"They were lucky. They had good radio comms so we knew where they were."
Maritime New Zealand has launched an investigation into the sinking.
The vessel was in the news in January, after crew were accused of dumping fish waste near a popular swimming spot in Caroline Bay, Timaru, and was investigated by the Environment Canterbury Regional Council.
Yesterday, council southern zone lead Peter Burt said its investigation found a small amount of fish waste was discharged from the vessel.
"This was not acceptable practice, even though most of the waste was quickly consumed by seabirds. We took an educational approach with the captain involved, who acknowledged his actions were not best practice and agreed to be more responsible in the future."
The skipper and owner of Aurora 7459 is Wayne "Jingles" Jolly.
Attempts to contact him have failed.
Many spoken to in the Port Chalmers fishing community described Jolly as "a colourful character" and "a loveable rogue", and said Aurora 7459 appeared to be poorly maintained.
"The last time the boat was in Port Chalmers a fortnight ago, it was looking pretty sad," said a fisherman who declined to be named.
Another fisherman, who also declined to be named, believed the boat had a current survey certificate of seaworthiness, but agreed it was not well maintained.
"I would suspect that is why it sank. There's been no maintenance on that boat. It's in a sad state."