I can't seem to build a galley in my city of Zunzhong, the western most city for the Zhao. I'm new this this scenario, so I may be missing something, but I have Sailing, and I can't see anything in the civlopedia about galleys having any other requirements. The scenario talks about the need to utilize rivers to seige cities with galleys, and yet I can't build it!? The city clearly has navigitable waterways adjacent to it, as I have built a lighthouse.

Any ideas? Thanks!

it's a known bug.