Jul 302014
 

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westerntuggerTug tows generate such immense forces that when something goes wrong it goes very wrong and often tragically.In the case of Western Tugger a deckhand suffered fatal injuries while trying to release a tow wire attached to a capsized barge in a report from TSB Canada.

This was the third time that Western Tugger had towed the barge Arctic Lift I. This time the welded steel barge was loaded with rebar and bundled wood and the voyage went without problems for the next six days.

On 10 May at 0400, the mate on watch verified visually that the barge was towing normally.Footnote 10 Shortly after that, heavy fog rolled in, and the mate was unable to see the barge again during the watch. The master arrived on the bridge at about 0545, but was unable to see the barge. The mate left the bridge shortly after the master took over the watch.

Shortly after that, heavy fog rolled in, and the mate was unable to see the barge again during the watch. The master arrived on the bridge at about 0545, but was unable to see the barge. The mate left the bridge shortly after the master took over the watch.

At 0615, when the fog cleared somewhat, the master saw that the Arctic Lift I had acquired a large starboard list and immediately reduced power on the Western Tugger. The deckhand on watch with the master went to the winch room to loosen the nut used to tighten the secondary brake, and the second engineer stood by the winch controls to release them as required.

At about 0620, the bow of the barge rose out of the water and, as the barge capsized to starboard, the entire length of submerged tow wire was lifted out of the water. When the strain came on the winch, it shattered the secondary brake drum. Shards of the brake drum were projected into the forward area of the winch room and struck the deckhand.

The second engineer and other crew members were alerted by the loud noise of the drum shattering and immediately came to the aid of the deckhand. The crew administered first aid, while the master called Marine Communication and Traffic Services Port aux Basques to request medical assistance. The radio medical doctor recommended a helicopter medical evacuation for the patient. A search-and-rescue helicopter was on scene at about 0930, and the injured crew member was airlifted to the hospital in Stephenville, NL. However, the crew member died before arrival at the hospital.

Shortly after that, heavy fog rolled in, and the mate was unable to see the barge again during the watch. The master arrived on the bridge at about 0545, but was unable to see the barge. The mate left the bridge shortly after the master took over the watch.

At 0615, when the fog cleared somewhat, the master saw that the Arctic Lift I had acquired a large starboard list and immediately reduced power on the Western Tugger. The deckhand on watch with the master went to the winch room to loosen the nut used to tighten the secondary brake, and the second engineer stood by the winch controls to release them as required.

At about 0620, the bow of the barge rose out of the water and, as the barge capsized to starboard, the entire length of submerged tow wire was lifted out of the water. When the strain came on the winch, it shattered the secondary brake drum. Shards of the brake drum were projected into the forward area of the winch room and struck the deckhand.

The second engineer and other crew members were alerted by the loud noise of the drum shattering and immediately came to the aid of the deckhand. The crew administered first aid, while the master called Marine Communication and Traffic Services Port aux Basques to request medical assistance. The radio medical doctor recommended a helicopter medical evacuation for the patient. A search-and-rescue helicopter was on scene at about 0930, and the injured crew member was airlifted to the hospital in Stephenville, NL. However, the crew member died before arrival at the hospital.

Arctic Lift I, before departure

Arctic Lift I, before departure

It was not the first time Arctic Lift I had capsized. On 29 October 2006, then known as OTM 3072, it was carrying a cargo of bulk wood chips and was under tow by the tug Ocean Foxtrot when it capsized while in a strong gale about 6 nautical miles north of Bas-Caraquet, New Brunswick. There were no injuries, but the barge was declared a constructive total loss.No stability calculations had been made for the barge prior to departure, the OTM 3072 was regularly loaded to the extent that the load line was submerged, and the stability of the barge was a factor in the capsizing.

Between 1998 and 2013, there were 27 capsizings, including this one, involving barges reported to the TSB. The majority of these were due to 1 or more of the following factors:

  • limited transverse stability resulting from improper loading,
  • a loss of transverse stability in rough weather,
  • downflooding of 1 or more of the watertight compartments, and
  • improper cargo stowage.

On 10 May, the Arctic Lift I developed a large list while being towed by the Western Tugger. This list may have been the result of several factors. Given the barge’s minimal freeboard, the aft deck edge was frequently submerged, allowing water to be shipped on deck. Shipped water may have created a free surface effect on deck and may have downflooded through hatches that were not adequately sealed, creating a free surface effect within the compartments as well. It is also possible that the list occurred because the barge was damaged en route, resulting in water ingress, or because the unsecured cargo had shifted, affecting the barge’s stability.

Although the vessel had an emergency tow release, it could not be activated from the wheelhouse due to the nut-and-bolt assembly on the secondary brake. As such, the master requested that the deckhand go to the winch room and stand by to loosen the nut. Moments later, the forward end of the barge rose out of the water and the barge capsized. The resulting strain on the secondary brake drum caused it to shatter, and parts of it hit and fatally injured the deckhand.

Hazards associated with towing operations may include girding, capsizing, or sinking of the tow; any one of these situations puts the towing vessel at risk. As required by the Hull Construction Regulations, towing vessels are required to be fitted with an emergency tow release that can be operated immediately from the steering position.

The remote release on the Western Tugger was unable to function as intended because of the nut-and-bolt assembly on the secondary brake drum. The installation of a nut-and-bolt assembly required a crew member to enter the winch room and manually loosen the nut before the winch drum would pay out the tow wire, rendering the emergency tow release ineffective. This practice introduced a hazard to operations, which was not identified or mitigated.

Says TSB Caada: ”

“On the Western Tugger, although an SMS was under development, it had not been implemented before the occurrence. Had a formal risk assessment process been in place, it might have identified the following potential hazards prior to sailing:

  • an emergency tow release that was not capable of being operated immediately,
  • hatches that were not reliably watertight,
  • minimal freeboard, and
  • cargo that was unsecured.

Given that the tug and barge had made successful voyages under similar conditions, it is possible that these risks had become normalized through repetition and that, with the completion of each successful voyage, the perception of the severity of each risk had decreased.”

If a vessel operator does not have a safety management system that includes a process for ongoing risk assessments, there is an increased risk that operational hazards will not be identified and mitigating measures will not be proactively implemented.”

The findings of the invetiagtion were:

  1. If an assessment of a vessel’s stability and its loaded condition does not take into account the environmental conditions likely to be encountered on the voyage, there is a risk of the vessel being unfit for the intended voyage.
  2. If a tug’s emergency tow release cannot be activated immediately, the vessel and its crew are at increased risk during an emergency.
  3. If a vessel operator does not have a safety management system that includes a process for ongoing risk assessments, there is an increased risk that operational hazards will not be identified and mitigating measures will not be proactively implemented.
  4. If certain types of unmanned barges in Canada continue to operate outside of a regulatory framework, there is a risk of these vessels being operated beyond their structural and stability limits.

Download TSB Canada report

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