The ship owner Acta Marine has already signed a long-term contract for a 12-year basis with RWE to support the day-to-day operations and maintenance of two of RWE's largest offshore wind projects, the newly operational 857 MW Triton Knoll and the 1.4 GW Sofia offshore wind farm which is now under construction in the UK. The vessels are expected to begin operation from the Port of Grimsby in early 2025 and 2026.
According to Tersan's schedule, the two vessels are planned for deliveries in Q4 of 2024 and Q1 of 2025.
Why is the TWIN X-STERN perfect for offshore wind service operations?
The TWIN X-STERN vessels have two sterns and two main propeller units at each end. Placing either end towards the weather results in excellent operability without limitation on vessel speed. The TWIN X-STERN solution leads to improved fuel efficiency whilst reducing the motions, which is important for technicians who need quality rest to perform safe operations.
The TWIN X-STERN offers larger flexibility regarding the choice of propeller type, a bi-symmetric hull shape and propulsion setup with fewer propulsion units is possible.
Hybrid-powered, with green methanol as the primary source of energy
The hybrid power solution in these vessels, with green methanol intended as the main energy source, has dual-fuel engines supported by a battery package. The system integration allows the most fuel-efficient modes of operation. Combining the fuel-efficient TWIN X-STERN and the dual-fuel methanol/diesel power generators will help reduce the emissions in offshore wind farm operations.
Tomorrow's solutions for sustainable marine operations
"We, as Tersan Shipyard, have ensured a really good start of cooperation with Ulstein Design and gained an effective experience with the first two Acta Marine vessels. Ulstein's innovative design solutions on Acta Marine vessels also correspond perfectly with the substantial experience of Tersan Shipyard among different kinds of vessels," said Sakir Erdoğan, Tersan Shipyard Business Development and Marketing Director.
"We are excited to announce the order of two more Ulstein-designed SX216 SOVs," stated Rob Boer, Managing Director of Acta Marine. "These vessels represent the culmination of extensive research by Acta Marine in combination with Ulstein's engineering excellence. With the vessel's advanced features and cutting-edge technology, they will play a pivotal role in supporting the TK and Sofia projects for RWE, providing efficient and reliable services while minimizing environmental impact."
"Ulstein's vision is to create tomorrow's solutions for sustainable marine operations. Through our dedication to innovation, application of expertise and commitment to quality, we give our customers added value. Acta Marine is strongly committed to reducing its carbon footprint, and these CSOVs fit in their timeline towards their goal of a 70 per cent reduction in net CO2 emissions. Achieving a low carbon or zero emission shipping industry in the future, we must act whilst in the design phase of the vessels," says Rolf-Petter Almli in Ulstein Design & Solutions AS.
"Therefore, we worked with Acta Marine to evaluate the best possible fuel alternatives. Methanol's energy density and storage are favourable, it is an accessible energy source, and dual-fuel engines that can handle both methanol and diesel are available in the market. As soon as methanol had been chosen as an alternative energy source, Ulstein Design & Solutions started to adapt the design, implementing the methanol bunkering, tank and system layouts on a conceptual level."
The ULSTEIN SX216 CSOV design
The offshore wind service vessel designs from Ulstein have been developed to effectively support the commissioning, operation and maintenance of offshore wind farms.
The SX216 vessel has a length of 89,9m, a beam of 19,2m and accommodates up to 135 POB. It has a walk-to-work (W2W) motion-compensated gangway for safe personnel transfer to the turbines, a 3D-motion-compensated crane for cargo transfer, and it can carry a daughter craft for in-farm transfers.
Ulstein was appointed Industrial Design Company of the Year 2022 due to its recent innovations to help decarbonise the maritime industry, of which the TWIN X-STERN is one.