Gabionades are a type of pre-battle deployment option in Empire: Total War and Napoleon: Total War.
General Information[]
When armies stay motionless on the world map for a certain amount of time (one turn for Napoleon and two for Empire) and is attacked, most artillery units gain the ability to place gabionades.
Gabionades are similar to Earthworks. They give artillery crews a measure of protection against enemy fire. Unlike earthworks, however, gabionades come with significant drawbacks. Artillery crews lose their horses, making them immobile for the duration of the battle (unless they abandon their guns). Also, gabionades severely restrict the angles with which a crew can fire from; they essentially can only hit what's in front of them, making them defenceless against flanking attacks. Gabionades thus work best when the enemy are coming at the artillery in a straight line, such as in a valley or between buildings.
One small advantage of gabionades are that the removal of a crew member per artillery piece that would otherwise be seated with the horses effectively grants each artillery piece one extra member to man the guns. This allows artillery regiments to suffer more losses before they are rendered unable to operate their artillery.