Is there a setting for slowly killing units that are outside a city or military base?

In Freeciv, is there a setting that slowly kills units that are outside a city or military base? For example, when I send a battleship halfway across the world, it should be slowly killed until it is "refueled" in a city. I know that there is a setting to slowly kill starting units that have no home city, but here I want to slowly kill all units that are outside a city or military base.