Since its introduction five years ago, the ULSTEIN X-BOW® concept has proven its added value to customers when it comes to enhanced performances in operations, fuel economy, comfort and safety.

However, innovation is a continuous process within ULSTEIN, finding new combinations of potential markets, products and services that allow customers to expand their positions. “Innovation is at the heart of everything we do. Combining environmental friendliness with operational benefits is the challenge”, states Tore Ulstein, deputy CEO at ULSTEIN.

“Our slogan is ’Turning visions into reality’. This phrase sums up what ULSTEIN is all about. We aim to be a global innovation leader in marine operations, dedicated to meet future market challenges. We put tremendous effort into developing sustainably efficient solutions which enhance the value creation of our customers and help to meet future demand in the best possible way”, says Ulstein.

Ulstein points out that the company’s innovative touch is far from new. “ULSTEIN´s shipbuilding activities encompass nearly 100 years of continuous work. Expertise from shipbuilding was important when our design activities started in the 1960s, and several innovations that increased the vessels´ operability and efficiency, and ensured safer work conditions for the crew, were introduced. In today´s design work, we consider the vessel´s complete life-cycle to find solutions that have the least environmental impacts, at the same time improving its operational profile. Our experiences from the offshore oil & gas industry can contribute to develop new innovations for this industry and introduce technologies into the offshore renewable markets. Ultimately, sustainable efficiency is our philosophy,” says Ulstein.


As Ulstein highlights, the X-BOW® hull line design is one of the company’s most significant contributions to maritime innovations. “The inverted bow concept was launched in 2005, and the market responded quickly and positively. Now, almost 20 such vessels are in operation, with nearly 10 others under construction. Over the years the X-BOW® has proven to do what is was designed for – improving vessel motion behaviour, reducing a vessel’s environmental footprint and greatly increasing the operational window and crew comfort on board,” says Ulstein.

Bob Rietveldt, head of the customized design area at ULSTEIN, continues: “Initially developed for offshore support vessel, new markets are being explored where the X-BOW® can have a significant added value. Recently the XDS 3600 deepwater drillship was introduced to the market, being the largest X-BOW® ever developed up to date. After successful model testing of the drillship design, the X-BOW® proved to be very valuable for large vessels that are mostly operating in stationary conditions. The results even exceeded our expectations and we are convinced that this technology can benefit FPSO designs as well. FPSOs are traditionally based on existing tanker designs with the accommodation at the aft, which are not developed for stationary operations. In harsh weather environments, slamming, green water on deck and poor motion behaviour are regarded as major problems, reducing FPSO operability. Adding an X-BOW® benefits the overall design and operability.”


Developing new sources of renewable energy is becoming ever more important in meeting the imperatives of the world’s energy mix. By its nature, renewable energy does not pollute and the sources are endless. ULSTEIN has developed two concepts for turbine installations for the offshore wind energy market, the Windlifter system and the F2F (Floating to fixed) concept.

As Rietveldt explains: “The Windlifter is a dynamically positioned vessel suitable for single lift offshore wind turbine installations, and unlike jack-up units is not limited by waterdepth. The vessel with an ULSTEIN X-BOW® transports four turbines at the same time and uses a modular, mechanical system to skid the turbines from the vessel onto the foundation. The installation system excels in its simplicity and allows for a considerable reduction in power demand and installation time,” says Rietveldt, adding: “It is an attractive alternative for the current market situation. And as the installation system is modular, it provides the vessel with the flexibility to operate in other markets as well, like e.g. subsea construction or deepsea mining.”

“However, our ultimate vision towards the future of offshore windturbine installation is the F2F concept,an alternative to fixed foundations. F2F targets a significant overall cost reduction related to offshore turbine installation, operation, maintenance, repair and decommissioning. Using proven technologies from the offshore oil & gas industry, the unit is completely constructed and commissioned inshore and then floated out to its location by using a tug. So no dedicated (hence expensive) installation units like the currently used jack-ups are required. Moreover, the impact on the marine environment is minimal as no pile driving is required and when decommissioned, no remains are left on or in the seabed.”

ULSTEIN also offers designs for the offshore wind commissioning and maintenance market. Recently Ulstein signed a letter of intent with SeaEnergy Marine to develop new maintenance service vessels for the offshore wind industry, based on ULSTEIN´s SX128 design. “The X-BOW® allows for much smoother vessel motions. This is an important factor, because when the offshore wind industry moves further from the coastline, service vessels must be more versatile in their operations and offer greater crew comfort. In that way they can stay longer offshore instead of sailing back and forth into port every day, increasing uptime”, says Rietveldt.


