"I saw the anchor rope tangled round the prop, so I lifted the motor up. With my weight at the back of the boat and the anchor grabbing, it [the boat] went over."
Mr Redman ended up in the water but managed to climb on to the upturned hull.
"I thought, 'well I'm breathing air and hanging on - I'm not going to die of drowning'."
Mr Redman said his partner Eve was at work until 11.30 that night and her mother was the only person who knew where he was.
Attempts to contact him on his cellphone failed, and police were concerned about the deteriorating weather conditions and the length of time Mr Redman had been missing.
"At the start, when I was with boat, I had an hour of incoming tide. I thought I'd let the boat go and drift in with my lifejacket and get to a sandbar," Mr Redman said. "Then I thought if I let the boat go and the tide changes, I might have the times wrong."
He decided to stay with the boat and wait for the tide to turn to free it.
"In actual fact the boat saved my life."
He said when the boat was freed up, it started floating out towards the channel.
"It was dark and I was sitting on the motor, then it hit something. I put my foot down and I was on a sandbank in knee-deep water, so I got out of the boat and was holding on there for few hours. When the tide turned, I got back on it."
When daylight came, Mr Redman headed for a farm house, tramping through mangroves.
Farmer Jack By-de-Ley was shocked to find Mr Redman, wet and trembling, on his doorstep.
Mr Redman's partner, Eve, said everyone was looking for a body, but she knew he would be alive.
"I'd just finished telling all the search and rescue people that he was like a cat with nine lives and then the phone call came that they'd found him."
- Additional reporting Amy McGillivray
