The volunteer crew was tasked to come to the aid of a 30ft cruiser which had gotten into difficulty on the eastern shore of the lake shortly before 4pm.
The person on board reported that their vessel had suffered engine failure and was adrift.
The RNLI crew took the cruiser in tow and brought it to the public harbour in Dromineer.
Deputy Launching Authority at Lough Derg RNLI Aoife Kennedy is advising boat users to have their engines serviced before going afloat and to replace old fuel with fresh fuel.
