A winch for a sailboat comprising: a support for mounting the winch with respect to a sailboat; a winch drum rotatable with respect to the support; a ring gear fixed with respect to the winch drum; a main drive gear meshing with the ring gear for driving rotation of the winch drum; a manual drive spindle; and a motor gear shaft, wherein the winch is capable of manual operation for forward winding of the winch drum in a first gearing ratio and in a second gearing ratio, the first and second gearing ratios being selected depending on the direction of rotation of the manual drive spindle, the winch further comprising: a first gear train providing the first gearing ratio, the first gear train having a first unidirectional drive means (G2, G4) operable to drive the main drive gear when the first unidirectional drive means is rotated in a forward direction and operable to freewheel when the first unidirectional drive means is rotated in a reverse direction; and a second gear train providing the second gearing ratio, the second gear train having a second unidirectional drive means (G1, G3) operable to drive the main drive gear when the second unidirectional drive means is rotated in a reverse direction and operable to freewheel when the second unidirectional drive means is rotated in a forwards direction, characterized in that the winch further comprises: a third unidirectional drive means (G1, 114) linked to the motor gear shaft, wherein the winch is capable of motorised operation in which the winch drum is operatively linked to the motor gear shaft via the third unidirectional drive means and via at least part of the first or second gear train, and rotation of the third unidirectional drive means by the motor gear shaft in one direction drives the main drive gear and causes forward winding of the winch drum and rotation of the unidirectional drive means by the motor gear shaft in the opposite direction allows reverse winding of the winch drum, wherein the manual drive spindle is provided with a spindle gearwheel which engages with gear wheels (G3, G4) of the first and second drive trains simultaneously during manual operation of the winch, reverse winding torque on the winch drum urging the first and second unidirectional drive means so that the spindle gear wheel locks relative rotation of said gear wheels of the first and second drive trains, and thus prevents reverse winding of the winch drum, wherein the spindle gear wheel is moveable into and out of engagement with at least one of said gear wheels of the first and second drive trains to allow reverse winding of the winch, and wherein the spindle gear wheel is moveable axially along the principal axis of the manual drive spindle. a support for mounting the winch with respect to a sailboat; a winch drum rotatable with respect to the support; a ring gear fixed with respect to the winch drum; a main drive gear meshing with the ring gear for driving rotation of the winch drum; a manual drive spindle; and a motor gear shaft, a first gear train providing the first gearing ratio, the first gear train having a first unidirectional drive means (G2, G4) operable to drive the main drive gear when the first unidirectional drive means is rotated in a forward direction and operable to freewheel when the first unidirectional drive means is rotated in a reverse direction; and a second gear train providing the second gearing ratio, the second gear train having a second unidirectional drive means (G1, G3) operable to drive the main drive gear when the second unidirectional drive means is rotated in a reverse direction and operable to freewheel when the second unidirectional drive means is rotated in a forwards direction, a third unidirectional drive means (G1, 114) linked to the motor gear shaft, wherein the winch is capable of motorised operation in which the winch drum is operatively linked to the motor gear shaft via the third unidirectional drive means and via at least part of the first or second gear train, and rotation of the third unidirectional drive means by the motor gear shaft in one direction drives the main drive gear and causes forward winding of the winch drum and rotation of the unidirectional drive means by the motor gear shaft in the opposite direction allows reverse winding of the winch drum,