As always, it would be comforting to hear from a guinea pig who's actually done it, but Shanghai PSB says ship-to-airport transit without visa is doable under the 24-hour policy (not the 72-hour policy) if documents are in order: "It's unnecessary for aliens on board cruise ships to worry about not being allowed to enter China without holding Chinese visas. Aliens who meet all the requirements of the related articles can transit without visas after submitting the applications."

http://www.sh-immigration.gov.cn/lis...?lx=37&id=2943