The Spring Tower with ASD is installed outboard of the hauling winch drum and consists of a large helical spring in a spring tower, a sheave block assembly mounted on the top end, a fixed sheave block fixed to the base, and an air module and Anti-Slack Device. The spring tower absorbs shock or impact loads of varying causes, including trolley collision with either the receiving or delivery ship that might otherwise damage the hauling winch or wire rope. The ASD maintains line tension at the hauling winch during rigging operations, via a tensioning system that converts motor torque into constant wire rope tension of not less than 500 pounds at a rated line speed of 240 feet per minute.