The concept of using vessels as hotels, or floatels, accommodation vessels, or recently, SOVs, or whatever name you give them, has been available in the market for a while. With some of the current and more future projects being built further at sea in harsher sea states this concept is now gaining ‘ground’. Not only do the existing vessels, mainly converted ferries, continue to help out at wind farms, either during construction, or later, in the O&M phase, new designs specifically optimised for these wind farms further offshore are now also being introduced.

Chevalier Floatels & C-bed

Several companies such as C-bed Floating Hotels and Comfort at Sea have already had their vessels chartered to serve as an accommodation vessel for offshore technicians at offshore wind farms for some time.


One of the first companies to ‘introduce’ this concept is C-bed Floating Hotels. The company has been involved since 2008. Offshore WIND spoke to Mr Flemming Hjorth, Senior Sales Executive at C-bed at the EWEA Offshore event in March to catch up since we wrote about them in 2012. At that time C-bed had 2 floatels in operation, the Wind Solution and Wind Ambition. The vessels can stay out at sea for up to a month at a time. All three vessels are flagged in the UK, representing the highest standards. Since we spoke a third one, the Wind Perfection, was added to their fleet. C-bed manages their fleet themselves. The accommodation options range from 100 to 300 plus single cabins, depending on the vessel. The passengers are transferred to the turbines by means of CTVs. Mr Hjorth: “We and our clients are considering our vessels as an offshore project base camp.” C-bed is following the developments and intend to enter the market of smaller types of offshore accommodation vessels too. When asked whether there have been any developments in the past few years Mr Hjorth replied that there has been more need for additional comfort and privacy for the technicians and engineers on board. In order to reply to that demand the Wind Solution was revamped in 2014, adding 20 additional cabins, all single cabins. Additional improvements included in-cabin video systems, new beds and showers. In addition to meeting rooms for relaxation the vessels have a game room, cinema, TV lounge and fitness room on board.

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When asked whether there is a kind of minimum distance from the port after which a floatel would become a more economic solution he replies that it does not necessarily depend on the distance from the wind farm to the port but more to the nearest hotel. “The people that go out to the wind farm on a daily base in CTVs will have to stay overnight at a hotel. There are, however, not always enough hotels available at a port.” It is then that a floatel could already quickly become a good alternative.

Chevalier Floatels

Offshore WIND also spoke to Marcel Roelofs, owner of Chevalier Floatels bv. The company currently owns a fleet of 7 vessels, 4 accommodation barges (of which one is rated the most luxurious hotel barge), a flat pontoon barge and, in the offshore wind industry, 2 DP accommodation ‘walk-to-work’ vessels. Mr Roelofs owned already accommodation vessels. When in 2009 he sold these vessels, he decided to set up a new business. At that time the ‘walk-to-work’ concept was already discussed in the offshore wind industry, and the demand was real. But with the industry still in an immature phase, there were no guarantees for a return of investments with capital intensive projects such as designing and building new vessels. No one really dared to take on the adventure and Mr Roelofs was no exception. However, instead of leaving the concept he started looking at existing vessels that could be converted into accommodation vessels.

He found a Swedish company that owned two ferries that had served as luxury floating restaurants with duty free shopping for tobacco and alcohol but with a change in Swedish Law this business had become less profitable and the vessels were now up for sale. “We were very lucky, here we found 2 ferries, top of the range for comfort and luxury, complying to the Passengers code and which had only served for 1 and 2 years!” Beside this, they had a huge advantage above other vessels, they were equipped with azimuth thrusters, making DP easier.

There were alterations required before the vessels were made completely suitable for serving as accommodation able to remain offshore in a wind farm for a longer period with technical staff being able to walk over to the turbines.

Detailed engineering went into the refit design of the vessels. For an access system the company decided on a motion compensated Ampelmann gangway system. Initially planned to be placed on the aft deck it was later decided to place these higher on the vessels with the advantage that it would have a greater arc of use. For each vessel 48 cabins were created, offering berths for 60 persons. In general 16 beds are needed for the vessel crew and another 4 for the operators of an access system, the remaining berths can be used by the client. All cabins are equipped with their own TV and Wi-Fi connection. A fitness, smoking and lounge area and entertainment system provide additional recreation for the crew and technicians while based offshore.

