Crews from Broughty ferry Lifeboat Station were called out to help a man from the River Tay.
The man was found in the water near the oil rigs in the early hours of Friday morning.
He was recovered by the team’s in-shore lifeboat (ILB) before being brought to the larger ship for a health assessment.
The crew then took the man back to land, where he was taken to Ninewells in an ambulance.
Coxswain Murray Brown said: “We were called out just after 3am and we recovered the man by about 3.20am.
“He was down beside the oil rigs, we took out both boats and he was picked up by the ILB and brought back so we could check if he was okay.
“Police and the ambulance were both there too, he was taken away in the ambulance after.
“We were back by at least 4am, so it was a quick one, a good job from us.”
Police Scotland spokesperson said : “Officers received a report of concern for a person in the River Tay at 2.50am.
“He was recovered by the Coastguard and taken to hospital for treatment.”