VESSEL REVIEW | NOS Impresser – Northern Offshore Services deploys hybrid crewboat in Scottish waters

Sweden's Northern Offshore Services (NOS) has begun operating a new catamaran crewboat at the Neart na Gaoithe offshore wind farm in Scotland. Named NOS Impresser, the vessel is classed by Bureau Veritas and sails under the flag of Denmark.

Recognising the challenging environments and long operations at sea, NOS specified a vessel with comfort in mind through high-quality interior outfitting and furnishing. The design phase for the crewboat focused intensely on efficiency, and NOS expects it will help generate fuel savings of as much as 50 per cent compared to similar vessels currently available.

“We wanted a future-proof platform, considering both efficiency and electrification,” David Kristensson, CEO of NOS’ parent company the Northern Offshore Group, told Baird Maritime. “Our vision is that the vessel can become fully electric in the future without compromising performance.”

Ideal for sustained operations in Northern European waters

Impresser has an aluminium hull, an LOA of 34 metres (110 feet), a beam of 11.2 metres (36.7 feet), an operational draught of only 1.9 metres (6.2 feet), and capacity for 24 technicians and up to 40 tonnes of deck cargo on open fore and aft decks with a total area of 171 square metres (1,840 square feet). NOS’ proprietary high-grip fendering is fitted on the bow.

“The vessel will be used for Northern European trade, transporting wind farm technicians and cargo for the daily maintenance of offshore wind turbines,” added Kristensson. “It is a development of an earlier fifth-generation crewboat that we’ve designed in-house to operate more efficiently, with a focus on performance and sustainability.”

The crewboat has a hybrid electric propulsion arrangement that is prepared to run fully on electricity. The hybrid setup includes two ZEM 94kW batteries and Volvo Penta's upgraded IPS propulsion system, its first commercial installation. It is an integrated helm-to-propeller system, incorporating controls, electronics, custom software, propulsion packages and more, designed to work together seamlessly and reduce errors and inefficiencies.

“The Volvo Penta IPS Professional platform enables us to meet, develop, and enhance our vessels with a focus on both performance and environmental impact,” said Martin Landström, Chief Business Development Officer at NOS. “It’s designed to support our goal of hybridisation, ultimately leading to full electrification.”

Landström added that the "future proof" vessel was also designed to only use the energy needed for specific situations, while a recovery system is fitted to use waste heat generated by the engines.

The four Volvo Penta D13 IMO Tier III-compliant diesel engines each produce 588 kW (789 hp) at 2,250 rpm to propel the crewboat to speeds of up to 30 knots to and from offshore wind farms. The electronics suite meanwhile includes an ECDIS and a radar from Furuno, an Area A1 and A2 GMDSS, CCTV cameras, and a Reygar monitoring system. Cargo will be loaded and unloaded with the aid of a Palfinger Marine PK12002 knuckle boom crane with a maximum lifting capacity of 1,250 kg and a reach of eight metres (26 feet).

Ready for future systems upgrades ensuring longer service life

Impresser is also being operated as a demonstrator vessel. It is equipped with a remote diagnostics package that will capture more than 6,000 hours of data that will be incorporated into optimisation and future Volvo Penta propulsion design.

“The DC grid and electric equipment already installed are ready for future battery upgrades, which will also include offshore charging capability,” said Kristensson. “The deck layout meanwhile ensures enhanced safety in cargo operations and in technician transfers.”

The onboard facilities include six single cabins, a changing and storage room, a coffee lounge, and two toilets. Wifi internet connectivity is also available.

“All the latest technology is used to reduce energy consumption in everything from navigation equipment to lighting and general equipment onboard,” Landström told Baird Maritime. “We also put a strong emphasis on creating the best possible working environment and comfort for the crew, as well as ensuring comfort for the wind farm technicians.”

Impresser has already begun operating in support of activities at an offshore wind farm in Scottish waters.