how often do the auto ferry's depart from orient point

Usually every hour, but there are different boats. Some are passenger boats only, and some might have better accommodations for your family (i.e. eating area). You can go through the booking process for the day you want and see each boat and times they depart for the day you choose.

Every hour

Every hour . Some are just for passengers. Some also only can take cars.

Every hour on most days in spring and summer.

Usually every hour