X-Bow: 10 Years of a Revolutionary Design

In 2005, BOURBON becomes the 1^st offshore operator to adopt an inverted bow vessel, the Bourbon Orca. A look at this innovative design, dubbed the X-BOW®.

In 2006, the Bourbon Orca joined the BOURBON fleet, the very first inverted-bow AHTS designed by the Norwegian ship designer ULSTEIN. The main feature of this vessel: a slender hull water line and a smoother volume distribution in the foreship, particularly suited to the navigational conditions in the North Sea. The payoff: better handling and reduced pitching in rough seas. "While a traditional bow vessel rises on the waves and then drops violently onto the surface of the water, an X-BOW® vessel, less subject to the vertical motions induced by the waves, continues on course more smoothly, while maintaining its speed. And because it uses less fuel to get through the waves, it also helps to save energy," says Tore Ulstein, Deputy CEO and Chief Market & Innovation Officer in Ulstein Group.

So we can understand why this type of vessel also offers more comfortable working conditions for the crew. "Less shaking, it also means less vibration, less noise and less splashing,"says Arnkjell Brandal, who was the first officer to command the vessel, until May, 2015. This seafarer, used to traditional bows tells us of his first impressions on board. "It was like a shock, paradoxically. This vessel was nothing like what I had experienced before! But I soon felt the difference, especially in traction situations: fluidity, strength and stability!"

Propelled by BOURBON

The Bourbon X-BOW® story starts in 2004, when ULSTEIN was working with BOURBON and several industry players on a project to improve the safety of anchor handling operations. "Trond Myklebust, who at the time was Marketing Director of Bourbon Offshore Norway, challenged us: to rethink the design of parts of the vessel, including the bow," explains Tore Ulstein. For the Norwegian designer and shipbuilder, all the ingredients required to design tomorrow's offshore vessel were assembled: the encouragement of a customer who is a leader in its market, a constant search for innovation, and a strong partnership with leading players. "BOURBON asked us to dare... and together we did it!"

The advantages of the X-BOW® design were revealed late in 2004 and the start of 2005, when tested in a towing tank. As Tore Ulstein explains: "We conducted these tests with scale models, but in real situations, with waves from different directions to analyze the vessel's behavior. The very positive results encouraged us in this direction." In April 2005, BOURBON would go on to acquire its first X-BOW® vessel!

One innovation includes others

If the X-BOW® design remains the flagship innovation of the Bourbon Orca, this vessel is also equipped with a new anchor-handling system and diesel-electric propulsion. "With very good energy efficiency, it is also equipped with azimuth thrusters which allow it to rotate 360° for quick direction changes," says Arnkjell Branda, former captain of the Bourbon Orca.