In game, ships will gain experience, which will upgrade some ships skills, like rotation speed or attack speed.
Experience is gained by destroying targets on the map, with the ships in the fleet. Experience given by a target means to have a certain quantity of points, which are given in the five (or less) ships in the fleet. This quantity is given in function of the participation of the ship. If a ship destroy 100% of the target, it will win ALL the experience. But, even if you do everything, it's very hard to win with only one.