Whitby RNLI's all weather lifeboat was launched on Sunday afternoon after a red flare was spotted off the coast of Whitby.
The red flare, a distress signal used at sea, was spotted by a pleasure boat and reported to the coastguard.
The lifeboat was launched at 1.20pm and the volunteer crew spent four hours searching the area before being stood down.
Mechanic Richard Dowson said: "Thank you to the informant who reported the flare. This was the correct reaction as usually a flare is launched as a distress signal."
If you see anyone in danger at sea you can report it to the coastguard by calling 999.