FPSO and marine integrity management and repair specialists Marine Technical Limits (MTL), has recently concluded a project to repair a retaining ring to a FPSO rudder, which was on-station and in production.
The firm, which is based in Kintore, Aberdeenshire, was contracted by an international client to assist in the delivery of this project which is of an “extremely remote and exposed” nature.
Adam Westwell, Marine Technical Limits, Projects Team Lead, said: “At MTL we are experts in all aspects of marine and FPSO hull repair and maintenance management. We pride ourselves on our ability to plan and engineer repairs for challenging projects, and this project certainly provided a few challenges.”
The rudder of a ship is used for steering, and as such, the rudder is typically completely submerged beneath the waterline. For this project to be feasible, the vessel needed to be fully offloaded and very carefully ballasted to raise the top of the rudder clear of the waterline. The weather also needed to be virtually flat calm for at least 3 days , with the weather in the days and weeks leading up to the offload not providing a great level of confidence. Then the stars aligned; the offload was completed, and the weather forecast improved significantly.
“The offload was completed and the team managed to get the worksite set-up with the bespoke staging platform which was designed and fully fabricated in-house. With the worksite finally accessible, the team got their first opportunity to assess the existing retaining ring. Unfortunately, due to conflicting as-built information and the worksite location not allowing a pre-mobilisation site survey, the replacement retaining ring had been fabricated based on some broad assumptions. The repair team immediately confirmed that the existing ring had 12 bolts, not the 8 which had been accounted for in our replacement ring. It was Saturday evening, the vessel was continuing to produce causing the rudder blade to slowly submerge beneath the waterline, and we knew the weather window wouldn’t last forever.”
The team at MTL worked tirelessly to deliver a solution which would meet the expectations of the client and be delivered in time. A new fabrication drawing was produced, and with the immediate support of their fabrication sub-contractor, they managed to have the replacement ring fabricated and delivered to the vessel in good time.
Adam added: “With the extremely remote and dangerous nature of the work location (overside working at splashzone), the completion of this scope is a real testament to the success of the onshore planning and safety engineering, and the dedication of the offshore personnel to deliver this scope safely.
MTL is a specialist FPSO integrity and repair management company, providing structural integrity management, on-station FPSO repair, naval architectural and equipment solutions. MTL’s unique approach to delivering safety, value and quality is founded upon a deep understanding of the specific needs of FPSO operators and the motivation to find the best solution for their clients.