"To get from the shore to the boat, there's a plywood ramp with pretty makeshift handrails. He was feeling a bit giddy and went to support himself on the handrail and it gave way."
The man tried to pull himself up and back to safety but couldn't, and his countless calls for help went unanswered.
"He'd been calling for help for ages but a mate who normally keeps an eye out for him had been away for the weekend, so no one had noticed he was missing or heard his calls. He would've been pretty distraught until someone found him."
The boatie was lucky to survive the night, said Mr Batt.
"He'd been in the elements - it'd been raining, windy, cold. He'd been in the elements overnight and he was in shock and I'd say mild hypothermia.
"He was quite lucid and very relieved to see us."
The elderly man has lived on the site for several years and was heading back to his boat after picking up a bag of Kentucky Fried Chicken, said Span Farm worker Paul Watts.
Mr Watts was told his friend was drinking rainwater overnight, and survived chilly conditions and showers of rain.
"He's only a little fella, and he's fairly plumpish. He's not fat but he had plenty of meat on him to keep him going."
Mr Watts said his mate was lucky the tides were at a lower level, because if he'd fallen last week he would have gone under.
Fire services used an emergency stretcher designed for hauling people over rough terrain to rescue the man.
Ambulance medics assessed the man at the scene before taking him to North Shore Hospital, said St John ambulance spokeswoman Viv Muir.
He is now in a stable condition and was being monitored in the emergency department, said a hospital spokesperson.
