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Semi-submersible heavy lifters will be economic and environmentally friendly

Mon 11 Sep 2017

Semi-submersible heavy lifters will be economic and environmentally friendly
OOS Serooskerke and sister vessel will be capable of tandem lifts of up to 4,400 tonnes

In early 2019 OOS International in The Netherlands plans to take delivery of the first of a pair of innovative semi-submersible crane vessels intended for heavy lifting projects worldwide


The semi-submersible lifters, OOS Serooskerke and OOS Walcheren, are under construction at China Merchants Heavy Industry in Jiangsu, China and have a number of interesting features such as a brace-less design and asymmetric pontoons that will enable them to reach a speed up to 12 knots. A steel cutting ceremony for OOS Serooskerke took place in June 2017 and a steel cutting ceremony for OOS Walcheren is due to take place in a few months.

Leon Overdulve, founder and owner of Holding OOS International Group BV, said each of the new vessels will be fitted with two heavy lift cranes with a combined lifting capacity of 4,400 tonnes when working in tandem. The heavy lift cranes will be provided by Huisman Equipment and will be utilised for decommissioning structures in the offshore oil and gas industry, and for installation of foundations, moorings and platforms for offshore wind structures.

OOS said the semi-submersible crane vessels will combine hotel and heavy lift capability. The company said the technical and commercial benefits of this approach have already been proven with the company’s first unit of this type, OOS Gretha, which is working for Petrobras in Brazil.

The dynamic positioning (DP) class 3 crane vessel/accommodation units will have a huge open deck which will be reinforced to take large pieces of equipment. Mr Overdulve said the new semi-submersibles will also be very ‘green’ vessels with SCRs for exhaust gas cleaning, ballast water treatment systems and ENVIRO-OS (environmental protection – offshore plus from classification society ABS ) and green passport class notation.

In keeping with their role as heavy lifters the newbuilds will have a fast, air-driven ballast system for use when handling loads and will provide subsea construction and subsea support to a water depth of 3,000m.

Another important feature of the semi-submersible hullform is that it will provide excellent motion characteristics. Others include the fact that the new units will, the company claims, have lower operating costs than other similar designs, and use around 25% less fuel in DP and transit than comparable designs.

Kongsberg Maritime has been awarded contracts to supply integrated ship systems for the heavy lifters. The contracts, worth more than US$62 million, include supply and integration of the electrical, communications and integrated control systems for OOS Serooskerke and OOS Walcheren. The contracts also include project management, interface management and engineering services at all stages of construction of the semi-submersibles. The company will supply switchboards, frequency converters, automation, navigation and DP systems, as well as radio and satellite communications. Other elements of the contract include networking and onboard entertainment, safety technology and monitoring systems such as an environmental monitoring system.

More recently Mr Overdulve has also started a new company, OOS Drilling BV, which plans to make use of another new vessel type, OOS Luctor et Emergo, which will he said would have “new features providing significant benefits to operators in the offshore oil and gas sector.”

OOS Drilling plans to focus on the growing offshore decommissioning market. “Well plugging and abandonment is the most expensive part of the decommissioning process, not only in terms of technical complexity but also the time required to accomplish this activity,” he told a recent conference. “It is our aim to facilitate faster, easier and more cost-efficient solutions for dismantling old platforms.”


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