As mentioned earlier, life-cycle considerations are fundamental to ULSTEIN and the LNG PAX vessel concept is a good example of this, as Ulstein explains. “This X-BOW® vessel is designed according to ULSTEIN’s energy future philosophy, indicated by the water droplet symbol found on the side of these ships. The vessel is a combination of an LNG (Liquid Natural Gas) carrier and PAX (cargo and passenger transport vessel). As one vessel can perform several different duties otherwise performed by two vessels, the carbon footprint is reduced. The vessel also comes with intelligent lighting systems to reduce energy consumption. Additionally, solar energy can be utilised through the use of solar panels in the wheelhouse roof. Also, there are four high efficiency wingsails, along with in-wing solar panels and LNG tank area ventilation pipes. The hybrid LNG and diesel-mechanic/diesel-electric propulsion system contains a combination of shaft lines and contra-rotating podded propulsors, both with high efficiency propellers. These propellers are thin and made from very strong materials (a combination of steel and FRP – fibre reinforced plastics), with slender propeller blade profiles which produce low propeller/ hull interaction effects.”

The energy management and conservation system onboard the vessel ensures that there is heat and energy recovery throughout the ship. For example, the integrated antennas on the wheelhouse roof result in low wear and tear to reduce maintenance. The bridge is made from alternative eco-friendly materials and heat is recovered from the wheelhouse roof.

“The intuitive vessel operating systems focus on environmental efficient operation profiles. The design also includes low resistance bottom paint, and a majority of the vessel systems are recyclable to minimize environmental footprint,” adds Ulstein.


Gas propulsion has proven particularly popular for vessels used in passenger transport, and lately in offshore support vessels. ULSTEIN has taken another step and introduced LNG propulsion in a new area – the subsea construction segment, as Ulstein explains.

“The ULSTEIN PX119 design platform can be large enough to be work as a subsea construction vessel or as a platform supply vessel. The vessel is prepared for optional engine configurations, such as diesel mechanic, diesel electric, dual fuel, or pure LNG, or combinations of these. This optimal flexibility creates a fuel-efficient vessel, with reduced emissions depending on the operational profile. In LNG mode, there are significant reductions in NOx, some reduction of CO2 and a total elimination of SOx emissions. Increasingly, offshore work will be performed in deep water, and the introduction of LNG propulsion in this area will have a major benefit to the local environment.”


A vessel´s operational profile must always be considered when developing the optimal solution for a sustainable, efficient vessel. Although deliveries might be based on proven technology and rigorous quality standards, the system architecture must be considered as a whole, and the right choices have to be made, according to Ulstein: “There can be positive effects by combining technologies and solutions in new ways, or by developing our own systems, like PMS-systems and other control systems.

“Also, the correct amount and size of equipment for the job is essential to reduce emissions. ULSTEIN is developing a design series for standard ships, such as the platform supply vessel ULSTEIN PX106. By accepting a small speed reduction, ship owner will require a lower investment and lower maintenance costs, but they will also create positive effects for the environment, as the fuel consumption will be reduced significantly.”

The size of vessel also needs to be considered, depending on the job being undertaken. Small vessels, for example, can service oil field installations frequently and efficiently. On the other hand, large and optimised vessels can perform jobs otherwise performed by two or three vessels, which can lead to enormous fuel savings.

ULSTEIN believes that the best innovations in the maritime industry takes place through joint efforts between naval architects, vendors, customers and other experts early in the design phase. “The large and powerful AHTS´s ‘Olympic Zeus’ and ‘Olympic Hera’, design type ULSTEIN A122, are good examples of this,” says Ulstein.

The newly developed hybrid propulsion system (diesel mechanic / diesel electric) in these vessels provides maximum fuel efficiency. Most of the time, including during anchor handling operations, the vessels operate in diesel electric mode, thereby reducing fuel consumption and increasing emission savings.

The vessels require only low or medium power for the majority of their operational time, and the fuel savings are quantifiable, as Olympic Shipping senior vice president, Runar Stave states: “On average, we can run the ship on 70 percent of the fuel of a conventional diesel direct driven anchor handler.”


Considering green issues when it comes to the use of vessels is important from both environmental and commercial perspectives. Green shipping solutions are at the heart of the vessel designs from ULSTEIN. Tore Ulstein says: “As a company we invest heavily in research and development projects and allocate approximately NOK 100 million annually to innovation and new development. We focus on both new types of vessels and solutions that help our customer increase his market value, while reducing emissions and causing less harm to the environment. ULSTEIN also supports professorships and doctoral research programs that have significant potential for further developing the industry. We believe that these and other initiatives will help take the industry forward into a brighter, greener future.”


Source: ulsteingroup, August 24 , 2010;