TSB: Confusion, system failures caused ship to ram Canadian frigateJun 1, 2015 12:04 PM
Poor communication between the bridge and engineers was a root cause of a former offshore supply vessel’s propulsion loss that prompted it to strike a moored Canadian navy ship in 2013, investigators said.
American Dynasty, operating as a U.S. commercial fishing vessel, hit the moored HMCS Winnipeg FFH 338 in Esquimalt, British Columbia, on April 23, 2013. The 240-foot commercial ship lost electrical power and propulsion control, veered off course and struck the frigate.
The incident occurred due to insufficient planning between American Dynasty’s master and chief engineer regarding vessel arrival procedures and emergency maneuvering, and the poor crisis communications between the bridge and the engine room, according to a report issued by the U.S. National Transportation Safety Board (NTSB).
Canada’s Transportation Safety Board (TSB), which participated in the joint investigation, found that without procedures and comprehensive emergency drills, crews may not be proficient in taking mitigating action during an emergency.
American Dynasty, owned by American Seafoods Group, was approaching the graving dock at Esquimalt at 0817 when it lost control and hit the moored 440-foot frigate. Both vessels sustained extensive structural damage, and the naval pier required repairs. Six shipyard workers suffered minor injuries.
American Dynasty, a factory stern trawler, departed Seattle on April 22, 2013, for Esquimalt to undergo a scheduled dry-dock inspection before the start of its next fishing season.
Prior to departure, the chief engineer had been using the emergency generator on its harbor mode setting to generate electrical power. While in harbor mode, the emergency generator was not able to automatically start in the event of a power loss. Before American Dynasty departed, the nine-person crew conducted pre-departure tests of the required equipment.
American Dynasty is equipped with two Bergen 4,000-hp main diesel engines connected to a single hydraulically powered, ducted (shrouded) controllable pitch (CP) propeller. The CP system could be controlled from the bridge or from the engine room. The trawler was fitted with a single-tunnel bow thruster in the forward section of the hull. For electrical power, the trawler had two main engine shaft pickup generators, an auxiliary diesel generator and an emergency diesel generator. It had three sets of 24-volt, direct-current emergency batteries.
After embarking a British Columbia Coast Pilot and an apprentice pilot near Vancouver Island at 0710 on April 23, American Dynasty proceeded toward Esquimalt.
According to the NTSB report, the master reduced the CP system to zero-thrust position at 0735 and maintained the vessel’s heading using the bow thruster. At 0805, a docking pilot from Victoria Shipyards boarded American Dynasty from the harbor assist vessel Seaspan Foam, which was then tied to the trawler’s stern. A second harbor assist vessel, Charles H. Cates XX, was tied to the trawler’s port bow. Once both assist vessels were secured, the docking pilot assumed control of American Dynasty. At about 0815, he requested that the master shut off both main engines and the radars to prepare for entering the Esquimalt graving dock.
The master called the engine room and the oiler answered because the chief engineer had stepped out. The master stated that he was transferring propulsion control and then hung up. At 0816, the master transferred the CP control to the engine room.
The oiler had never previously accepted propulsion control, and he consulted with the electrician who advised the oiler to accept the propulsion control by pushing a button on the CP panel.
However, the main engines needed to be shut off, which the master did not communicate and which the oiler did not know. After accepting propulsion control, the oiler left the room and entered the machinery space to stop an ongoing fuel oil transfer. The CP system was set at zero pitch, but both main engines were clutched in and turning the propeller shaft. The vessel’s speed was 1.6 knots.
On the bridge, the master shut off both steering pumps and the bow thruster motor. About 15 seconds after the propulsion control transfer, American Dynasty experienced a complete loss of electrical power. The auxiliary generator was still running, but the breaker that tied the power to the main electrical power bus had been tripped open. At that point, the trawler was about 2,500 feet from the graving dock entrance. The chief engineer and the oiler quickly returned to the engine room when the power loss occurred.
The chief engineer tried to reconnect the auxiliary generator to the main switchboard but was unable to. The emergency generator had not been changed from harbor to emergency mode after leaving Seattle and was not set to provide emergency backup power. The CP control system had also lost power. The trawler’s main engines were still running and turning the propeller shaft.
On the bridge, the British Columbia Coast Pilot noticed that the trawler’s speed was increasing and that the heading was drifting to starboard toward the Canadian Forces Base in Esquimalt. The master noticed propeller wash behind the vessel and tried to call the engine room using the service phone, but it had lost power and was inoperative.
“The master could have used the available sound-powered phone or portable radio to contact the engine room,” the report stated, “but instead asked the chief officer on the bridge to go to the engine room for an update.”
The tugs pulling the trawler saw the directional change and tried to realign the vessel’s course. One tug’s winch broke as American Dynasty pulled away, and the other’s towline parted.
