OPA-LOCKA -- Saving lives is part of Petty Officer Jonathan Rivera's job description. AU.S. Coast Guardflight mechanic, he has operated hydraulic lifts in aircraft to raise victims from the sea during scores of rescues, including from cruise ships.

But it was for giving off-duty aid to a drowning man on Memorial Day 2011 that earned Rivera the rarely awarded Silver Lifesaving Medal.

Ninety Coast Guard personnel from Air Station Miami in Opa-locka watched Tuesday when Rivera, 32, was called decisive and selfless for saving the life of singer Sean Kingston.

During the holiday, Rivera, his wife Carmen, 34, a teacher, and another couple were cruising Biscayne Bay in his 23-foot Bayliner Capri near Miami Beach when they heard screams.

"Many people watch, but very few take action," said Capt. Richard Kenin, 7th Coast Guard District chief of staff.

The man who grew up near Homestead and enlisted in 2005 nosed his boat toward a hysterical scene: Two people were on a personal watercraft, pointing and screaming. Two others, a woman in a life jacket and a man, face down and sinking in the water, had fallen from their watercraft after it accidentally crashed at high speed into the Palm Island bridge. There, other bystanders were looking down, officials said.

Carmen Rivera called 911.

Though he weighs just 165-pounds, Rivera brought the bigger man to the surface and took him to a personal watercraft. He held the head of the singer, who was vomiting and nearly unconscious, above the water for 10 minutes until Miami Beach Police and EMTs arrived, officials said. Rivera aided the second victim as well.

Kingston, famous for his hit "Beautiful Girls," stays in touch through texting and Twitter, his rescuer said.

"I didn't know who he was at the time," Rivera said. "It was just a reaction. Someone was drowning."

After the ceremony attended by his wife, their son Jonathan, 5, his mother Tahidy Souto, brother Joel Souto, 14, and friend Oliver Prat, the Coast Guard gave Rivera the rest of the day off.