How much does it cost and how long does it take for a ferry from HKIA to Guangzhou ? should i pre book

The ferry service to GZ is only available on Tuesdays, Thursdays and Saturdays and only one ferry operates at 16:00.
The ticket fare varies from 304HK$ to 356HK$ for adult for ecomony class and 402 to 471HK$ for super class. It is suggested to prebook on Turbojet and you can find more detail information on that website.
The journey takes around an hour to reach GZ.