what is the ferry scheduled time from hong kong airport to zhuhai? we will arrive at 1730 hr.

There are four ferries daily, which depart at 12:15, 14:15, 17:00 and 20:10. You can catch the last one, but you need to wait for some time. Alternatively, at the Coach Terminal of T2 at HKIA, there are direct buses to Zhuhai for you to choose. According to your timng, the best schedule is 18:55, and it shall take you to Gongbei Border in 4h.