An outboard propulsion system for vessels includes a supporting structure (4) to be anchored to the transom wall (5) of the vessel and a plurality of propellers (3) carried by the supporting structure (4). Each propeller (3) is associated to an electric motor (6) with a toroid geometry, having an annular rotor (R) rotatable within an annular stator (S) and defining therewithin a central aperture (A), with the blades (3A) of the propeller (3) which are carried by the rotor (R) and extend to the central aperture (A).

The propulsion unit including a casing having an inner curved surface and an outer curved surface, at least one tire disposed within the casing within a duct defined by the inner curved surface and the outer curved surface, a first propeller and a second propeller having a plurality of blades extending from within the casing toward a center axis of the casing, and one or more motors housed within the casing, the one or motor being configured to operate the at least one tire, the first propeller, and the second propeller independently of one another. There is also provided a vehicle with one or more propulsion units of the present disclosure.