The chief engineer continued his efforts to manually close the breaker connecting the auxiliary generator to the main switchboard to regain electrical power and tried unsuccessfully to close the breakers for both shaft generators to energize the switchboard.
Shortly thereafter, the auxiliary generator shut down. The engineer left the engine room and entered the machinery space to investigate why the auxiliary generator had stopped.
The master ordered the anchor dropped and tried to sound the trawler’s whistle, which had not been tested before leaving Seattle and was nonfunctioning.
“Neither the master nor the pilots tried pressing the main engines’ emergency stop buttons, which were located prominently on the bridge control console. Pressing these buttons would have stopped the propeller shaft from rotating and would have reduced the trawler’s speed,” the NTSB report stated.
As the speed increased to 5 knots and an impact was imminent, the crew abandoned the attempt to use the anchor. At 0817, the bow of American Dynasty struck the port side of Winnipeg. The impact caused the frigate’s stern to pull away from the dock, damaging the vessel’s starboard side as well as Pier 3C. Six shipyard workers aboard Winnipeg sustained minor injuries in the incident.
American Dynasty’s bow shell plating, forepeak tank, chain locker and deck plating were deformed as a result of the impact. The damage was estimated at $450,000.
Accident investigators examined all of the equipment to determine the cause of the power loss. The decrease in electrical load that occurred when the master shut off equipment, such as the bow thruster motor, caused a change in the auxiliary generator’s speed and frequency. This change, in turn, likely caused the generator breaker to trip open on the main switchboard. Ultimately, the auxiliary generator’s diesel engine shut down.
Investigators found a damaged magnetic pickup sensor on the auxiliary generator’s diesel engine. This sensor was supposed to emit a signal to the engine’s speed control unit, allowing controllers to regulate the engine’s speed. If the sensor failed, the engine was designed to shut down. However, investigators discovered that a failsafe feature on the auxiliary generator’s control panel had been disabled with a bypass jumper wire, preventing the engine from shutting down when the sensor failed. It could not be determined when or why the failsafe had been disabled, nor why the auxiliary generator’s engine eventually shut down despite the bypass.
Because the emergency generator was not set to start automatically and accept the electrical load once the auxiliary generator shut down, the trawler’s emergency batteries should then have provided power to the CP control system. However, investigators found that the batteries, which were supposed to automatically supply power to several of the trawler’s essential systems during a power loss, were incapable of holding a sufficient charge. Although the crew kept a log that tracked the testing of the batteries, no established schedule was in place for their maintenance or replacement. All of the batteries had last been replaced in 2009.
Investigators found that the CP system had a leak in the hydraulic oil distribution box, and the actuator allowed hydraulic oil to leak by, which enabled the propeller pitch to be in the ahead direction during a power loss. The CP oil distribution system and seals were scheduled for overhaul during the Esquimalt shipyard period.
American Dynasty’s heading change to starboard was attributed to the trawler’s forward progress with a slight deflection of the rudder of about 2.5 degrees to starboard and a starboard 10-degree bow thruster pitch before the motor was shut off. When the trawler’s speed accelerated, the harbor assist vessels could no longer control the heading.
According to the master’s work/rest/sleep history, he had been working for 16 consecutive hours and had been awake during the entire transit from Seattle to Esquimalt. Further, as relief master, he was not fully familiar with American Dynasty’s bridge equipment, such as the AIS, which he needed assistance to activate. He and the chief engineer had not agreed on an arrival plan with identified risks or contingencies, such as procedures during loss of power to the CP control system.
Finally, although the vessel company had a computerized tracking system for shipboard maintenance, this system did not include procedures or schedules for critical components, such as the batteries and the whistle. The system was based on class requirements for maintenance but did not include original manufacturer recommendations, such as the need to examine the CP hydraulic components at 80,000 hours.
The NTSB said contributing to the accident was the status and condition of American Dynasty’s emergency generator and emergency batteries, which were not prepared to supply power at a critical time.
In its findings, Canada’s TSB report agreed with the details of the NTSB report and found that the loss of electrical power to the actuator valve, the internal oil leak from the oil distribution box, and the hydrodynamic forces acting on the propeller blades caused the pitch to creep in the ahead direction and the vessel’s speed to increase.
Ron Rogness, vice president of corporate relations for American Seafoods Group, told Professional Mariner that because the incident was still a pending legal matter, the company declined to comment.
The TSB report indicated that American Seafoods Company LLC has posted an operating procedure to ensure that the emergency generator is set to start automatically; replaced the nonfunctional set of emergency backup batteries; replaced the magnetic pickup sensor and governor speed control unit; tested the auxiliary generator engine for all alarms and tripping functions; overhauled the pitch control oil distribution box, and replaced the pitch control actuator.
Seaspan, which operates its Victoria Shipyards at the Esquimalt Graving Dock, owned and operated by the Government of Canada, declined to comment.
British Columbia Coast Pilots Ltd. did not respond to a request for comment.