Fraserburgh Lifeboat was called out on Tuesday evening after a fishing vessel broke down off the coast.
The Willie & May Gall was launched at 8.10pm to the aid of the Starlight Rays, which was being towed into Fraserburgh Harbour by Kjelsvik.
The harbour pilot boat had gone out to take over the towing operation. Once on the scene the Kjelsvik had tried to get the tow rope off but only managed to get it stuck round its propeller, immobilising both vessels.
The pilot boat took the Starlight Rays into the harbour, while the lifeboat took Kjelsvik safely into port.