As the Larne-based RNLI craft towed the yacht to port it was joined by a pod of dolphins, who were captured on camera.
The 30-ft yacht was sailing from Bangor to Scotland when its propeller became tangled in fishing nets.
Weather conditions were good but there was not enough wind to sail without the help of an engine.
A fisheries protection vessel was first to reach the vessel, which had two people on board, and it alerted the lifeboat crew.
Speaking following the call-out, Roy McMullan of Larne RNLI reminded anyone taking to the sea this summer to respect the water.
"Sailing and motor-boating are popular pastimes particularly at this time of year," he said.
"We would encourage sailors to always wear a lifejacket and always have a means for calling or signalling for help and ensure everyone onboard knows how to use it."
A County Antrim lifeboat crew had some unexpected sea mammal assistance when they went to the aid of a stricken yacht on Wednesday.