Complex design challenges
The vessel has been designed to carry components and fuel for Ariane rockets from France to French Guiana, has an overall length of 121 meters, a beam of 22 meters, a design draft of 4.3 meters and a design speed of 16.5 knots. The ship replaces two 115 x 20 m vessels now performing the same tasks and, partly because of this, must meet a multitude of sometimes conflicting requirements within very limited main dimensions, leading to a complex design challenge. Because the vessel must navigate up a river in French Guiana, the maximum draft there is only 3.8 meters. The light, bulky cargo to be carried also requires a lot of deck area within limited main dimensions. This results in a bulky, wide, shallow vessel. However, the cargo requires low acceleration while the intended sailing schedule requires high speed.
To achieve the target speed in an efficient manner, a unique hull shape was developed and the vessel is equipped with auxiliary propulsion by means of four Oceanwings wingsails, which, based on a sailing schedule of one roundtrip per month during the crossing, should yield fuel savings of about 18%. It is a twin-screw vessel with a praam-shaped stern. Instead of traditional shaft lines with outriggers, a hull shape with two nacelles was chosen. These are asymmetrical and therefore improve the wake field, provide course stability when sailing, increase deplacement and provide space for the placement of the propulsion train which benefits the length of the bilge.