A rescue mission was launched after a distress alert was set off in the River Medway.
Medway Coastguards, the Sheerness RNLI lifeboat and the RAF Helicopter Sea King began searching for the vessel just before 2pm on Friday.
It began after Thames Coastguard received information that an Emergency Position Indicating Radio Beacon (EPIRB) had been activated in the river.
Witnesses said the helicopter was still hovering over the Rochester and Strood area at 5pm.
A spokesman for the coastguards said: “The rescue helicopter was able to resolve the location to the vicinity of Strood Yacht Club. It was determined that there was no vessel in distress and it was believed to have been a spurious activation. Investigations are ongoing.”