THURSO lifeboat was called out on Monday night after Aberdeen coastguard received a 999 call from a member of the public who reported a red flare in the vicinity of Dunnet Bay.
The RNLI lifeboat, The Taylors, launched in good sea conditions and good visibility just before 8pm and proceeded to Murkle Bay to begin the search.
The crew continued searching round to Castletown harbour followed by the Dunnet and Dwarwick areas of the bay.
While carrying out the search, a nearby fishing vessel spotted something further offshore to which the lifeboat responded but found it to be rubbish and not debris.
After enquiries had been made by local coastguard teams and a thorough search of the area had been carried out, the lifeboat was stood down.
It returned to Scrabster at 9.15pm ready for its next service.