The 11m wooden boat had nobody onboard and represented a hazard in the area.
As the volunteer lifeboat crew neared the vessel they noticed a man in a punt approaching them. The man was from a nearby boat and having become concerned at the drifting vessel, had decided to investigate and see if he could assist.
However it was discovered that his nine 9m yacht, which had another crew member onboard, had also got into difficulty and was starting to drag its mooring.
Wind conditions were force four to five with a north gusting wind and lumpy seas.
The inshore lifeboat assisted the man back onboard his vessel and a lifeboat crew member joined him. The dragging mooring was fixed and they were able to continue under their own power.
The original drifting boat was aground, and having made sure the other vessel and its two crew were safe, the lifeboat returned to assist. Establishing a tow, Larne RNLI inshore crew were able to gently pull the boat off the rocks.
They were then met by the all-weather lifeboat and the tow was passed on to them before it was safely secured on a mooring in Larne Lough and both lifeboats returned to station.
Commenting on the call-outs, Larne RNLI lifeboat operations manager Alan Dorman said: “What started as a normal Sunday morning exercise turned into a double call-out for both lifeboats.
"It shows how quickly things can change out at sea and the lifeboat is always available to assist and reassure. Thankfully on this occasion help was close at hand and no injury or damage was done.”