The disgraced container ship captain responsible for New Zealand's worst environmental maritime disaster tried to cover up shoddy seamanship by ordering records to be changed - and then kept quiet about it to investigating authorities.

The MV Rena's captain and his navigation officer eventually admitted altering the ship's GPS log, its passage plan and its computer to mislead the investigators.

"This offending is very serious in that it caused genuine confusion for investigators trying to piece together the events that led to the grounding," said the director of Maritime New Zealand, Keith Manch.

"It is vital that when these types of events do take place, we can find out how and why they have happened to help prevent such an event happening again."


Last evening, the captain, 44-year-old Mauro Balomaga, and his navigational officer, 37-year-old Leonil Relon - both from the Philippines - were jailed for seven months.

At the sentencing hearing, it was revealed that Balomaga arranged for corners to be cut between Napier and Tauranga to fulfil what was described as an "obsession" with reaching the port by 3am.

After sailing perilously close to other coastal landmarks, including Hawkes Bay's Bull Rocks, the ship slammed into Astrolabe Reef on October 5 last year.

Yesterday, Crown Solicitor Rob Ronayne, in describing the disaster, spoke of "systemic failures", "fundamental errors" and a "gross level of incompetence" that came "close to amounting to recklessness".

Amid a catalogue of errors, Balomaga failed to familiarise himself with the position of the vessel or check whether the correct chart was being used after he arrived on the Rena's bridge at 1.52am, less than half an hour before it hit the reef.

He also did not check for dangers or hazards.

As the Astrolabe Reef came within 5.5km of the ship, it showed up as an echo on the radar.

Balomaga dismissed it as a small vessel or a radar cluster.

A crewman recorded by the ship's black box reacted as the ship hit the reef, tearing away 60m of its keel: "What was that? Put it on manual. Shit, shit, chief, chief, what happened?"

Shortly after, Balomaga discovered that the ship's position at 2am had been noted in the GPS logbook but not plotted on the chart.

The reef would have been obvious to him if this had been done.

Realising how this would look, he instructed Relon to plot a false GPS position so it looked as though the ship was sailing clear of the reef.

Balomaga also instructed Relon to create a false passage plan and to destroy the original document.

Balomaga's lawyer, Paul Mabey, QC, told the court that Balomaga realised his career was over - but he hoped that Relon's, who had a young family, could be saved.

When both men were interviewed on October 11, the day the crew were evacuated from the ship amid a heavy storm that sent 350 tonnes of heavy fuel oil into the ocean, neither mentioned the cover-up.

Only a month later did they admit what they had done - Balomaga saying he had sought to mislead the authorities to cover what he saw as Relon's shortcomings.

Mr Mabey said Balomaga had been under pressure and sleep deprived when he was first interviewed.

Relon's lawyer, Mark Beech, said there had been negligence and incompetence on his client's part, but his offending did not rate at "the top of the end of recklessness".

"He readily accepts that, given his level of experience, it should never have happened."

Judge Robert Wolff told both men their attempted cover-up was a "silly and unwise decision".

"The clear message needs to be sent that where there is national disaster such as this, it is incumbent on those involved in it to be truthful."

Balomaga says his company has stuck by him, despite having to pay $13.2 million each month for his mistake.

Speaking exclusively to the Weekend Herald on Thursday, the captain of the MV Rena said he had no idea what fate awaited him - but smiled as he told how he had been able to see his family.

In Tauranga District Court yesterday, he sat and listened attentively during proceedings and, when being sentenced, stood solemn, mute and expressionless.

Balomaga, whose five children range from school-age to in their 20s, had been a sailor for 23 years when the Rena smashed into the Astrolabe Reef last year.

His first post as captain was in 2008, and he was regarded by the Rena's owners as their most senior Filipino master.

Leonil Relon, a fully qualified second officer, had also been highly regarded.

He had not seen his wife or three children - aged 14, 8 and 6 - for 18 months and for the past nine months, had been living in a Te Puke hotel.

Their employer, Costamare Shipping, said it was continuing to meet its responsibilities as their employer.

"In particular we are providing close support to the families to assist them in the absence of their loved ones."

Mr Manch welcomed the sentences.

"This grounding has had significant consequences for the Bay of Plenty community and the country as a whole," he said.

"Today marks a milestone in the response, which is still underway."

Tauranga Mayor Stuart Crosby said the region was more focussed on restoring its international reputation.

But he still wanted a Costamare Shipping representative to visit Tauranga and apologise in person.

The company told the Weekend Herald it had extended its sincere apologies "right at the beginning".

Its subsidiary, Daina Shipping Company, also faces prosecution over the disaster, and is next in court on July 18.