The ULSTEIN X-BOW®, the inverted bow concept, redefined marine engineering. The bow concept was launched in 2005, together with the first shipbuilding contract, and gained immediate interest from shipowners. The X-BOW hull line design has been tried in most weather conditions.
The X-BOW® - explained by our chief designer, Øyvind Gjerde Kamsvåg
Developing the maritime experience
The X-BOW (and later, the X-STERN) is one of ULSTEIN's main contributions to maritime history. X-BOW vessels are being built at shipyards on many continents. Currently, more than 100 vessels with this bow concept are being constructed or are sailing around the world.
How does the X-BOW® work?
The X-BOW introduces the gentle displacer; a tapered fore ship shape with a different volume distribution as well as sectional angles, resulting in a wave piercing effect at small wave heights, and also reduces pitching and bow impact loads in bigger seas. When comparing fore ship volumes with more conventional, bulbous bow shapes, the X-BOW has more displacement volume starting from the waterline.
The experience is quite amazing. I cannot imagine myself ever travelling with a conventional bow vessel again in winter time. Captain of the AHTS 'Bourbon Orca'
Instead of just rising on the waves and then dropping with colossal force, the X-BOW® is able to distribute the force more evenly across its surface – enabling the ship to remain more stable during poor weather conditions, increasing comfort for passengers and crew alike. And because it uses less fuel to get through the waves, it also helps to save energy.
In her right element when head seas get rough
The X-BOW vessel is in her right element when in the more harsh environments. In rough head seas, the slamming will be reduced, resulting in reduced vibrations. This is not only a question of comfort, but also the security for those travelling on the vessel. This is where the X-BOW design excels. And this becomes stories, remembered and told by the crew and passengers on these vessels.
'It’s a totally different experience! You don’t feel the sea. In big seas, I kept waiting for the slamming, but it never came. Other ships can only keep half the speed.' Captain of the expedition cruise vessel 'Greg Mortimer'
From a Health, Safety & Environment (HSE) point of view, reduced accelerations and slamming forces mean less wear and tear on people and equipment. The X-BOW has very little spray, so the deck will more easily remain dry behind. It takes very little water on deck to start being a hazard, or simply a nuisance.
- Improved power efficiency
- Soft entry in waves
- Very low levels of noise and vibrations
- Reduced bow impact and slamming
- Reduced wave-induced vibrations
- Improved resting time
- Lower acceleration levels
- Lower pitch response due to volume
- More comfortable on board conditions
- Lower speed loss
- Reduced spray
Statements from X-BOW® users
With feedback like ‘amazing experience’ and’ 'I’ll never again work on any other type of vessel in winter’ being stated by crews on X-BOW® vessels, it is hard to ignore the impact this hull innovation has had since it first appeared in 2005.Real life stories
The X-BOW® experience
The X-BOW® makes a huge difference in sea behaviour. It splits the wave energy and reduces the slamming impact. Successfully proven in more than 100 ships, the hull shape has recently become a game changer for expedition cruising. Yachts will be next.Jump into the adventure!
Improved power efficiency
Safety & less damage
X-BOW® - how it started
When times are tough, it is still possible to nurture and grow good ideas. That’s the story behind the ULSTEIN X-BOW® hull line design, which upon its introduction in 2005 literally turned the image of the ship’s bow upside down.The development of the X-BOW
When presenting the X-BOW® design in 2005, the designers claimed that these vessels would be easier and less resource intensive to build. In 2006, this statement was tested in reality through the construction of an X-BOW® hull at Maritim Ltd: "It was easier to build the backward-sloping bow than a conventional bow."Simplified shipbuilding
The X-BOW® inspires artists
The X-BOW has inspired various artists, from bank note and stamp illustrators, to church architects and animators.The X-BOW inspires
Surfing on top of the waves
The X-BOW® is somewhat the reverse of a conventional bow, leaning backwards instead of forwards. An X-BOW vessel cleaves the waves, significantly reducing noise and vibration. She can sail faster and consume less fuel in high waves than a conventional bow would allow. And she is more comfortable for the crew.Organic lines
TANK TEST AND REAL-LIFE COMPARISON
When new hull designs are undergoing tank tests, a scale model must endure various waves and wave length conditions. We have performed model tests and comparative model tests for X-BOW hulls and bulbous bows in areas such as supply, seismic, offshore construction, drill, short-sea and anchor handling tug supply.TANK TESTING