Steam Guns are very large white hand-held weapons utilized by the crew of the Silvana.
Steam Guns are mainly wielded by The Mechanics. They are much larger, heavier, and have a slower rate of fire than the hand-held machine guns also wielded by the Silvana crew. However, their increased power allows them to be used effectively against the heavily armored Starfish employed by the Guild. Even so, careful aim is necessary to penetrate the cockpit of the Starfish and kill the pilot; shots to other areas do not necessarily disable them.
Like most non-Guild technology in Last Exile, the Steam Guns are steam-powered.