Autopilot sends cruise ship passengers flying

The U.S. Coast Guard is evaluating the need for guidelines governing the use of autopilots following an incident aboard the cruise ship Norwegian Sky that sent passengers and objects flying.

The 848-foot vessel was returning to Puget Sound from an Alaskan cruise on May 19 when it veered sharply to port as it approached the Strait of Juan de Fuca. The suddenness of the turn made the ship roll sharply. The forces generated by the turn were so great that swimmers were washed out of a pool as torrents of water sloshed out, according to a passenger interviewed by The Seattle Times.

The unanticipated turn “put things in motion, including people,” said Lt. j.g. Scott Casad, investigating officer with the Coast Guard Marine Safety Office for Puget Sound.

The autopilot is believed to have been responsible for the hard turn. The ship was on its intended course between waypoints, when the autopilot received a signal that caused the abrupt change in direction. “The autopilot started the sequence of events that led to the hard turn,” Casad said. “It received a heading contrary to the intended track line. That’s what initiated the rudder.”

The Coast Guard has been trying to determine the source of that incorrect heading command. The problem could have originated in the computer hardware or software, or it could have been the result of human error. But so far, investigators do not have an answer. “We haven’t been able to find that smoking gun,” Casad said.

Of the 2,975 passengers and crew on board, 78 were injured. Thirteen of them required treatment and two people were admitted to a hospital in Victoria, British Columbia. The injuries ranged from bumps and bruises to broken bones, according to Casad.

During the turn, the rudder moved 20°, inducing a roll estimated at 8° by the first officer on watch. At the time, the ship was making about 22 knots.

Norwegian Sky was still in open water when it went into its turn. The nearest land, Cape Flattery, at the northern tip of the Olympic Peninsula, was about seven to eight miles away. The ship was about 60 miles from the point where it would normally pick up a pilot.

The mishap has heightened concern about how automatic navigational devices are used. Norwegian Cruise Line said it would suspend use of the autopilot while it conducts its own investigation.

No standards for the use of automatic navigation systems exist for most ships, a situation that Capt. Michael Moore, captain of the Port of Puget Sound, may want to change. “His concern is that we don’t have a real good understanding of how autopilots are being used, what the industry standards are,” Casad said. “The only ones we are aware of are for tankers.”

Casad said he does not know what recommendations the Coast Guard will make in its report on Norwegian Sky, but he is sure they will address the use of autopilots.

The report will go to Coast Guard headquarters in Washington, D.C. If the Coast Guard concludes that new rules governing autopilots are warranted, federal legislation might be required to give the Coast Guard the authority it would need to issue the regulations.

The president of Puget Sound Pilots recognizes the need to examine the issue. “We support the Coast Guard looking at these systems as used in confined waters or pilotage waters,” said Capt. Bill Bock. “To my knowledge there are no rules about when these systems can be used or not used.”

Bock said that he shares concern about the use of integrated navigation systems, which allow ships to follow a series of waypoints automatically, using GPS or other inputs. “It’s one thing to use it out in the open ocean where there are miles and miles between you and everything else,” he said. But the problem becomes very different in confined waters. “It takes time to switch over to the manual system; it takes time to get the ship back to that safe position.”

Bock wants to see the proposals before giving any endorsement, but he acknowledged the need to take a look at the issue. “I’d want to see the guidelines before I’d say we’d support them,” he said. “It might make sense to limit the use of that system.”

Ed Goudy, secretary/treasurer of British Columbia Coast Pilots Ltd., said his organization discourages pilots from using automatic navigation systems in confined waters. “Our stated policy is that we don’t use them,” he said. Sometimes systems reliant on GPS for determining a ship’s location have problems, according to Goudy. “You see a lot of instances in which the GPS signal gets dropped.”

The mountainous terrain of the Pacific Northwest can interfere with reception of satellite signals for GPS. Goudy has seen electronic devices plot some unlikely positions. “The position will be over land,” he said.

By Professional Mariner Staff