A marine propeller combination for a marine propulsion unit includes a first propeller and a second propeller arranged to rotate simultaneously in opposite directions about a common rotational axis. The marine propeller combination is configured such that the first and second propellers are angularly positioned such that during one revolution one of the blades of the first propeller is aligned with a drive leg of the marine propulsion unit when a blade gap of the second propeller is aligned with the drive leg, or one of the blades of the first propeller is aligned with the drive leg when one of the blades of the second propeller is aligned with the drive leg. The disclosure further relates to a marine vessel and to a method of operating a marine propeller combination.

A survival craft for maritime evacuation of passengers and crew members from a vessel or an offshore facility is disclosed. The survival craft has a hull, predominantly made of non-rigid inflatable tubes and one or more shells, the hull has a length, a width and a centerline, a bow and a stern. The survival craft further comprises a first pair of engine-powered propulsion means arranged at the stern on opposite sides of the centerline, and a second pair of engine-powered propulsion means arranged at the bow on opposite sides of the centerline, each engine-powered propulsion means has a propeller or a water jet, wherein a horizontal angle of each propeller or water jet of each engine-powered propulsion means can be independently set in relation to the centerline.

A survival craft for maritime evacuation of passengers and crew members from a vessel or an offshore facility is disclosed. The survival craft has a hull, predominantly made of non-rigid inflatable tubes and one or more shells, the hull has a length, a width and a centerline, a bow and a stern. The survival craft further comprises a first pair of engine-powered propulsion means arranged at the stern on opposite sides of the centerline, and a second pair of engine-powered propulsion means arranged at the bow on opposite sides of the centerline, each engine-powered propulsion means has a propeller or a water jet, wherein a horizontal angle of each propeller or water jet of each engine-powered propulsion means can be independently set in relation to the centerline.

An intentional fluid manipulation apparatus (IFMA) assembly with a first thrust apparatus that imparts a first induced velocity to a local free stream flow during a nominal operation requirement. The first thrust apparatus creates a streamtube. A second thrust apparatus is located in a downstream portion of the streamtube. The second thrust apparatus imparts a second induced velocity to the local free stream flow. The second induced velocity at the location of the second thrust apparatus has a component in a direction opposite to the direction of the first induced velocity at the location of the second thrust apparatus.