Propulsion system of marine vessel

A marine vessel having a longitudinal direction and a stern area and comprising:

• a hull which is provided with at least one skeg,
• a first propulsion device in the stern area of the vessel for providing propulsion power, the first propulsion device including two shaft-driven propellers located to opposite respective sides of a center line of the hull and spaced from the skeg transversely of the hull, and
• a second propulsion device aft of the skeg for imparting thrust to the hull, the second propulsion device being turnable relative co the hull between a first position in which the second propulsion device imparts thrust in the longitudinal direction of the vessel and a second position in which the second propulsion device imparts thrust transverse to the longitudinal direction of the vessel,
• and wherein the second propulsion device has a forward extension which minimizes a gap between the second propulsion device and the skeg when the second propulsion device is in the first position and forms an opening between the second propulsion device and the skeg for water to flow through when the second propulsion device is in the second position,
• the forward extension of the second propulsion device and the skeg have substantially parallel counter surfaces mating with each other when the second propulsion device is in the first position,
• and the skeg has an aft surface forward of the second propulsion device, said aft surface being arcuate and having a radius substantially equal to the distance between the aft surface of the skeg and the turning axis of the second propulsion device.