At 1508hrs a boat reported 1nm off the Thornton Bar with an engine problem and requesting assistance; 4 POB. An “All Stations” call was made and a boat responded.  Sea conditions were excellent with no swell and a 7kt wind from the NW.  The boat was located and taken under tow.  Both boats arrived back in the harbour at 1630hrs.  Thank you to the Good Samaritan.