The investigation also revealed deficiencies in Transport Canada's oversight of passenger safety regulations — a problem flagged during two previous marine investigations and a TSB "watchlist issue."
"The TSB is calling on Transport Canada to implement regulations requiring all operators in the air and marine industries to have formal safety management processes, and for effective oversight of these procedures," the independent agency said in a statement on Thursday.
"When companies are unable to effectively manage safety, the regulator must not only intervene, but do so in a manner that succeeds in changing unsafe operating practices," it states.
The Princess of Acadia ferry from Saint John, N.B., was preparing to dock in Digby on Nov. 7, 2013, but as the bow thruster was started, the main generator blacked out, causing a loss of electrical power and disabling the main propeller pitch control pumps.
With the engines still running, the propeller then started to turn in reverse at full speed, causing the vessel to stop and drift backwards onto the nearby shoreline with 87 passengers and crew members on board, according to the TSB report, released on Thursday.
No one was injured and no pollution was reported, the report states. The ferry was able to dock after the tide came in.
Bridge, engine room failed to communicate
Investigators concluded a deteriorated generator component caused the failure of two main generators and the blackout of the main electrical switchboards, among other system failures on the ferry, which is scheduled to be taken out of service later this year.
Meanwhile, the bridge and engine room both had ineffective procedures in place to respond to the blackout. As a result, the master wasn't told the engine room staff were having difficulty restoring power, and the engine room didn't realize the urgency of the situation, which impeded an effective response, according to the report.
Bay Ferries Limited, the ferry's operator, said in a statement on Thursday that prior to the incident, inspection of the electrical components and maintenance of the equipment in question had been conducted "at all times as required by the vessel's classification."
Regular communication also took place between the bridge and the engine room, it said.
Having said that, Bay Ferries has already acted on some of the TSB's recommendations, according to Don Cormier, vice-president of operations and safety management.
Among the changes:- Improved thruster testing on arrival at Digby.
- Better staff deployment in the engine room when arriving in Digby.
- A back-up battery power supply to the vessel's navigational equipment.
- Installing a simplified voyage data recorder, which records 12 hours of bridge audio and data from the radars, automatic identification system, and other available sensors.
"Since this incident took place more than a year ago, we looked at what we can do better as an organization and proactively took action," said Cormier. "This report will help our company continue to act to ensure safety is at the centre of everything we do at Bay Ferries," he said.
Age of vessel 'irrelevant'
Asked whether Bay Ferries has gone far enough with the changes, Pierre Murray, TSB's regional manager for Atlantic Canada, said: "Only time will tell."
The age of the Princess of Acadia is "quite irrelevant in this case," said Murray.
"The components on any vessel are maintained, upgraded and replaced all through the ship's life," he said.
The Princess of Acadia is being replaced by a vessel the federal government purchased from a Greek operator last fall.
That ferry, formerly known as the Blue Star Ithaki and now being called Canada 2014, is being overhauled and modified in Halifax.
It will be renamed with input from the public before taking over the Saint John to Digby service, likely this summer, Cormier said.
The Princess of Acadia started sailing across the Bay of Fundy in 1971.
The two other marine investigations that found problems with Transport Canada's oversight to ensure compliance with passenger safety emergency procedures involved the grounding of the passenger and vehicle ferry Jiimaan in Kingsville, Ont., on Oct. 11, 2012, and the grounding of the passenger vessel Louis Jolliet off Sainte-Pétronille, Îlesd'Orléans, Que., on May 16, 2013.
The TSB investigates marine, pipeline, railway and aviation transportation occurrences. Its sole aim is the advancement of transportation safety, not to assign fault or determine civil or criminal liability.