Ritchie O'Neill only wanted to help, but that instinct and effort nearly cost him his life.

"I was really scared," he admits.

O'Neill was at Petrie Island Tuesday afternoon with his son when he ventured out beyond the buoys to try to retrieve a beach ball that had gotten away from a young girl.

"The thing was running away from me," he says. "Every time I went to it, it kept going further and further and further."

O'Neill can swim, but he uses his prosthetic leg to do it. When he got out to deeper water, the leg fell off.

"I was panicking...it sinks fast so I dove down to grab it. I got it, but now I'm holding on to the leg, floundering with one arm and one leg," a scared O'Neill recounts.

He couldn't stay above the water, so he had to choose between his life and his leg. He let the leg fall, but still struggled to swim through the current. O'Neill thought he was going to drown, when a woman grabbed his hand and pulled him to shore.

His frightened son watched the whole ordeal from the beach.

"I thought he was going to die," his son says. "It was very, very scary and I wouldn't know what to do without my dad."

O'Neill called his wife to come get him and his son. When he got home, he shared his experience online about the strong current and a push to have a lifeguard start earlier than 12:00 p.m. at the beach.

Friends and others who saw the post offered to help find the prosthesis. A new one would cost between $10,000 and $15,000. They were planning to bring scuba diving gear to search the water for it.

For now, he's using an older and smaller prosthetic leg and admits the experience has been embarrassing, but he's alive.

"Very grateful."