A sea and air search was launched after an empty dinghy washed up on on a beach.
RNLI crews said they had received reports a person had been seen on board an dinghy off the coast at Telscombe Cliffs, near Brighton, shortly after 1pm today.
The unmanned eight foot grey boat was discovered minutes later on the shoreline by the Portobello waterworks, near to the Badger's Watch pub in Telscombe Cliffs.
The Met Office described sea conditions yesterday as rough. Winds were gusting at speeds of 40mph.
Lifeboats were launched from both Brighton and Newhaven to mount a search of the water, joined by Solent Coastguard's helicopter.
RNLI Brighton spokesman Mark Bell said the search was eventually called off at 2.30pm after the whole area had been comprehensively checked.
Crews coordinated by the coastguard searched up to two miles out to sea and as far along the coast as Newhaven.
Mr Bell said: "As the search progressed it was considered the vessel may not have been occupied as initially was believed to be the case."
He said it was possible the dinghy may have been a tender which had come loose when being towed by a yacht.
Solent Coastguard has appealed for anyone with information about the unnamed Wetline 235 rigid inflatable boat to contact them on 023 9255 2100.
A spokesman said: "Vessel owners should ensure that tenders or dinghies are clearly named or identifiable in some way. If one is lost it should be reported to the coastguard immediately to ensure incidents such as these can be concluded swiftly."
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article