The Sabin Lock is the fourth lock in a four parallel lock complex. The north canal services the Sabin and Davis Locks and has a minimum maintained depth of 24.0 feet upstream and 23.5 feet downstream of the locks. The normal upper pool for the Sabin Lock is elevation 601.3 ft (IGLD 85) and the normal lower pool is elevation 580.8 ft (IGLD 85). The distance between the upper and lower entrances to the canal is nearly two miles. Since 1989, the Sabin Lock has been on inactive status and has not been used.
The Sabin Lock was built by the United States during the years 1913 through 1919 and opened to traffic on 18 September 1919. It has a length of 1350 feet between the inner gates, a width of 80 feet, and a depth of 23.5 feet of water over the sills at low water datum. The Sabin and Davis Locks are very similar in construction and design, although not all parts are interchangeable.
The Sabin Lock has three sets of gates at each end. The outer gates are used to dewater the lock chamber. The second set of gates is the operating gates and was used the most frequently to transit vessels. The inner gates are the intermediate gates and were only used when the operating gates were out of service. The operating gates have also been modified with wider walkways. Dewatering gates at each end of the lock were originally of steel bolted timber construction. The downstream dewatering gates were removed and replaced with steel gates in 1995. The upstream wooden dewatering gates are no longer used. The upper end of the lock is equipped with dewatering bulkheads, which are normally set in place by the adjacent stationary, stiff leg derrick. The stiff leg derricks have been taken out of operation or “tagged out”, so the bulkheads are currently placed by crane barge.
The filling and emptying valves of the Sabin Lock are butterfly type. The hydraulics for the butterfly valves have been updated and automated. Six filling and six emptying valves serve six under-the-floor culverts. Because the capacity of the filling and the emptying currents were greater than desired, two culverts have been removed from operation. The valves were blocked and the parts removed and secured for spares at the time of World War II. The lock has a concrete floor, which serves as the ceiling of the culverts. The walls of the lock are concrete, and do not have a service gallery. In the past, the lock walls have been resurfaced with concrete by shotcrete and prepact methods.
The Sabin Lock is one of the oldest locks in the Soo complex. In 1985, a Notice to Mariners was issued stating that the Sabin Lock was being placed on inactive status due to the deteriorated condition. There has been no vessel passage through the Sabin Locks since 1989. Therefore, the Sabin Lock’s primary function is to serve as a water retention structure for the St. Mary’s River.
In 2010, the Sabin Lock was permanently decommissioned. Cofferdams were constructed upstream and downstream of the Sabin Lock as part of the New Lock construction.