Service operation vessels that have entered service recently and are on order highlight the trend towards designs that combine a high level of operability, low operating costs and logistics innovations
Among the most innovative of service operation vessels (SOVs) currently on order, the Louis Dreyfus Armateurs (LDA) newbuild has a number of features that distinguish it from other examples of the type.
Designed by Salt Ship Design in Norway and being built by Cemre Shipyard in Turkey, LDA’s SOV is the subject of a long-term contract with Dong Energy. It will operate on four offshore windfarms off the German coast – Borkum Riffgrund 1 and 2 and Gode Wind 1 and 2 – providing a base for windfarm technicians.
Due to be delivered by the Turkish yard in the fourth quarter of 2018, the 83.0 m vessel has a beam of 19.4 m and will be equipped with a dynamic motion compensated gangway with what Salt Ship Design describes as “a unique onboard logistic solution”.
LDA worked closely with Salt Ship Design to develop a vessel tailored for the needs of the offshore wind industry. “This has resulted in a very purpose-driven SOV,” said the Norwegian naval architect. “LDA is expanding its range of services in the renewables industry. Its personnel have been working closely with us for a long time to develop a vessel tailored to meet the needs of the offshore wind industry,” a spokesperson for Salt Ship Design said, “in particular, focusing on enhanced operability and efficient logistics. The contract is an important milestone for us because the renewables industry is becoming an increasingly important market.”
The ship will have accommodation for a minimum of 60 windfarm technicians and will provide them with comfortable conditions, including individual cabins, a gym and a cinema. The technicians will be transferred to the wind turbines via a specially designed daughter craft (in case of good weather conditions) and will use the motion compensated gangway in heavy seas. The daughter craft will be capable of transferring eight windfarm technicians and 1 tonne of cargo to a turbine. The motion compensated gangway will have a range of approximately 19 m and will be complemented by a unique motion compensated crane with a lifting capacity of 1 tonne at 23 m.
LDA has opted for the construction of a highly specified vessel that combines a number of innovative ideas, not least in terms of its environmental impact and operating costs, which will both be reduced as a result of the adoption of a hybrid diesel-electric propulsion system combining diesel engines and batteries.
The windfarm service vessel will have a DC power distribution grid that will allow batteries to be integrated into it, making the ship more environmentally friendly and efficient. ABB is installing the DC grid along with what it calls a power and energy management system enabling the generators to run at variable speeds while also charging the batteries.
In a statement about the system, ABB marine and ports global product manager for the Onboard DC Grid John Olav Lindtjørn said “Energy storage can be used for many purposes on board. Sometimes it serves as the sole energy source, but for this windfarm vessel, it is being deployed as an effective supporting element for the main engine.”
The DC grid will integrate two sets of batteries that will be used primarily for spinning reserve and peak shaving so that power peaks during operation can be covered by the battery rather than starting another engine. Battery power can also act as backup for running generators, reducing the need to run spare generator capacity.
The level of operating efficiency available in a hybrid power system reduces wear and tear on engines and significantly increases fuel efficiency at lower loads where, in traditional AC power systems, generators run at a fixed maximum speed regardless of the power demand on board.
Apart from enhancing the ship’s green credentials in the environmentally conscious offshore wind industry, ABB also points to a benefit for the vessel’s crew: reduced vibration when the hybrid system is on battery power.
MAN will supply the 8L21/31 variable-speed gensets for the vessel, which will also feature the company’s EPROX energy-saving electric propulsion system, which will further reduce the vessel’s fuel consumption and emissions. The engines will be prepared for IMO Tier III and set up in such a way that they can be retrofitted at a later date with an SCR system. This is to cater for the possibility that IMO Tier III NOx emission limits could be introduced, without obligation, in NOx emission-control areas in the North and Baltic.
Uptime in Norway will supply the walk-to-work gangway for the LDA newbuild. TTS Group and Ulstein will provide the motion compensated crane. Together, the companies have been awarded a contract for a TTS Colibri motion compensated crane for the SOV. The new crane combines TTS’s expertise in crane design and manufacturing with Ulstein’s expertise in motion technology and analysis.
“Two features make the TTS Colibri unique compared to other solutions in the market,” claimed Ulstein Equipment managing director Gilbert Rezette. “Firstly, the Colibri system is a stand-alone add-on device for a standard offshore crane. It adds functionality, while the crane maintains its functionality as a fully-fledged offshore crane including deepwater subsea capabilities. However, what makes this system truly unique is its groundbreaking anti-sway technology, which also allows it to mitigate wind-induced motions that act directly on the load.
“3D motion compensation technology is not new to the industry and has enabled greater operability for personnel transfer between vessels and fixed offshore platforms through the use of motion compensated gangways,” he said. “However, operations typically require personnel and equipment to be transferred between a vessel and platform. Hence, TTS Colibri is a natural step in enhanced vessel operability, providing motion compensated lifting to match the increased operability offered by motion compensated gangways.”
“Joining forces has enabled both our companies to offer a serious and commercially very attractive alternative in this market segment,” said Carl Herland, sales manager at TTS Offshore Solutions, a subsidiary of TTS Group. “Colibri is suitable for retrofit to existing cranes, making it a viable solution for upgrading cranes that are already in service. Hence, it offers shipowners the ability to enhance the flexibility of their existing fleet.”