Mr Roelofs: “In research carried out by Shell it was revealed that for crew  and technicians on board a vessel there are 3 main criteria that would define the comfort of their stay at sea: the quality of the accommodation units and the quality of the catering and, more recently the availability of internet. We have made sure that all 3 criteria are ticked on our vessels, we offer the same standards as a 4-star hotel.” He adds that this is reflected in the way his crew is treating the vessels, “we have a high crew retention rate, they are proud of the vessels and feel responsible for them, and actually help in keeping the vessel up to standard and at the same time provide suggestions for improvements”. The vessels also have 120m2 free deck space and internal storage space and a small heave compensated crane. They can stay up to 30 days at sea but in practise they are often used in a 15 day rotation, returning to port after 14 days.

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Initially Chevalier Floatels planned the conversion of one vessel. This work was carried out by Holland Shipyard. This vessel was renamed DP Gezina, and went straight on her first charter contract to DanTysk for cable support with Van Oord. The interest was so great that the order to convert the second vessel came soon after. On completion of the refit the renamed DP Gallina sailed to her first assignment on Greater Gabbard. Only 2 years later the DP Gezina and DP Gallina have built up a track record of around 10 offshore wind farms to date. At the moment the DP Gezina is working on Butendiek and the DP Gallina will soon start for Alstom in German waters. When the opportunity arises they are also used in other offshore energy markets.

Offshore WIND asked whether, few years later now, would he now consider buying a new build? “Up to now the contracts are still done on a case by case base. We can tell however that the offshore wind maintenance industry is maturing and stabilising and accommodation comfort is becoming more important. At the moment an investment for a new build is still risky, if we were to consider a new vessel we would probably still go for converting an existing vessel again, perhaps with more accommodation space.”

Siemens Wind Power Service & ESVAGT

Siemens is one of the first companies in the offshore wind industry to provide completely new designed, purpose-built service operation vessels for the offshore wind service. The innovative vessels were developed by Siemens & ESVAGT to help lower the costs associated with wind energy by providing accelerated response times and safer working conditions for servicing more complex, far shore wind farms.

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The so-called Service Operation Vessel (SOV) is designed to reduce the technician travelling time to and from the wind farm and optimise the safety and comfort of the technicians, therefore significantly increasing the working hours at the turbines and resulting in a higher efficiency in the O&M work. They also allow work to be performed in a wider range of weather conditions to extend service availability.

The company decided to work with ESVAGT for the design and construction of the two first of these vessels. ESVAGT looks back on 20 years of shipbuilding experience. Their main goal: making the sea a safe place to work. ESVAGT has built over 40 vessels, mainly emergency response rescue vessels, but it is the first time that ESVAGT has built this type of vessel. The vessel design combines the company’s shipbuilding experience and Siemens’s new way of thinking and focus on innovation, sharing the values of safety, quality and performance. ESVAGT and Siemens signed the contract for the two vessels back in 2013. The hulls were built at the Cemre shipyard in Turkey and final fitting took place at the Havyard shipyard in Leirvik in Norway.

The 83.70 metre DP2 vessels are Comfort Class 2 and equipped with an anti-rolling concept for stability and with Siemens’ fuel saving BlueDrive Plus propulsion system. This direct current system enables the engines to work according the requested load rather than on continuous revolutions.

ESVAGT has taken an overall look at energy saving technologies including, for example, the recycling of waste heat from the diesel engines.

The vessels have room for 60 persons, extensive spare parts storage in the under deck warehouse and workshops and will be able to stay at sea for up to 4 weeks. They have 60 single cabins, 40 for the Siemens technicians and the remaining for the ESVAGT crew and possible visitors. It was made sure that each cabin has a window with sea view allowing daylight and minimising sea sickness. Two cinema rooms, a fitness room and a day room provide relaxation for the crews between working shifts during their stay on board. A conference room with space for 30 persons will be used each morning by the Siemens technicians and the site manager to go through their daily schedule and the ESVAGT crew will meet here weekly.

