Delivering the findings today, TAIC Commissioner John Marshall QC said the grounding was not attributable to any equipment malfunction, but rather poor planning and execution.
The passage plan did not meet standards of best practice, and a shortcut that was taken to reach the Port of Tauranga by 3am - which instead led straight to the reef but only would have saved a minute had it not been there - increased the risk and "contributed directly".
There were also failures in the standard of watch-keeping in almost all aspects, the navigating crew were not strictly following company procedures, and monitoring equipment also wasn't used adequately.
By the time Mr Balomaga took control of the ship, shortly before the impact, he had received virtually no information about the course.
Mr Marshall said fatigue was likely, at least, to have affected performance but there was insufficient evidence to determine if actions attributable to it.
The investigation further found that the navigating crew had not been following the safety management system for at least the six coastal voyages prior to the grounding; that deficiencies had been spotted on the Rena at previous ports overseas; and that international protocols for auditing training standards "lacked transparency".
An independent audit had found Philippines' maritime education, training and certification system did not meet mandatory standards enforced by the International Maritime Organization (IMO).
The commission recommended that the company which managed the Rena, CIEL Shipmanagement S.A, "evaluate the effectiveness" of its safety management system, and that Maritime New Zealand (MNZ) push, through the IMO, for greater transparency of the system for auditing countries' seafarer training systems.
"They had become routine'
The investigators found that the acts and omissions weren't one-offs, Mr Marshall said.
"They had become routine, that was the way they were operating and that is an indication of the safety system of which they were operating under, which goes back to the management of the shipping company as well."
Of 12 vessels managed by CIEL, the average rate of deficiencies found per inspection under the Tokyo Memorandum of Understanding was 3.4, but the Rena's rate was 6.3.
Only two others - the Konstantina (10) and the Garden (11) had higher rates of deficiencies.
"Looking at the wider system, there were issues found with the Philippines training system," he said.
"However, what we can say is that the International Maritime Organization is trying to address this problem at a global level, because it is a global thing."
The commission further recommended that MNZ collect sufficient data on shipping movements around the New Zealand coast, and "monitor and control" the use of virtual aids to navigation around the coast.
A lack of data meant it wasn't possible to make any meaningful analysis to see whether there was any need for ship routing in some form around the coast.
However, MNZ director Keith Manch told the Herald ship routing normally occurred in areas where there was a huge amount of traffic, "and there isn't a huge amount of traffic in New Zealand".
"It's not that there isn't enough traffic for ship routing, it's just that the conditions haven't been seen to exist previously for it."
MNZ would consider the option in a new review which would give a comprehensive analysis of factors contributing to risks around shipping.
It would also consider the virtual aids suggested by TAIC.
Mr Marshall said if a light on the reef "probably would have helped" avoid the grounding, but there were a number of such hazards around the country and the costs and advances in technology had to be considered.
A simple chart plotter or plotter integrated with radar came with low cost, and would have visually alerted the bridge to the reef.
Virtual aids were an alternative, Mr Marshall said, but should not be introduced before proper research and a development of standards.
Asked whether the investigation would stop a repeat of the Rena disaster happening, Mr Marshall said it would go "some way".
"It is going to take time - it's not going to be fixed overnight, and that's why we say in the report that it's a lesson for ship owners."
Mr Manch said he believed the grounding had had an impact on safety measures in the wider industry.
"People, generally speaking, would have reacted quite carefully to seeing what had happened - this report adds to that."
But he felt it was still time that a thorough review be taken of risk issues around the coast.
"You've just got to look at the developments in shipping, the size of ships, and the technology involved in keeping them safe - that's changing dramatically.
"It's really time to think, are the current regulatory safety settings appropriate, or should they be updated?"
Read the full report online here:
Recommendations dealt with: owners
Responding to the report, the Rena's owners, Daina Shipping Company, noted the findings had highlighted that CIEL had already dealt with the recommendations.
"The owners and managers had an extensive engagement with TAIC during its three year inquiry for which they are grateful," the owners said in a statement.
