Hybrid marine drive unit (103; 203; 303; 403) configured to be mounted to a transom (102; 202; 302; 402) of a marine vessel, which drive unit (103; 203; 303; 403) comprises - a drive housing (104; 204; 304; 404) configured to be rigidly mounted on the transom (102; 202; 302; 402), - a propelling unit (105; 205) rotatable about a vertical axis and mounted to a lower surface (106; 206; 306; 406) of the drive housing (104; 204; 304; 404), wherein the propelling unit (105; 205) is arranged to be rotatable relative to the lower surface (106; 206; 306; 406) of the drive housing (104; 204; 304; 404) by a steering arrangement (240; 340; 440) in order to steer the vessel, and - a transmission with at least a vertical drive shaft (210; 310; 410) located in the drive housing (104; 204; 304; 404) and extending into the propelling unit (105; 205; 305; 405), which vertical drive shaft is arranged to transmit drive torque from at least one of multiple sources of drive torque (111, 121; 211, 221; 311, 321; 411, 417, 421), wherein: - the drive unit (103; 203; 303; 403) is an azimuthing pod drive removably attached to the transom (102; 202; 302; 402) - the vertical drive shaft (210; 310; 410) is operably connected to at least one first source of drive torque (111; 211; 311; 411, 417) arranged within the drive housing (104; 204; 304; 404), and that - the vertical drive shaft (210; 310; 410) is operably connected to a horizontal output shaft (220; 320; 420) extending into the drive housing (104; 204; 304; 404), wherein the horizontal output shaft (220; 320; 420) is configured to extend through the transom (102; 202; 302; 402) when the hybrid marine drive unit (103; 203; 303; 403) is mounted to the transom (102; 202; 302; 402) of the marine vessel, wherein the horizontal output shaft (220; 320; 420) is connectable to a second source of drive torque (121; 221; 321; 421) located within a hull of the vessel. - a drive housing (104; 204; 304; 404) configured to be rigidly mounted on the transom (102; 202; 302; 402), - a propelling unit (105; 205) rotatable about a vertical axis and mounted to a lower surface (106; 206; 306; 406) of the drive housing (104; 204; 304; 404), wherein the propelling unit (105; 205) is arranged to be rotatable relative to the lower surface (106; 206; 306; 406) of the drive housing (104; 204; 304; 404) by a steering arrangement (240; 340; 440) in order to steer the vessel, and - a transmission with at least a vertical drive shaft (210; 310; 410) located in the drive housing (104; 204; 304; 404) and extending into the propelling unit (105; 205; 305; 405), which vertical drive shaft is arranged to transmit drive torque from at least one of multiple sources of drive torque (111, 121; 211, 221; 311, 321; 411, 417, 421), - the drive unit (103; 203; 303; 403) is an azimuthing pod drive removably attached to the transom (102; 202; 302; 402) - the vertical drive shaft (210; 310; 410) is operably connected to at least one first source of drive torque (111; 211; 311; 411, 417) arranged within the drive housing (104; 204; 304; 404), and that - the vertical drive shaft (210; 310; 410) is operably connected to a horizontal output shaft (220; 320; 420) extending into the drive housing (104; 204; 304; 404), wherein the horizontal output shaft (220; 320; 420) is configured to extend through the transom (102; 202; 302; 402) when the hybrid marine drive unit (103; 203; 303; 403) is mounted to the transom (102; 202; 302; 402) of the marine vessel, wherein the horizontal output shaft (220; 320; 420) is connectable to a second source of drive torque (121; 221; 321; 421) located within a hull of the vessel.