TSB: B.C. ferry crashed after officers failed to test propeller

The bridge team’s lack of adherence to procedures and unfamiliarity with the operation of the propulsion system in an emergency led to a docking crash of a British Columbia ferry in 2011, the Transportation Safety Board  (TSB) of Canada has determined.

Crew and passengers suffered minor injuries in the accident involving the 520-foot Coastal Inspiration. There was extensive damage to both the BC Ferries vessel and the terminal.

At approximately 1450 on Dec. 20, 2011, the bow propulsion pitch control on Coastal Inspiration failed to respond while the vessel was approaching the Duke Point ferry terminal in Nanaimo, British Columbia. As a result, the ferry struck the berth at an approximate speed of 5 knots.

The 21,777-ton ferry has two modes of propulsion. Mode 1 is used when the vessel has completed maneuvering and is underway. The stern-drive motor uses the power generated by three engines to turn the propeller, which thrusts ahead in the direction of travel. During the passage, the bow propeller is in a feathered position and the forward rudder is locked in mid-ship position.

Mode 2 is used during berthing, unberthing and tight-quarters maneuvering. It uses a minimum of three engines to both drive motors, with each drive motor providing power to its respective propeller. The amount of power supplied to each propeller can be controlled by adjusting the corresponding blade pitch.

There are several ways to control the pitch of both propellers: normal operation, remote emergency pitch control and local emergency pitch control.

The TSB investigation found that procedures for testing the propulsion-control equipment before berthing were not followed. As Coastal Inspiration approached the berth in Nanaimo, a malfunction in the controls went undetected until too late. The investigation found that the vessel’s bridge crew was unfamiliar with the operation of this control in an emergency.

“The bow propeller was engaged but not tested as required prior to arrival, which precluded the bridge team from realizing that the pitch control was not functioning,” the TSB report stated. “The bow propeller pitch control was used once the vessel was at the abort position, in close proximity to the berth, limiting the time for the bridge team to react when it did not respond.”

An isolating amplifier in the propulsion switchboard malfunctioned, causing the overload protection system to activate. This prevented the electronic signal from the pitch control handle from adjusting the pitch on the bow propeller.

“The bridge team did not switch from normal to emergency mode. As the mode was not set to ‘Emergency,’ the master’s attempts to engage the ‘pitch ahead’ and ‘pitch astern’ push buttons were ineffective at regaining control of the pitch,” the TSB noted. “Without the braking effect of the bow propeller, and with the astern propeller providing thrust ahead, the vessel struck the berth at a speed of approximately 5 knots.”

The TSB determined that if the bridge team does not participate in regular drills addressing malfunctions of the propulsion system, it may not be proficient in taking mitigating action during an emergency.

In addition, the TSB said if safety-critical equipment essential for a key operation is not tested before its use, the crew may have reduced time to react in the event the equipment fails to respond.

Deborah Marshall, a spokeswoman for BC Ferries, told Professional Mariner that the TSB’s findings were very similar to BC Ferries’ own investigation into the incident in early 2012.

BC Ferries concluded the root cause of the hard landing was an electronic component failure within the propulsion control system. After the failure, secondary backup procedures were not executed properly.

BC Ferries has implemented procedures, drills and alarms to enhance safety as a result of the incident. An audible alarm sounds in the engine room if a pitch failure occurs — in addition to the visual alarm on the bridge. Critical failure response drills have been developed to ensure contingency plans are exercised. Arrival procedures have been elaborated to include verification of systems earlier to allow more time to react to unusual situations.

By Professional Mariner Staff