Behind the Viking ship on the 100-krone banknote, the contours of a ship with an X-BOW® can be seen.

The X-BOW® is a bow concept developed by the Sunnmøre-based company Ulstein Design & Solutions AS. The bow is inverted abaft so that the ship is longest at the waterline. In principle, a hull constructed with this design will have greater displacement volume starting from the waterline than conventional hulls.

X-BOW® was launched in 2005. That same year, the bow concept received the Norwegian TechAward and was first used on a ship in May 2006.

The greater displacement volume of X-BOW® hulls makes them better able to handle oncoming waves than conventional hulls. The bow floats over the oncoming waves that a conventional bow would need to pierce through. This reduces accelerations and provides smoother sailing for crewmembers. At the same time, the reduction in drag reduces fuel consumption.

The X-STERN™-design is a continuation of X-BOW®. X-STERN™ applies the same principles to the aft ship, and enables the ships to hold their position by placing their stern towards the weather.