This is a promotion which the player, or an AI can choose for a Galley, Trireme or pretty much any other ship, or naval unit. This promotion does not really require Never though it says to. This is a promotion one should choose if one wants a ship that moves fast on the sea. The opposite promotion of this makes the ship's movement slower as this will keep the ship's movement untouched. This means that a Galley will move at a standard of two tiles per turn, with this it will still be two. A Trireme moves at the standard of one tile per turn, with this it will be the same.