Hybrid boat comprising: - an internal combustion engine; - a reversing device to allow at least one condition of forward movement and one of reverse movement of the boat; - a propeller or impeller; - transmission means (X1, TB, X2) comprising: + a transfer box having a first inlet, a second inlet and a single outlet, + an input shaft, and + an output shaft interposed between said single outlet and said propeller or impeller; and - an electric motor operatively connected with said second inlet; wherein said transfer box comprises means (DC1, DC2) for selectively connecting said internal combustion engine and/or said electric motor with said single outlet, which allows to select the connection of the electric motor or the internal combustion engine or both the electric motor and the internal combustion engine, to said propeller or impeller; wherein said transfer box comprises a first and a second transmission shafts (A1, A2) parallel to each other; characterized in that - the internal combustion engine is provided with said reversing device, so that the transmission means are connected between said reversing device and said propeller or impeller, and said input shaft is interposed between said reversing device and said first inlet; said first transmission shaft is formed in two parts (A11, A12), wherein a first part of the two parts defines said first inlet and a second part of the two parts defines said single outlet, and wherein said first and second parts are reversibly connectable to each other by means of a first dog clutch; the first transmission shaft having a first end defining said first inlet and a second end, opposite the first end, defining said single outlet; wherein a first toothed wheel is fitted on said second part; the first toothed wheel being reversibly connectable to said second part by means of a second dog clutch; and wherein said second transmission shaft comprises a second toothed wheel that operatively connects with said first toothed wheel. - an internal combustion engine; - a reversing device to allow at least one condition of forward movement and one of reverse movement of the boat; - a propeller or impeller; - transmission means (X1, TB, X2) comprising: + a transfer box having a first inlet, a second inlet and a single outlet, + an input shaft, and + an output shaft interposed between said single outlet and said propeller or impeller; and + a transfer box having a first inlet, a second inlet and a single outlet, + an input shaft, and + an output shaft interposed between said single outlet and said propeller or impeller; and - an electric motor operatively connected with said second inlet; wherein said transfer box comprises means (DC1, DC2) for selectively connecting said internal combustion engine and/or said electric motor with said single outlet, which allows to select the connection of the electric motor or the internal combustion engine or both the electric motor and the internal combustion engine, to said propeller or impeller; wherein said transfer box comprises a first and a second transmission shafts (A1, A2) parallel to each other; characterized in that - the internal combustion engine is provided with said reversing device, so that the transmission means are connected between said reversing device and said propeller or impeller, and said input shaft is interposed between said reversing device and said first inlet; said first transmission shaft is formed in two parts (A11, A12), wherein a first part of the two parts defines said first inlet and a second part of the two parts defines said single outlet, and wherein said first and second parts are reversibly connectable to each other by means of a first dog clutch; - the internal combustion engine is provided with said reversing device, so that the transmission means are connected between said reversing device and said propeller or impeller, and said input shaft is interposed between said reversing device and said first inlet; said first transmission shaft is formed in two parts (A11, A12), wherein a first part of the two parts defines said first inlet and a second part of the two parts defines said single outlet, and wherein said first and second parts are reversibly connectable to each other by means of a first dog clutch; the first transmission shaft having a first end defining said first inlet and a second end, opposite the first end, defining said single outlet; wherein a first toothed wheel is fitted on said second part; the first toothed wheel being reversibly connectable to said second part by means of a second dog clutch; and wherein said second transmission shaft comprises a second toothed wheel that operatively connects with said first toothed wheel.