We would like to go from Chongqing to Yichang by passenger ship in the middle of February.

Oh, the cruises are actually available throughout the year. The only difference is that there are much less in winter, including mid Feb. So you still have a chance to experience it. I suggest you turn to an agent to book the tickets in advance. If needed, Travel China Guide can be a good choice. Their contact is traveltravelchinaguide.com for your reference.