The final, for now, delivery in a series of four 120 by 34-ft 3200-HP Z-drive towboats was completed at Steiner Shipyard in Alabama. The innovative vessels were built for Southern Towing of Memphis Tennessee. As with the other three vessels the Arne Christiansen is powered by a pair of Tier 2 compliant Cummins QSK50 mains, each rated for 1,600 HP at 1800 RPM provides the power. The two engines are mounted aft on the main deck level. They turn short four-foot shafts to HRP Z-drives carrying 74.8-inch (1900 m/m) propellers in steerable nozzles.