as a jap and jacd princess provide you with your uniforms!!
jacd's tend to need a few formal outfits (dresses/suits) as you get to mingle in passenger areas on formal nights etc when you are not working!! you also get to go to the ships disco in your own clothes, whereas other departments have to wear their awful formal uniform!! ( I suffered this experience being a shoppie)
i was told not to take much of my own stuff as i would be living inmy uniform, but luckily i didnt listen and took 2 suitcases of my own clothes! if you are planning on socialising in the crew bar etc you will need whatever you feel comfortable in!!
enjoy your contract!!