Complex sentence: "Zur Schleuse" means a lock in the nautical sense, and the inn is thus named because it is located close to the lock by which the barges left the Semkenfahrt and came into the river Wümme.
Split into simpler sentences: Zur Schleuse means a lock in the nautical sense. And the inn got it's name because it is located close to the lock by which the barges left the Semkenfahrt and came into the river Wümme.