After nearly an hour of searching in the water, officer Matthew Rush, along with a good Samaritan, got to her.
He pulled her to safety as another officer, Sergeant Mike Dellatore, directed him from a waiting boat.
"I located the child, pulled the child down out of the hull of the boat and then up out of the water where the child was turned over to [officers] on the boat," Rush told Florida Today.
"Usually incidents like this don't turn out like that. A boating accident that severe with that much damage could have been a lot worse. Air pocket in the boat and a life jacket I would say saved her life.
"Rewarding. It is. I've only been in Cocoa for nine years. We've seen a lot of things, unfortunately, that don't go very well so when you see one like that, I'll probably never forget that image of [Kennedy's mother] holding her child at Lee Wenner (Park)."
Dellatore's wife, Dora, a trauma nurse, was also on the boat as the pair had been out for dinner when they got a call to help.
She assessed the girl in the rescue boat.
"I just made sure she was breathing. She was awake crying, coughing," she said.
"I just wrapped her up as much as I could with the life vest and my body heat just kept her awake and comforted her until we got to the shore."
Tammy Bossard told Pittsburgh's Action News: "I had Charlotte in my hands still and the boat had flipped and I climbed on top of the boat and Brian was there and pulled me up. We heard Kennedy crying and we couldn't find her.
"God was with us."
Witness Dorothy Dixon said: "Mum and dad did everything they could."
Bossard's call to emergency services was played on Pittsburgh's Action News.
"I'm in the river, a boat crashed and i have a bbay underwater," she said.