"It has been a productive exercise and they have already been invited to and did provide input to the commission on areas where they do not agree with the commission's approach."
Transport Minister Simon Bridges could not be contacted for comment.
Labour's transport spokesperson, Megan Woods, said the findings showed some serious issues associated with the grounding.
"The report makes it clear that to adequately protect our environment we need to have strong safety management systems in place," she said.
"The Rena disaster revealed that we currently do not have adequate systems in place; we need to do more.
"The Government needs to do all it can to ensure that disasters like this do not occur again and it needs to accept the recommendations of the report."
Ms Woods added that it took "too long" for authorities to respond to the oil spill, "and New Zealand does not have sufficient response capability if there was to be a larger spill".
Green MP Gareth Hughes claimed the findings supported the Greens' call for shipping lanes, and if there had been some form of mandatory form of ship routing, the Rena would more than likely have avoided grounding.
"The Rena captain himself has recommended the use of compulsory shipping lanes, and now the Government's inquiry now the Government's inquiry has signalled there is merit in the idea," he said.
"We need to stop delaying action and start taking the steps to prevent another major oil spill on our beaches."
Shipping expert John Riding, a senior partner at marine and risk consultants Marico Marine, said the report backed his continuous calls for a GPS-routing system for New Zealand.
"There is still in no doubt in my mind that traffic routing in my mind is needed on the East Coast of New Zealand, and that includes approaches to Tauranga and Auckland."
He had previously tracked a passenger vessel - a cruise liner 280m long and capable of carrying 2500 people - going straight through the Mercury Islands.
Collision course
The Rena had left the New Zealand port of Napier at 10.20pm on October 4, 2011, bound for the Port of Tauranga.
The master, Mauro Balomaga, had given an estimated time of arrival at the Tauranga pilot station of 3am the next day.
According to the TAIC report, Balomaga calculated the estimated time of arrival by dividing the distance to go by the Rena's normal service speed.
The calculation did not account for the unfavourable currents that normally prevailed down that stretch of coastline.
After departure from Napier, he learned from notes on the chart of the unfavourable currents, and then authorised the watchkeepers to deviate from the planned course lines on the chart to shorten the distance, and to search for the least unfavourable currents.
The Rena's second mate, Leonil Relon, took over the watch shortly after midnight on October 4.
He calculated that the Rena would arrive at the port of Tauranga pilot station at 3am at the ship's then current speed.
Times for ships entering and leaving Tauranga Harbour are limited by the depth of water and the strength of the tidal currents in the entrance channel. Tauranga Harbour Control informed the second mate that the latest time the Rena could take the harbour pilot on board was 3am.
The planned course to the Tauranga pilot station was to pass two nautical miles north of Astrolabe Reef before making the final adjustment in course to the pilot station.
The second mate decided to reduce the two miles to one mile in order to save time.
The second mate then made a series of small course adjustments towards Astrolabe Reef to make the shortcut.
In doing so, he altered the course 5 degrees past the required track and did not make an allowance for any compass error or sideways "drift", and as a consequence the Rena was making a ground track directly for Astrolabe Reef.
Meanwhile, Balomaga had been woken and arrived on the bridge to prepare for arrival at the port.
He and Relon discussed preparations for arrival at the pilot station.
Balomaga then assumed control of the ship, having received virtually no information on where the ship was, where it was heading, and what immediate dangers to navigation he needed to consider.
During this period of handover no-one was monitoring the position of the ship.
At 2.14am, the Rena ran aground at full speed on the reef.
The road ahead
An application by the owners to leave much of the wreck of the Rena will be heard by a panel of independent commissioners appointed by the Bay of Plenty Regional Council in the first half of next year.
It had been earlier expected that the application for resource consent to leave what remains of the ship would be referred directly to court but, in an announcement earlier this month, the owners and insurers have opted to take a different path.
Part of the wreck, including its cargo and much of the surrounding debris, has been removed from the reef off the coast of Tauranga, in a costly salvage operation which began when the ship struck the reef.
The owners' decision followed a review of the regional council's technical report, which outlines a number of conditions for consideration should consent be granted.
