 Hubbard was assigned to Lawley & Son Shipyard, in the Neponset area of Boston, Massachusetts in connection with the conversion of the "YP-422" from 25 June to 28 July 1942 when she was placed in commission with Hubbard in command.Hubbard was relieved of his command on 1 October 1942, a few weeks after "YP-422" underwent a 27-hour training exercise in August 1942.A dispatch sent by the Commandant of the Boston Navy Yard on 25 September 1942 described Hubbard as "not temperamentally fitted for independent command".