle more than one boat at a time, a plan was developed to build a new lock 1,350 feet long, 80 feet wide and 24 feet deep. Boats passed the 600 foot mark when the 613 foot long Col. James M. Schoonmaker was launched in 1911.

Sabin Lock 1919

   Recognizing the need for another lock to accommodate the growing number and length of boats in Great Lakes fleet, a fourth lock was approved and work began in 1913, a year before the completion on the Davis Lock. The Sabin and Davis locks were built to the exact same specifications using the same plans. Unlike previous locks, the Davis and Sabin were the first on site with concrete walls rather than stone masonry and used electric winding machines to open and close the gates.

MacArthur Lock 1943

   With three larger, newer locks in operation, the Weitzel Lock with its relatively shallow draft saw little use after 1919. By 1936 channels in the St. Marys River had been deepened to 24 feet and shipping companies began calling for a new, deeper lock as vessels had the capability of operating with deeper and deeper drafts. The project received a boost when the U.S. was drawn into World War Two and maintaining a steady supply of iron ore to steel mills became a matter of national security. Construction of a new lock to replace the Weitzel was approved in March 1942 and construction was completed in less than two years.

(Second) Poe Lock 1968

   Vessel sizes continued to increase and began to push the limits of even the MacArthur Lock by the 1950s. To meet the growing demand for larger and larger vessels, planning began in 1958 for a larger and deeper lock to replace the 60+ year old Poe Lock. The completed plans called for a lock 1000 feet long and 100 feet wide and construction began in 1961. Fairly quickly into the project it was clear that an even larger lock was needed and the lock was redesigned at its current 1200 X 110 foot dimensions. The lock began operating in October 1968 and in less than four years would lock through the first 1000-foot long vessel on the Great Lakes.