"
And the cook in scuppers with the staggers and the jags
I've heard versions with Jiggers and Jags. In advanced alcoholism a person might shake in an uncontrolled way. I don't know if this is limited to withdrawal. But the main point the artist is portraying is that this was a ship with some critical problems yet he joined anyway, he was only 17. The cook is one of the most important crew members because he or she was instrumental in keeping the food from rotting and preparing it which took many hours.