Three men had to be rescued by lifeboat crews after their boat capsized during a drinking trip.
The men had been drinking with two other men on a moored fishing boat on the River Wear in Sunderland and tried to get back to shore on a service boat known as a tender, said Sunderland RNLI.
But the tender capsized, leaving the three men stranded in the water.
Shortly before 3.10am, Humber Coastguard requested the immediate launch of two lifeboats after receiving a 999 emergency call from the two men on the fishing boat reporting that the three men were struggling in the water near Wearmouth Bridge.
The trio managed to swim back to the fishing boat and were helped on by their companions but were suffering from the effects of the cold.
Mark Cleminson, helmsman at Sunderland RNLI said: "On arrival we were able to confirm that all of the group were safely out of the water, but three of the group were suffering from the effects of the cold.
"This incident highlights the dangers of taking part in activities on the water after consuming alcohol. The RNLI strongly recommends that people do not take part in water-based activities after drinking alcohol as drinking and seawater just don't mix and cold water shock to the system can also bring on hypothermia very quickly."
After receiving first aid on the lifeboats and further treatment from paramedics at the marina, the men were taken to Sunderland Royal Hospital suffering from the early signs of hypothermia.
Northumbria Police, North East Ambulance Service, and Sunderland Coastguard Rescue Team all helped in the rescue operation.