Alaska ferry crash blamed on speed and lack of countercurrentNov 8, 2012 12:16 PM
An Alaska state ferry went off course and struck a seafood dock on May 7 because of a navigational error by the master, who had expected currents to help him slow down, according to the state agency that owns the vessel.
The Alaska Marine Highway System said its 408-foot car ferry Matanuska went out of control at Petersburg when the captain maneuvered out of the channel in a 4.5-knot astern flood current. The port turn guided the southbound ship into Ocean Beauty Seafoods’ cold-storage pier, which was heavily damaged.
The state ferry agency has since instructed its captains to slow down when approaching Petersburg in a following current.
The port turn in Wrangell Narrows was intentional, because the captains routinely try to use a known countercurrent to help them slow the ferry before the landing at the Petersburg ferry terminal, which is southwest of the seafood facility. The vessel’s speed over ground was 12.5 knots before the accident, the Marine Highway System’s iinvestigative report said.
The captain that day was the vacation relief master, with 29 years of service. He was very familiar with the Petersburg route, the report said.
U.S. Coast Guard investigator Lt. Patrick Drayer said all of the ferry captains have used a similar strategy there in a maximum astern current.
“They use that countercurrent to take the headway down. They pull the throttles back and then slow down. It’s a common practice for that master and the normal masters and the other relief,” Drayer said. “He was expecting that countercurrent to be there for that approach, but this time it wasn’t there.”
The internal review found that the astern current continues to affect the vessel’s stern after the bow slides into the countercurrent.
“In order to slow the ship down for the docking in Petersburg with a following current, some conning officers choose to bring the ship out of the main channel and into the back eddies of the Petersburg Harbor,” the report said. “With a following current running between 4 and 5 knots, when the bow of the vessel entered into the back eddy, the stern was still being pushed ahead in the main current. The opposing current in the back eddy would have aided the bow in continuing to swing to port. The master tried to counteract the opposing forces with split engines and hard right rudder.”
In a statement to his employer, the master detailed his actions and the unsatisfactory result: “Matanuska was turned to port to allow the vessel to enter the back eddies and thus greatly reduce the speed for the dock approach. Just before the vessel entered the back eddy, the order of ‘hard right rudder’ was given along with an increase in power to the port throttle anticipating a countercurrent of the opposite effect. With no immediate observable result of the turn to starboard, the starboard engine was commenced backing in order to get the ship twisting to starboard. The ship never did turn to starboard.”
The ship’s bow crashed into the seafood facility. There was extensive damage to the concrete dock, pilings, offices, railings and a crane. As a result of the incident, the business was unable to open for the 2012 fishing season. Sixty passengers were aboard Matanuska, but no one was hurt.
The Marine Highway System cited poor judgment by the captain.
“The primary cause of this mishap is determined to be conning errors by the master who failed to adequately account for the environmental conditions and ship characteristics present and which resulted in a continuous turn to port that was not counteracted prior to alliding with the Ocean Beauty seafood dock,” the report said.
Drayer said the ferry system has instructed the masters, when they approach the Petersburg ferry terminal, to sail just fast enough to keep the ferry under control.
“They put a captain’s note out that said basically don’t rely on that countercurrent,” Drayer said. “Go back to minimum base steerage when you’re in a full flood current.”
Drayer noted that the Marine Highway System ferries are the lifeblood of many Alaska communities, and there can be public pressure to keep the sailings on schedule.
“There is not a corporate culture of going fast, but they catch a lot of flak for being late,” Drayer said. He said ferry managers are telling the captains to “slow down. We’d rather have you be five minutes late than to have something like this happen.”