A model for second-harmonic resonance between two gravity–capillary waves is derived, for the case where weak wind and laminar viscosity are of comparable importance. It is revealed that there exist two threshold wind speeds. For winds weaker than the lower threshold, waves are damped. For winds stronger than the upper threshold, the wave energy becomes unbounded and the spectrum cannot be confined to two resonating harmonics. In the intermediate range there exist steady progressive combination waves of the first and second harmonics. These are Wilton's ripples in equilibrium with wind input and viscous dissipation, and are probably physically observable.