On the afternoon of 14 December 1939, the tanker struck a mine laid by German destroyers off the Tyne Estuary. "Kelly" and the were dispatched as escorts for the rescue tugs "Great Emperor", "Joffre" and "Langton". During the operation, "Kelly" also struck a mine and sustained damage to her hull. While "Mohawk" put a party aboard "Atheltemplar", and "Joffre" and "Langton" took the tanker under tow, "Kelly" herself was taken in tow by "Great Emperor" and returned to the Tyne. Reaching the Tyne just before midnight, "Kelly" was assisted upriver by the tugs "Robert Redhead" and "Washington". She was towed to Hawthorn Leslie's yard for repairs, which took just a little over three months.