A bridge crew’s inadequate training on emergency procedures in the event of a helm failure led to the grounding of a bulk carrier in the St. Lawrence River in 2011, the Transportation Safety Board (TSB) of Canada said.
Orsula was sailing down-river Dec. 15, 2011, near Trois-Rivieres, Quebec, when the helmsman attempted to make a course correction and the rudder failed to respond. Despite reversing the main engine, the ship ran aground.
Shortly before the grounding, the master, who had been temporarily absent while the ship was under command of the officer on watch, came on the bridge. He went directly to the steering stand and transferred the steering system actuator switch from port to starboard, restoring control to the steering but too late to prevent the grounding, the TSB’s investigative report said.
“Vessels that are compliant with the International Convention for the Safety of Life at Sea (SOLAS) are required to have at least two independent steering control systems, designed so that there is a built-in redundancy,” the TSB wrote. “In this occurrence, when the rudder did not respond, the on-watch personnel did not know why and did not select the alternate steering system. A quick response would have allowed the vessel to regain steering control before it departed the channel and grounded.”
The 656-foot bulk carrier was built in 1996, at Yiangnan Shipyard in China and is owned by Atlantska Plovidba in Dubrovnik, Croatia. The Marshall Islands-flagged vessel is powered by a B&W 6S50MC, two-stroke, single-acting engine, developing 8,562 kW at 127 rpm.
An investigation by an authorized representative of Sperry Marine, manufacturer of Orsula’s steering control system, determined that the port steering system helm potentiometer had failed. As part of the service call, the three potentiometers in the steering stand were replaced, and the system was found to be functional.
The ship is fitted with a direct-drive reversible low-speed engine. The engine drives one fixed-pitch propeller, and the vessel service speed is approximately 15 knots. To switch from ahead to astern movement, the engine must be allowed to slow down to 37 rpm before it can then be set into reverse mode and restarted astern.
When the main engine is set to full ahead (127 rpm) and the vessel’s speed is 14.8 knots, it takes 155 seconds for the engine to set into astern starting mode. In the case of an emergency, the vessel can be stopped in five minutes, 21 seconds.
The TSB determined that when the helm follow-up potentiometer of the port steering system failed, the electrical link between the steering stand and the telemotor in the steering gear compartment ceased to function. Control of rudder movement was lost. At this time, the rudder angle indicator was showing 10° to starboard. Orsula veered to starboard and left the dredged channel when it was intended to alter course to port.
The bridge crewmembers were not familiar with the use of the non-follow-up mode or with switching the steering system selector switch from port to starboard to regain steering control. When the master switched the steering system selector switch from port to starboard, he restored steering control, but it was too late to prevent the vessel from running aground.
The TSB found that without the regular replacement of potentiometers, there is an increased risk that they will fail in service.
The agency noted that crew may be unfamiliar with the steering control methods of the non-follow-up mode or switching steering systems in cases of steering failure if this information is not incorporated into technical manuals, familiarization and drills, or adequately described and posted near the steering stand.
An underwater survey of Orsula revealed two cracks near the bow thruster and long indents on the port and starboard bow. Starboard bulkheads between the bow thruster room and forepeak tank were found buckled and detached at the bottom. Numerous transverse floors were found buckled and detached at the bottom over a length of just over three feet.
Professional Mariner contacted the ship’s owners for comment and did not receive a reply.
The investigation revealed that Orsula’s voyage data recorder (VDR) had not been operating since May of that year — about seven months. When data from the VDR, in particular the bridge audio recordings, are not available to an investigation, this may preclude the identification and communication of safety deficiencies, the TSB said. The board warned the industry to ensure that VDRs are kept in working order.
“The purpose of a voyage data recorder is to create and maintain a secure, retrievable record of information related to the position, movement, physical status, command and control of a vessel,” the TSB report states. “Objective data — voice data in particular — are invaluable to investigators seeking to understand the sequence of events leading up to an occurrence. In this investigation, voice data recorded by VDR would have been a highly effective means of gathering information about the activities of the bridge team.”