This is not a question so much, of how to procure alcohol for a ship in port, as much as it is a question of the applicable Naval regualtion and general orders concerning the prohibition of the consumption of alcohol by ship's personnel aboard ship and the exception to that when the ship has been at sea for 45 consecutive days.

You might conceivably be able to purchase said alcohol in the same manner as if you had been at sea for 45 consecutive days if, 1) The Naval regulation or general order prohibiting it has been temporarily suspended, 2) the VCNO or the Dir., Navy Staff has authorized the possession and consumption of alcohol aboard vessels IAW CNO OPNAVINST 1700.16B and VCNO ltr 5402 Ser N09D/1U11824, 6 Dec 2011, and 3) the contracting officer or the ships Purser processed the requirement.