Yep. If you've got any non-US passports holders, or don't have a green card, entry into the US on a private boat (includes charters) means they need visas even if the US has visa agreements with that country - that agreement only applies to common carriers like airlines and passenger vessels (like ferries and cruise ships).
Standard process is to check out of BVI, check in to USVI, check back into BVI. You don't want to do the USVI checkout, not required when leaving the US and the BVI is used to those returning on charters. Make sure you have a believable idea of the vessel weight, it's not always on your vessel papers.
.
