A lawyer for the captain of the USS Greenevillelast night attacked the findings of a US Navy investigator.
It was a preview of the defence that the sub commander was not to blame for the ramming of a Japanese trawler in which nine people died.
Mr Charles Gittins, the civilian attorney representing Cmdr Scott Waddle at a court of inquiry, took issue with testimony by Rear Adm Charles Griffiths that Cmdr Waddle and his crew made a series of mistakes - some of them prompted by the presence of civilian guests on board - that caused the February 9th collision.
An attorney for a second Greenevilleofficer who faces possible discipline in the inquiry, Lt Cmdr Gerald Pfeifer, also challenged Mr Griffiths's assertions - particularly the notion that Lt Cmdr Pfeifer knew Cmdr Waddle was hurrying the submarine through manoeuvres but did nothing to intervene.
The court of inquiry, which is being conducted at the Pearl Harbour naval base and loosely resembles a civilian trial, was convened to determine what discipline - if any - Cmdr Waddle, Lt Cmdr Pfeifer and junior grade Lt Michael Coen should face.
None of the three men have yet addressed the inquiry. Cmdr Waddle - who has already lost his command of the Greeneville- and Lt Coen have asked for immunity against criminal prosecution if they testify.
Navy officials are still considering those requests.