A fatal boat crash beneath Sydney Harbour Bridge was a "failure of seamanship" resulting from both human error and systemic failures, a coroner has found.
A group of professional ice skaters, judges and their families - aged between six and 80 - were on a late night cruise when their boat, the Merinda, and a ferry, Pam Burridge, collided under the bridge on March 28, 2007.
Skating star Morgan Innes, 14, elite skating judge Simone Moore, NSW Ice Skating Association president Alan Blinn, and Mr Blinn's friend James Engert were killed in the crash.
The inquest into their deaths was told that the Merinda did not have any navigation lights on at the time of the crash.
The Pam Burridge was also travelling at a speed that left no margin for error or for anything unexpected, the inquest heard.
The inquest was also told the skippers of both vessels also did not maintain a proper lookout.
Deputy State Coroner Hugh Dillon on Tuesday accepted those elements of the evidence, adding there was not a regular practice from commercial operators to report unlit vessels on the harbour and there were inappropriate licensing regulations.
"The accident of March was, in essence, a failure of seamanship," Mr Dillon said on Tuesday.
But, he said, the inquest was not about finding scapegoats and he praised the actions of those involved in the rescue of victims.
Mr Dillon also made 25 recommendations to improve safety on the harbour.