Abstract: A marine drive unit for a boat includes a cooling compartment arranged in a drive unit body. The cooling compartment forms part of a closed cooling circuit, where the cooling circuit is arranged to cool propulsion components of the boat, where the cooling compartment comprises an inlet opening, an inlet channel, a lower end, an outlet channel and an outlet opening, where the inlet channel forms a first flow path for a cooling fluid from the inlet opening to the lower end of the cooling compartment. The outlet channel forms a second flow path for the cooling fluid from the lower end of the cooling compartment to the outlet opening, thereby allowing heat from the cooling fluid to dissipate through the outer wall of the drive unit.