In 1987, the Heerema H-851 – the largest launch barge in the world – was specially built for positioning the jackets of drilling platforms in the Gulf of Mexico and off the coast of California, USA. Commissioned by Heerema Marine Contracting, the Heerema H-851 was radically transformed earlier this year at the Yiu Lian shipyard in Shekou (China) to make the barge suitable for deck float-overs. With the full service delivery of an Integrated Rapid Ballast System and all the components for modifying the control, Econosto made a major contribution to this high-profile project.
The dimensions of the Heerema H-851 are impressive: 260 metres long, 42 to 63 metres wide, a depth of 15 metres and a displacement of more than 150,000 mT. To make deck float-overs – the positioning of complete, pre-assembled drilling platforms of up to 35,000 tons on jackets already in position in the sea – possible, the barge was narrowed at the Chinese shipyard from the bow over a length of 100 metres from 63 metres to 42 metres. Even after the transformation, the barge can still be used for positioning jackets with a weight of up to 40,000 tons, still making the Heerema H-851 a giant.
Integrated Rapid Ballast System
From a technical perspective, our customer Heerema Marine Contractors also wanted to be able to ballast the barge quicker. Consequently an Econosto Integrated Rapid Ballast System was installed in addition to the existing ballast system with ballast pumps. This system includes a number of remotely controlled butterfly valves installed below the waterline. By opening the butterfly valves, the ballast tanks can be filled at high speed. With the new Integrated Rapid Ballast System, the ballast capacity is 40,000 m3 per hour. For de-ballasting, use is made of the already existing ballast pumps and stripping pumps.
Controls
The existing control of the Heerema H-851 also had to be radically modified and extended in order to comply with the most recent safety requirements. Among other things, parts of the hydraulic system, electrical hardware and software systems were made redundant so that the operational activities would not be placed at risk. Further, all control activities made from the deck container and all measured values are now stored in a logging system.
Electro-technical installations
Finally, the electro-technical installations were modified and expanded. A new back-up board provides extra redundancy in the supplies to various components. Moreover, the existing mimics have been replaced with new mimics, based on the new layout of the barge. At last, in addition to the existing control in the control room, a deck container has been placed from which all components can be controlled and readouts obtained.
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 From top to bottom: drilling platform – Heerema H-851 – jacket
Intensive supervision
The installation of the components and systems supplied by Econosto was carried out by employees of the Chinese shipyard. For commissioning and testing of the systems, however, technicians from Econosto were flown in. It is a remarkable fact that – despite the language barrier – a high degree of solidarity between the Dutch and Chinese workers was observed. Everyone was proud to be able to work on this project. Finally, the sea trials were also carried out to full satisfaction.
Total concept
A deciding factor for getting this extensive project awarded, was Econosto’s ability to provide a total concept: engineering, drawings, valves, actuators, hydraulic and pneumatic components, measurement and control systems, expert supervision during commissioning of the various systems, sea trials and the supply of the required documentation. The final custom design is the result of intensive cooperation between Heerema and Econosto.
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发表于 2012-2-8 15:01
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