Christening ESVAGT Froude

On 23 June the official Christening of the first SOV for Siemens, the ESVAGT Froude, took place in the port of Rostock-Warnemünde, Germany. Offshore WIND and other press were invited for the ceremony which would be followed by a demonstration trip on this new vessel. The press tour started with opening speeches by spokesmen from Siemens Wind Power Service, The Ministry for Energy, Infrastructure and Development of the State of Mecklenburg-Vorpommern, ESVAGT, and EnBW Energie Baden Württemberg.

EnBW is, together with wpd offshore, the first to implement these newly designed vessels for the O&M phase in their wind farms. The ESVAGT Froude was ordered for operation in EnBW’s Baltic II wind farm. However, the vessel was delivered while the wind farm was not yet in operation. Therefore the ESVAGT Froude gained its first experience at the Westermost Rough wind farm in the UK during its construction phase for turbine commission work before going into service in the Baltic Sea.

OW23_single page 24 5The naming and Christening ceremony was performed by the wife of René Wigmans, Head of Maritime & Aviation Solutions at Siemens, who came up with the name ESVAGT Froude, named after William Froude, a British engineer who developed a method for optimising ship hulls for the lowest water resistance. After the champaign bottle successfully smashed the vessel we shared a lunch followed by putting on our PPE (Personal Protective Equipment) before entering the vessel for the four hour vessel demonstration on the waters outside the Rostock-Warnemünde harbour.

The one thing you noticed straight away, beside the stability of the vessel, is the detailed attention paid to the interior design of the living spaces. The interior clearly left a signature of Norwegian craft work. This eye for detail and quality is not just restricted to the cabins and shared living spaces. It is also clearly visible in all the shared spaces such as the finishing of the walls in the hallways and the wooden floors. A local school was asked to provide the art for the interior of the vessel. The theme was random, as long as it was not maritime related. The result – colourful paintings which would make you wonder whether you were still on a vessel. Another detail that did not go unnoticed – the choice for windows stretching down to the floor. It was explained that these larger windows were designed not just for cosmetic purposes but actually help provide a more stable feeling, reducing the risk for sea sickness.

The overall feeling was of being in a high quality hotel. And that’s not too much considering that the offshore technicians will work in ‘2 weeks on – 2 weeks off’ shifts, with the ESVAGT crew even staying longer, 4 weeks. The crew changes are done by crew transfer vessels (CTVs).

Accessing the turbines

There are several options to transfer the Siemens technicians from the SOV to the wind turbines. An A-type Ampelmann motion compensated gangway provides direct access to a turbine from the vessel and is a good solution in case several technicians need to access a single turbine. During our stay on board it was demonstrated how the Ampelmann works and we could experience the stable platform it creates. The system allows access in wave heights up to 2.5 meters, which is significant versus the 1.5 meters allowed in conventional CTVs.

An ESVAGT in-house newly designed STB, Safe Transfer Boat, can bring up to 12 technicians to the turbines by sea. The Volvo Penta IPS system does give the STB 12 similar positioning capabilities as a conventional DP system. The STB can reach speeds of around 30 knots and still operate in significant wave heights of 1.5 metres. ESVAGT is the only company to operate this vessel. The crew require one year of training to be able to work with the STB. An additional, smaller vessel, the STB 7, is also available for accessing the turbines. Depending on the intensity of the maintenance activities these options can be used simultaneously. For example, during intensive maintenance work activities the SOV can access up to five turbines within 2.5 hours to safely transfer technicians via the Ampelmann.

ESVAGT Froude’s sister vessel the ESVAGT Faraday (named after Michael Faraday, a British physicist and chemist who was working on electro magnetism and also the name giver for CS Faraday, a cable ship built 150 years ago for the Siemens brothers) was officially christened two days later in Hamburg and will be servicing the Butendiek wind farm, owned by wpd Offshore.

Siemens also placed an order for two more Service Operation Vessels with Bernhard Schulte and their affiliate Windea Offshore. The vessels will be built by Ulstein Verft Norway. They are going to be the first with ULSTEIN SX175 design with X-STERN & X-BOW from Ulstein Design & Solution and will have Uptime International’s walk to work access system and a helideck fitted. The two vessels will become operational in 2016 and 2017 and will be used for servicing the Dutch Gemini as well as the German Sandbank and DanTysk wind farms.

