"What happened was [the dad] did a sharp turn to retrieve one of the children off the biscuit and a wave washed in. It was quickly over after that - it didn't take long to sink."
The children's mother was on shore, frantically looking on.
"Everyone was wearing lifejackets and luckily there was a big party of people on the shore that saw everything and there are lots of boats in the area. So they might have been in the water for five minutes."
They were all out of the water before the Harbourmaster jet ski arrived.
"They're all good, the dad's just a bit shaken up. Luckily there were no injuries and it's just a story to tell now. It was a smooth operation - it couldn't have gone any better really."