Rates are set by fiscal year, effective October 1 each year. Find current rates in the continental United States ("CONUS Rates").
Travel by cruise ship on a business trip is deductible.
Your maximum deduction is $5,124 (2 x $366 x 7). The double per diem rule applies without regard to the 50% limit on meal costs if meals are not separately stated in your bill.
If meals are included in your bill but not listed as a separate item, then you may apply the double per diem rate to the total amount of the bill. If meals are separately stated on your bill, such amount must be reduced by 50%; the 100% limit does not apply to meals on luxury vessels.