TTS Marine Cranes has completed a major offshore replacement project, managed without the use of shore cranes, saving money for the contractor by ensuring that operations were able to continue without disruption.
Replacing key components for offshore vessels can be an expensive business, not only because of the cost of the project itself, but also because of the money that can be lost while the vessel is out of action. In the case of the floating production storage and offloading (FPSO) vessel Sendje Ceiba, owned by US oil and gas producer Hess Corporation and anchored outside Equatorial Guinea in West Africa, just one day spent off-hire could cost NOK 5 million in lost revenues.
This presented a challenge when it came to replacing the bearings of the vessel’s cranes. FPSO vessels are permanently anchored in the oil fields and never go alongside. “The ship stays out in the open ocean all the time,” explains Leiv Håland, service manager for TTS Marine Cranes division. “This adds complexity to the project, because it’s difficult to get help from outside to do the job. To bring out a floating crane would cost an enormous amount of money, not to mention the losses incurred if the ship went off-hire.”
The bearings that needed to be replaced were among the largest TTS had ever delivered, while the environment of an oil processing vessel was unsuitable for some traditional construction methods: “We replaced the main parts of the cranes out at sea without any help from shore cranes,” says Håland. “The supports we needed at both ends of the crane foundation, for sliding the old bearings out and the new ones in, had to be bolted on. We weren’t able to use hot work, so the team had to do a lot of manual drilling as well as a considerable amount of climbing. It was a very interesting and very complicated job.”
In the first project of its kind for the company, the TTS team was able to lift out the old bearings and replace them with new ones safely, while making considerable cost savings for the customer. “It took about four weeks to replace the bearings, one for each of the two cranes, mainly because we needed to avoid disrupting the vessel’s operation,” explains Håland. “We had to work during routine breaks from production. We were therefore able to save a considerable amount of money, avoiding the risk of an off-hire period during the entire installation.”
