Molasses was used for the crew for most sweetening purposes because it was cheaper than sugar. Butter, before it went bad, was available to the Captain and his officers only.
"Duff" was a common dish for those at sea. Made by boiling flour, lard and yeast in equal parts of fresh and saltwater, sometimes finely chopped salt pork fat was added for flavor. If the crew did not have "duff" and molasses at least once a week, the seamen were disappointed and complaints were usually made.
"Lobscouse" was another favorite made with hard bread and salt meat sprinkled with pepper and chopped into pieces and then boiled in water " Sea pies" or "dough boys" was a dumpling made with flour and the flesh and bones of porpoises caught at sea, which offered a distraction from the salted meats and fish.
The kitchen on board was called a galley which was often on deck. Three meals a day were prepared for everyone in a very tiny space.
Martha's Vineyard Museum