The Davis Lock is one of the two older members of a four-lock complex located on the St. Marys River. The north canal serving the Davis and Sabin Locks has a minimum depth of 24.0 feet upstream and 23.5 feet downstream of the locks. The normal upper pool for the Davis Lock is elevation 601.3 ft (IGLD 85) and the normal lower pool is elevation 580.8 ft (IGLD 85). The length between the upper and lower entrances is nearly two miles.
The Davis Lock was built by the United States during the years 1908 through 1914 and opened to traffic 21 October 1914. It is 1350 feet long between the inner gates, 80 feet wide, and has 23.5 feet of water over the miter sills at low water datum. The Sabin and Davis locks are very similar in construction and design. Although not all parts are interchangeable, some parts have been exchanged between both locks. The filling and emptying valves 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 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 outer gates have been modified with wider walkways. The locks are equipped with two upper and lower operating gates. The inner gates are used primarily when the outer gates are out of service. 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 1988. 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 derrick has been taken out of operation or “tagged out”, so the bulkheads are currently placed by crane barge.
The lock walls of the Davis Lock have been refaced with concrete by using shotcrete methods. The lock floor has also been resurfaced. The lock floor and culverts are constructed of concrete. The lock filling and emptying culverts are located below the floor. The lock walls are concrete and do not have a service gallery. Currently, the Davis lock is only used for Soo Area Office vessels when necessary.