Galley division is when a ship is divided into two parts. It's like taking a big room and splitting it in two with a wall. The two parts are called port and starboard and they are separated by the galley, which is the kitchen area. The galley divides the two parts so that one side (port) can focus on doing the sailing and the other side (starboard) can focus on cooking and cleaning. This helps to make the ship run more efficiently and quickly.