Royal IHC

With several vessels already proving their added value on projects in the O&M phase and sometimes during construction, and others, just launched, that still have to prove themselves, it is time to look at he newest designs that are still fresh on the designer’s CAD programme. There are several companies who have, or are designing, their own SOV design, such as Damen Shipyards’ Damen ASV 9020 Walk to Work Vessel and Acta Marine’s Windfarm Offshore Support vessel Acta Orion. Another company is now Royal IHC.

OW23_single page 21 5Dutch engineering and construction company Royal IHC is already well known for several vessel and equipment designs. Their Hydrohammer®, for example, has been used for monopile installation activities on a large number of the European wind farms. The company has, however, recently also been busy with several offshore wind farm vessel designs. One of which includes a Service Operation Vessel (SOV). Or, better said, two SOVs. Offshore WIND spoke to Stefan Lettink, Sales Manager Renewables, Tim van Opstal, Product Proposal Manager Standardized Offshore Vessels, and Richard Agema, Product Developer Renewables, at Royal IHC at their office in Krimpen aan de IJssel.

Royal IHC spoke to key stakeholders in the offshore wind market to find out what the main needs and criteria were for a new service vessel. The outcome proved that not all the stakeholders had the same criteria in mind for their ideal vessel. Their different preferences were especially clear when it comes to the choice of access to the turbine installation. While in general the stakeholders selected to have an access system on board the vessel, some of them did show preference for the use of CTV’s or RIB’s.

Another factor that was variable concerned the total number of passengers. Mr Lettink explained that this has mainly to do with the summer campaigns. While a smaller vessel would be an efficient solution for operation in wind farm projects throughout the year it would most likely need additional help during the summer campaign when, for example, 9 technicians can be working on a turbine at the same time. A larger vessel, however, would be considerably more expensive outside the summer campaign, when some of the cabins would be empty. They originally started the design for a 60 metre vessel which could carry up to 32 persons including crew.

However the overall preference was for the larger vessel. So while Royal IHC will keep the smaller design and make it available to the market when required, they went back to the drawing board to design a larger vessel. The end result was an 82 metre, DP2 vessel with an 18 metre beam and a 5 metre draft. The design includes accommodation for 60 persons, including crew, for optimal workability. There is 300m2 for storage area, 4 workshops and a main crane will be able to lift 5 tonnes at 20 metres reach.

The accommodation is made up of single cabins with private bathrooms. There are recreational areas including a gym, sauna, cinema, a game room and an enclosed sky lounge area. Although in general most of the technicians are male they have added changing facilities for women. Meeting rooms and offices enable crew, technicians and clients to catch up and discuss day schedules and other topics. Something else is also provided that is an important part of modern life – there is a WiFi network provided on board. Mr van Opstal: “Whendesigning the vessel we focused on life on board. The technicians should notice as little as possible that they are at sea. Comfort and safety are vital here. But the same goes for the products, he adds. There should be a high redundancy in movement of people and goods.”

Mr Lettink explains more in detail how this is processed in the design. For example, the engine room has been sited at the after end of the vessel, reducing the sound and vibrations in the accommodation area and the possibility of fumes or smoke where people are boarding or working out on deck. Two flume and stability tanks are placed in the middle of the vessel to reduce any uncomfortable movement of the vessel which, he adds, is something unique with this type of vessel in the market. There is an elevator for inter-deck movement of cargo pallets, of up to 300kg to enable fast and efficient carriage of goods. An ergonomic design throughout the vessel creates ease of movement for freight or stores when loading and an easy flow for crew and technicians alike from work place to changing rooms – to recreational areas – to accommodation, all of which increases efficiency and safety.

But Mr van Opstals tresses: “Safety and comfort on board a vessel is increasingly important, and at the same time automation is becoming an integral part of every aspect of the vessel and people on-board.” The design team did not just look at the quality of the vessel itself but also at the hardware used to design the vessel. “IHC has in-house knowledge of automation, control systems and DP, which gives the opportunity to integrate systems in an early phase of design. By working together with all the relevant departments within Royal IHC we can offer every client a personal integrated approach.”

The design team is now in the final phase of the SOV designs. Keep an eye on our news site www.offshorewind. biz for future announcements. As mentioned, Royal IHC is also busy with other vessels for the offshore wind industry. Read more in the WTIV article in the next edition of Offshore WIND in October!

Sabine Lankhorst