During a three-day birthday cruise, a skipper let unqualified, inexperienced and even unwilling passengers steer a charter boat.
They were also unsupervised.
Passengers were allowed to take control of the vessel for lengthy periods, including the moment it ran aground off the north Queensland coast.
The grounding in the Whitsundays was described as "terrifying".
More than a year after the 21st birthday cruise came to an abrupt halt, the skipper has been convicted and fined more than $15,000.
The Australian Maritime Safety Authority said a litany of serious safety issues had led to the boat grounding near Hook Passage in November 2022.
The multi-day cruise began with 13 passengers enjoying birthday celebrations on private charter boat Waltzing Matilda.
However during the voyage, the skipper allowed passengers to control the vessel among a number of other safety breaches.
"The skipper also failed to provide the required standard of lifejackets for the passengers, failed to properly secure the tender to the main vessel to ensure it would not drift away and allowed multiple safety violations to occur during the grounding," AMSA said.
The skipper was charged after failing to pay fines related to the incident.
He then failed to appear at Proserpine Magistrates Court for the hearing, AMSA said.
The skipper was subsequently convicted of three offences under the Marine Safety National Law Act including reckless operation of the vessel.
"The magistrate noted in court that the grounding would have been terrifying for the passengers on board," AMSA said.
The skipper also copped the hefty fine after the successful prosecution by Commonwealth Director of Public Prosecutions on behalf of AMSA.
"If you're a domestic commercial vessel operator, there is nothing more important than safety," AMSA's David Marsh said.
"Skippers and operators should take notice that AMSA will take action if you break the law while operating a vessel."
