[QUOTE=Traitor Yankee;144753]Over 100 tons if you want a 1600 mate, if most of your time is under 100 you will get a 500 mate.[/QUOTE]
Obviously, take any job you can find that will give you experience. That said, try to avoid working as a deckhand on vessels under 100 tons. Look for jobs as AB on vessels over 200 tons. While it might be worthwhile to take a job as an OS to get on with the right company, or on the right boat, especially if it is over 1600 GRT , if your goal is to move up, you are much better off sailing as an AB.