Whenever any merchandise remains on board any vessel or vehicle from a foreign port more than twenty-five days after the date on which report of said vessel or vehicle was made, the appropriate customs officer may take possession of such merchandise and cause the same to be unladen at the expense and risk of the owners thereof, or may place one or more inspectors or other customs officers on board of said vessel or vehicle to protect the revenue. The compensation and expenses of any such inspector or customs officer for subsistence while on board of such vessel or vehicle shall be reimbursed to the Government by the owner or master of such vessel or vehicle.