The individual Immigration form is the same requirement whether you arrive by ferry, air, charter vessel, or private vessel. CYOA usually has these on your boat so you can take the 5 minutes to fill them out before you head to C&I.

Additionally, if arriving by charter vessel or private vessel (including a BVI charter that goes to USVI and returns to BVI), you have to fill out the 1-page manifest with vessel information and crew list. I know CYOA provides a form with instructions on filling it out.

Immigration Form Tip #1 - fill out and sign the bottom tab of the form. The Final Port will be your next Port of Call after departing BVI (typically Cruz Bay or Charlotte Amalie, USVI) and the departure date.
Tip #2 - best to have each crew member fill out and sign the back of the Form. If you are just bringing in Ship's Stores then indicate NO for importing food and show $0 for value of goods.

Manifest Tip #1 - In the crew birth place column, spell out the "US State name (not the abbreviation), USA" for US born crew members - don't need to list the town.
Tip #2 - list skipper as "Master" and crew as "CREW"
Tip#3 - in the box asking if you've brought in guns and ammo, write "NONE"!