No, ships do not have irons in the cabin. In fact, they are not allowed at all due to fire hazards. On the Carnival ships however, you will find a Laundry room on many decks. There is a iron and board as well as a coin operated washer & dryer available for you to use. Pack your nice things in plastic dry cleaner bags. Pack tight! Movement in suitcases causes wrinkles.
Bon voyage