Of the SOVs that have recently entered service, one of the most noteworthy is Bibby Marine Services’ Bibby WaveMaster 1. Although primarily intended for the offshore wind industry, this vessel is also well suited to work in the offshore oil and gas industry, as contracts already awarded to the vessel demonstrate. Designed by Damen and built by the Dutch group’s yard in Galaţi, Romania, Bibby WaveMaster 1 completed sea trials in the Black Sea earlier this year and set sail for the UK, where it began work on its first project, supporting offshore construction work on Innogy’s Galloper offshore windfarm off the east coast of England. The vessel was chartered by James Fisher for three months (plus options) of work related to the commissioning of the substation and turbines on the windfarm.
Having completed work on the Galloper windfarm, Bibby WaveMaster 1 will transition into the offshore oil and gas market early in 2018, having clinched a contract from energy group Total supporting gas platform work in the North Sea.
The SOV can accommodate up to 90 workers and crew and has a height-adjustable walk-to-work gangway with a six-stop elevator for 100% stepless access. There is a helideck and daughter craft for various access and support functions.
Launched at Damen Shipyards Galaţi on 24 March 2017, Bibby WaveMaster 1 is an innovative design that has been customised in order to ensure that windfarm technicians – or oil and gas maintenance personnel – can directly access the ship’s gangway from the warehouse areas. The helideck, daughter craft and crew transfer vessel landings (with refuelling) complement the vessel’s versatility.
Damen’s director of business development and market intelligence Peter Robert explained that the focus of the design was on providing safe, comfortable access to far-from-shore windfarms including, in a worst-case scenario, severe central North Sea conditions. This resulted in a vessel capable of providing turbine access in up to 3.1 m significant wave height that is able to remain at sea for periods of up to one month at a time.
Bibby Marine Services Ltd chief executive Stephen Blaikie said the vessel is built around a stable dynamic positioning class 2 platform so it offers a very high level of operability. “It will provide safe offshore transfers for personnel by way of a motion compensated access system. Equipment will be securely transferred by way of a heave compensated offshore-rated knuckleboom crane,” he said.
Mr Blaikie said working efficiency is one of the key drivers behind the design of the vessel. The space inside has been carefully planned in terms of storage, workflow and logistics to ensure that the movement of both people and goods is smartly optimised, and the ship will also be as ‘green’ as possible, with minimal emissions and low fuel consumption.
Comfort is also paramount, and the vessel will have Comfort Class 2 standard accommodation with all of the 60 en-suite berths equipped with TV, wifi and leisure facilities. As well as offering a high standard of living, the vessel hullform has been designed with comfort in mind, ensuring exceptional seakeeping abilities and minimising motion sickness to ensure technicians are fit for work.
Mr Robert describes the new unit as “much more than just a vessel”. He sees it as a “total access and accommodation solution”. He highlighted the fact that its length, breadth and draught all reflect the metocean data they have studied in the area that it is likely to encounter in UK Round 3 projects. “At 90 m, the hull is longer than that of a conventional platform supply vessel as used in the offshore oil and gas sector, from which some SOV designs are derived, and the bow section has been lowered by 1.5 m to create a V shape,” he told OWJ.
“This feature offers significantly reduced slamming and facilitates inclusion and improved offshore operation of the bow thrusters. The aft ship has been adapted specifically to the tasks that the vessel is designed for, including stern to waves operation.”
The most pronounced features that have been included are the strong V shape in the frames in the aft ship to reduce slamming and the concentration of volume in the mid-ship region to achieve a slender aft ship. Mr Robert says both features should make stern-to-weather operations more comfortable than on a vessel derived from a conventional PSV design.
As Mr Robert also explained, ergonomic design sees the interior spaces grouped together into similar task areas. This not only separates ‘clean’ and ‘dirty’ tasks but ensures short lines of communication and eases workflow. The accommodation has been placed in the midships area for additional comfort – the location reducing vertical acceleration by as much as 15%.
MHI Vestas stipulates low fuel consumption for newbuild SOV
MHI Vestas and Esvagt are building on their existing relationship with a fuel-efficient SOV design for the Deutsche Bucht (DeBu) offshore windfarm. The SOV is due to enter service in August 2019. It will operate in support of the DeBu windfarm on a 15-year contract between the companies, which is the longest in Esvagt’s history and its largest in terms of value.
The SOV for the DeBu project will be equipped with a walk-to-work gangway system with a bespoke tower with a crane placed on top of the tower. Together with Esvagt’s Safe Transfer Boats (STBs), they will be used to transfer personnel from the vessel to wind turbines.
Esvagt’s chief operating officer Kristian Ole Jakobsen said “MHI Vestas prioritised a fuel-efficient ship, and we are proud to be able to deliver a vessel of this size with remarkably low energy consumption,” noting that the STBs will be able to make port calls independently of the vessel, thus further reducing its environmental impact.
Havyard, the designer of the vessel, said it will have particularly low levels of fuel consumption thanks to the use of diesel-electric propulsion and a hydrodynamically optimised hullform.