Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.
Issue link: http://uscgproceedings.epubxp.com/i/665311
50 Proceedings Spring 2016 www.uscg.mil/proceedings MODU Kulluk — The Investigation On December 27, 2012, out in the Gulf of Alaska, the Aiviq was towing the Kulluk astern. 9 Looking out the after wheel- house windows, one of the mates on duty took a cell phone video of the seas and the Kulluk astern on the tow hawser. The video captured the hawser rising up from a somewhat slackened condition until it was almost horizontal to the deck of the Aiviq. It then led from the winch through the sea and swell, leading out to the Kulluk almost a quarter of a mile astern. The downward defection of the towing hawser is called catenary, which is one of the ways marine personnel assess towing operation safety. Correct use of this catenary absorbs the everyday stresses and strains of ocean towing, reducing the cyclic loading on critical equipment. During the voyage, the Aiviq's sophisticated towing winch strain gauge located in the wheelhouse showed the load on the towing equipment. In the cell phone video segment, the strain monitor showed the towing load swinging from 28 tons to 228 tons. The mate commented on the strength of the steel towing wire. From departure to the point where the towing equipment failed, there was near-continuous cyclic loading on the towing equipment. In the late morning of December 27, 2012, the frst in a series of towing gear failures occurred. There would be more gear failures as efforts took place to control the Kulluk in the extreme maritime weather environment of the Gulf of Alaska. At one point, the Aiviq suffered the loss of main engines, generator injector failures, and other issues with maneuvering thrusters while attempting to tow the Kulluk. The Coast Guard investigation focused on, among other things, the SMS in place for the Aiviq and her crew as well as the crew's training, competencies, and qualifcations. The investigators looked for formal or informal policies, procedures, job aids, checklists, and other documentation indicative of how the unique towing operation was to be carried out. Unfortunately, investigators were unable to uncover what constituted a safety management system related to towing operations. During the course of the investigation, it was determined that there was a disconnect as to the role and responsibilities for the towing vessel master and the tow master on the towed vessel Kulluk. A safety management system would have detailed the roles and responsibilities for these personnel, reducing ambiguity in the most critical moments. Additionally, details on the use of the ultra-sophisticated towing winch, used to monitor and trend chart the load on the towing system and monitor the length of the tow- ing hawser, were not discussed in the vessel's operating procedures. The tow system was equipped with alarms for critical events on the vessel, but bridge offcers could not elaborate as to how the alarms and response to those alarms constituted a part of a comprehensive plan for towing the manned tow. On the morning of the initial towing gear failure, there were 38 critical alarms for the towing winch system that indi- cated strains of at least 300 metric tons. The part that ini- tially failed (or was lost) was a shackle with a safe working load of 125 tons. A robust SMS would have indicated how to handle these alarms or would have pointed the reader to the proper place where these strategies could have been found. Without going into all the defciency elements of the towing operations, it would be appropriate to state that a robust and well-written SMS that incorporated lessons learned and In the photo above, the bridge control equipment on the M/ V Delta Mariner, and similar propulsion control equipment aboard the M/ V Aiviq (right). Such complex, sophisticated equipment requires putting a comprehensive safety management system in place so the vessel's crew knows how to operate the systems under all kinds of expected conditions. U.S. Coast Guard photos.