you have a few options. If the ship does not have a self-service laundry they might have a laundry service - not just dry cleaning, check your daily cruise newsletter when onboard for laundry specials they sometimes run a flat-rate special for an entire bundle of laundry that is inexpensive. You could wash out your delicates in the sink in the bathroom and then hang them in the shower. Socks are another matter, i would pack enough for the entire trip( put them in a Ziploc type bag and squish all the air out of the bag) takes up a lot less space this way. Last option - YUCK find a laundromat at one of the ports midway thru your cruise and do a load or two.