Abstract: A retrofitable breech is disclosed for use on existing tubes for launching vehicles, such as torpedoes. The breech utilizes gas generators such as commercial off the shelf automotive airbag inflators, for propelling the torpedo from the tube. A plurality, typically three or four, generators are used and are fired in sequence with a controlled time delay. A retrofitable device is also disclosed for activating the weapons securing mechanism to release the torpedo. In addition, a release mechanism is disclosed for pulling the electrical connector plug on the torpedo. The sequence of releasing the torpedo, retraction of the plug and firing the inflators is controlled by a controller upon initiation of the firing sequence.