The Coast Guard issued a safety alert reminding owners and operators of businesses and vessels associated with the towing of large drilling rigs, such as semi-submersibles, conical or other types of non-standard tows, of the importance of planning for such significant towing operations. The alert details the 2012 Kulluk incident and another recent incident with a 17,000-ton semi-submersible drilling rig.
In late 2012, the KULLUK, a conical drilling unit, was under tow from Dutch Harbor, Alaska to Seattle, Washington in heavy weather, when a series of circumstances resulted in the failure of critical towing gear. The primary towing vessel, the AIVIQ, also suffered a loss of propulsion due to contaminated fuel shortly after the initial towing gear failure. As a result, the KULLUK drifted for four days despite many unsuccessful efforts to regain control of the rig. Ultimately the rig grounded off Sitkalidak Island, AK on December 31, 2012.
In early August of this year, a 17,000-ton semi-submersible drilling rig, the TRANSOCEAN WINTER, went hard aground on the west side of the Isle of Lewis, Scotland. While en route from Norway to Malta, its towing line from the vessel ALP FORWARD parted after encountering severe weather. This incident is currently under investigation by the United Kingdom’s Maritime Accident Investigation and it could have similar causal factors to the Alaskan incident.
One recommendation stemming from the United States Coast Guard’s Report of Investigation on the KULLUK incident requested that the federally-chartered Towing Safety Advisory Committee (TSAC) establish a work group to address the issues related to the KULLUK casualty and the towage of mobile offshore drilling units (MODUs) in high latitude environments. TSAC approved the group’s final report at its spring 2016 meeting and delivered it to the Coast Guard on May 17, 2016. Their final report provides valuable information for all organizations and professionals associated with towing large structures at sea such as MODUs.
The final report included background and guidance on the following topics:
• Critical Tows: Describes how to use a simplified risk assessment methodology to analyze aspects of a future tow operation thus establishing future safety and equipment requirements;
• Voyage Planning / Plans (as required by the Code of Federal Regulations): Provides a solid but expandable foundation ensuring consideration of variables capable of impacting an intended operation;
• Tow Procedures: Addresses operational requirements; defines responsibilities of involved parties; and describes equipment parameters, tow motion limitations, and the importance of having key reference material available;
• Towing Gear: Provides information from a technical and analytical perspective on all aspects
of the entire range of tow gear, its identification, selection, testing, etc.;
• Tug and Tow Master: Provides information on the interactions, relationships, and responsibilities for all of the senior persons involved in the towing operation, including the Offshore Installation Manager (OIM);
• Marine Warranty Surveyor: Explores all of the important roles and evaluations this individual
performs in an effort to minimize and eliminate potential risks for the tow; and
• Recommendations: Presents numerous proposals to various entities associated with towing
processes.
These recommendations, together with the content from other sections of the report, collectively serve as an overview of Best Practices for High Risk Towing Operations. The Coast Guard strongly recommends the widest distribution of this information for consideration and inclusion into various Procedural and Safety Management Systems of towing industry associated companies.
Find the final report herebelow
Source & Image credit: USCG
