A man died after pulling his children to safety from the sea, then returning to save a 13-year-old girl.
Mr Mangle's wife said he was a family man who adored his children
Steven Mangle, 50, from Sheffield, was airlifted to Boston's Pilgrim Hospital after the incident in Skegness, but later died.
His 12-year-old daughter and 15-year-old son were unharmed.
He threw the 13-year-old to safety in shallow waters but then got into difficulties himself in the strong current, the coastguard said.
"With great effort, he threw (the girl) into the shallow surf so she could be picked up," said Mark Clark from HM Coastguard.
He added: "Because of the ferocity of the water, he wasn't able to be grabbed and by the time he was, he was face down."
A spokeswoman for Lincolnshire police said: "He clearly put the safety of his own children and that child before his own safety.
"He was a hero, and because of that he lost his life."
Two other men went into the water to try to help Mr Mangle after he went under the surface.
Mr Mangle's widow, Patricia, said: "He was a family man who adored his children, who enjoyed life, who never had a bad word to say about anybody."