Ships provide hangers but I always bring extra hangers so I can keep my outfits matched together. I like to bring the ones that do double duty so that you can hang pants and a top on the same one, if you overpack like I do, you will have enough space in the closet.
If you are lucky and are able to pack that day of cruising you can just pack everything on your own hangers and when you get on the ship you just hang everything up and put the ships hangers in the laundry bag, just remember to put them back otherwise they may charge you for them.