|Coast Guard Seaman Gregory Crane and Seaman Nathan Cramer on the cutter Munro assist a victim who had been rescued from the sunken Alaska Ranger. Five other crewmembers were killed in the Bering Sea disaster. (Courtesy U.S. Coast Guard)|
The fish-processing ship Alaska Ranger sank in the Bering Sea in 2008 because of a lack of watertight integrity inside the vessel after it probably lost its rudder, the National Transportation Safety Board (NTSB) has determined.
The accident prompted the NTSB to propose reforms to the way the nation’s fish-factory fleet is regulated.
Five of the head-and-gut ship’s 47 crewmembers were killed when the 189-foot vessel sank March 23, 2008, about 120 nautical miles west of Dutch Harbor, Alaska. The loss of life probably would have been less severe if the vessel hadn’t moved astern as crewmembers were deploying life rafts, the NTSB investigators said.
Witnesses stated that Alaska Ranger’s rudder room filled with water, which leaked through supposedly watertight doors, hatches and deck plates and around pipes. Water poured into the ramp rom a bove the rudder room on the factory deck. Other aft portions of that deck flooded, including the harbor generator room and tool room. Eventually seawater reached the engine room, and the ship sank stern-first.
The vessel’s watertight doors and hatches should have prevented such catastrophic multicompartment flooding, the investigators said. The NTSB concluded that refrigeration pipes were not watertight, and some watertight doors failed or were never secured on the Fishing Company of Alaska ship.
“The probable cause of the sinking of the Alaska Ranger was uncontrolled, progressive flooding due to a lack of internal watertight integrity and to a breach of the hull’s watertight envelope, likely caused by a physical rudder loss,” the NTSB report said.
“Contributing to the loss of life was the vessel’s movement astern, which likely accelerated the flooding and caused the life rafts to swing out of reach of many crewmembers,” the investigators added in their September 2009 report.
The NTSB said the vessel moved astern during the evacuation because the ship lost electrical power, causing it also to lose hydraulic pressure. The controllable-pitch propellers are directed by high-volume hydraulic pumps and tend to behave erratically when the pumps are disabled.
The controllable-pitch (CP) propeller system on Alaska Ranger was powered by the main switchboard only. The CP system formerly had a standby hydraulic pump powered by the main engines, but in 1989 the Fishing Company of Alaska’s engineering firm replaced the shaft-driven pumps with electrically driven pumps, the NTSB said.
The master told the night-watch assistant engineer that he wanted to avoid leaving the vessel dead in the water. Still, it would have been preferable to cut engine power when the ability to control the CP system was lost, the NTSB determined.
The astern movement probably forced more seawater through the rudder room, and it caused the ship to move away from floating life rafts. The crew jumped into the icy water.
“Slowing or stopping the main engines would have arrested the vessel’s astern motion, which might have slowed the flooding as well as prevented the life rafts from deploying out of reach,” the report said. “The Alaska Ranger would not have traveled astern if the vessel’s controllable-pitch propeller system had been equipped (as it originally was) with hydraulic pumps driven off the main propulsion shafts,” the report said.
In July 2008, the U.S. Coast Guard issued a safety alert warning operators to review their controllable-pitch propellers to ensure they understand their operation.
“The NTSB is concerned that, like the Alaska Ranger, other U.S. vessels could be equipped with controllable-pitch propeller systems whose hydraulic pumps lack a fully redundant power system and could thus experience an uncommanded and potentially dangerous change in direction of speed if the pumps were to lose power,” the latest report said.
Alaska Ranger was not required to have a chief engineer on board. Because it did have one, that person was required to be Coast Guard-licensed. The vessel’s chief engineer held a license to serve as engineer on fishing vessels of not more than 6,000 hp. Alaska Ranger’s maximum horsepower was 7,000, so the chief engineer was not authorized to serve on that vessel, the NTSB said. Neither of the two assistant engineers were properly licensed for their duties either.
Fishing Company of Alaska was under the mistaken impression that Alaska Ranger had been approved for voyages through ice when actually it hadn’t been ice-classed.
The board recommended that the Coast Guard seek legislative authority to assume more responsibility for safety practices aboard such ships.
“The NTSB believes that commercial fishing vessels should be given the same safety oversight as inspected vessels,” the report said.
Alaska Ranger was a converted Gulf of Mexico oil service vessel. Crew and former crew complained that the 36-year-old ship, like other vessels in the head-and-gut fleet, was not in prime condition. At the time it sank, Alaska Ranger’s operator was seeking an extension for compliance with a Coast Guard program meant to improve the watertight integrity of more than 50 fish-factory ships. Witnesses said old boats continue working because federal fisheries officials don’t allow companies to replace them and transfer their fish quota. The NTSB report recommends that the so-called Amendment 80 operators be allowed to replace a vessel for reasons other than the loss of a vessel.
Fishing Company of Alaska, based in Seattle, said engineers have inspected the internal watertight integrity of the six remaining vessels in its fleet. The engineers recommended improvements to watertight doors, hatches and bulkheads. The company completed the work in time for the 2009 fishing season.
Tests revealed no illegal drug or alcohol use by ship officers at the time of the accident. Still, the NTSB said Fishing Company of Alaska should review its drug and alcohol policy enforcement, because crew reported that alcohol use was common on the ship, even though the company claimed to have zero tolerance. Some crewmembers were never properly tested on the day of the rescue.