Army tugs were seen as far back as the American Civil War with the 1862 screw tug Terror. World War II era tugs came in two general classifications, though those were not rigid and variances may particularly be seen in commercial vessels taken in early during the war. Seagoing tugs, 92'-100' or greater were designated Large Tug (LT). Harbor tugs were Small Tugs (ST). The Transportation Corps determined that at war's end it was operating 746 tugs of the LT/ST types.
