A marine vessel having a bow, a stern, a center of rotation, a mounting assembly, a pair of stern-mounted propulsion units (32, 34) and a longitudinal centerline which extends from the stern to the bow and which is situated between the sides (18, 20) of the vessel, the propulsion units (32, 34) each comprising an engine (32, 34) having a propeller (100, 104) with a propeller axis (36, 38), which corresponds to the line of action (102, 106) of its propulsion force, and a total steering range, the mounting assembly comprising a pair of angle-setting members (48, 52) and a pair of stern brackets (42, 44), each propulsion unit (32, 34) being mounted to the stern by a respective stern bracket (42, 44) and one of the angle-setting members (48, 52) is connected to each stern bracket (42, 44) to forwardly angle the propulsion units (32, 34) towards the bow of the marine vessel when each propulsion unit (32, 34) is at the center of its total steering range, wherein the angle-setting members (48, 52) angle the propulsion units (32, 34) inwardly and forwardly in the range of greater than 0 degrees and less than 30 degrees relative to a longitudinal axis of the marine vessel and the propulsion units (32, 34) are arranged to: achieve sideways movement by steering the propeller axes (36, 38) of the engines (32, 34) such that they intersect at a point of intersection which is aligned with the center of rotation and moving the propeller of a first one of the engines forward to provide a line of action with a forward propulsion force whilst moving the propeller of a second one of the engines rearward to provide a line of action with a rearward propulsion force equal to the forward propulsion force; and allow heading corrections during sideways movement by steering the propeller axes (36, 38) of the engines (32, 34) fully toward each other, such that they intersect at a point of intersection along the centerline and rearward of the center of rotation, and by steering the propeller axes (36, 38) of the engines (32, 34) toward each other so that they intersect at a point of intersection along the centerline and forward of the center of rotation, thereby to allow the vessel to have both clockwise rotational adjustment and counter-clockwise rotational adjustment while moving sideways. achieve sideways movement by steering the propeller axes (36, 38) of the engines (32, 34) such that they intersect at a point of intersection which is aligned with the center of rotation and moving the propeller of a first one of the engines forward to provide a line of action with a forward propulsion force whilst moving the propeller of a second one of the engines rearward to provide a line of action with a rearward propulsion force equal to the forward propulsion force; and allow heading corrections during sideways movement by steering the propeller axes (36, 38) of the engines (32, 34) fully toward each other, such that they intersect at a point of intersection along the centerline and rearward of the center of rotation, and by steering the propeller axes (36, 38) of the engines (32, 34) toward each other so that they intersect at a point of intersection along the centerline and forward of the center of rotation, thereby to allow the vessel to have both clockwise rotational adjustment and counter-clockwise rotational adjustment while moving sideways.