The in-danger vessel was heading north under sail and had reached Dunnottar Castle, just south of Stonehaven, when the wind dropped at around 1am on Thursday, May 27.
Attempts by the two people on board were made to start the engine of the boat, but these were not successful.
Weather conditions at the time were very good with flat calm seas.
However, there were growing concerns that the tide might pull the boat towards the rocky coast.
The UK Coastguard called out the Stonehaven RNLI’s inshore lifeboat Jamie Hunter, which was launched at 4am.
RNLI reached the vessel and confirmed the two members of crew were safe and well.
Paul Sim, RNLI crew mechanic was taken on board and having assessed the situation, was able to get limited power from the engine.
This allowed the sailing vessel to be escorted into Stonehaven harbour just after 7am.
Speaking just after the call-out, helm Andy Martin said: "It was certainly an early morning pager call for our volunteer crew, and they quickly got to the scene.
"It had the potential to become quite dangerous for the sailing vessel, but Paul’s mechanical experience and expertise came in very handy.
"We are pleased to have been able to help and the situation worked out with everyone recovered safe and well.”