Restraining line led from the towing point on a tug to a deck winch, controlling the angle of the towline.
Regulatory detail & full definition
Restraining line led from the towing point on a tug — either the towing winch or the towing hook — through a fairlead at deck level and onto a deck winch. The gob rope controls the angle of the towline relative to the tug's centreline, preventing the line from sweeping across the tug's quarter and reducing the risk of girting. The operator can pay out or heave on the gob rope to alter the tug's working position relative to the tow without changing the tow or main winch line.