27 C.F.R. § 31.93
Persons may carry on the business of a retail dealer in liquor or of a retail dealer in beer on supply boats or vessels operated by them when those persons operate from a fixed address in a port or harbor and supply exclusively boats or other vessels, or persons thereon, at that port or harbor. Such persons must specify, on an attachment to the registration form, the following: that the business will consist of supplying exclusively boats, vessels, or persons thereon; the name of the port or harbor at which the business is to be carried on; and the fixed address from which operations are to be conducted. When such sales are to be made from two or more supply boats or vessels, the dealer must also specify on the attachment the number of supply boats or vessels for which registration is being made. If the dealer operates from two or more fixed addresses, the dealer must prepare one registration form covering all of those addresses and must include on the attachment to the registration form the number of supply boats or vessels operating from each address.
27 C.F.R. § 31.93