Abstract: An explosive device contains a water-reactive material that ignites upon exposure to water. The water-reactive material ignites a water-activated fuse that has a predetermined burn rate and length. The predetermined burn rate and length allows the device to sink to a desired depth before exploding. Hence, the device explodes after a desired period of time and/or at a desired depth. Defense against underwater swimmers is an advantageous feature of embodiments of the disclosure. The device can use a forty millimeter (40 mm) form factor, which permits launch of the device from convention grenade launchers.

Abstract: An underwater grenade and a method for using an underwater grenade. A depth activated, hand emplaced ordnance utilizing safe and arm technology to address underwater threats (such as enemy swimmers) while providing a safe interface with personnel. The grenade is armed after a sequence of events have occurred including reaching a desired depth and a desired passage of time. Failure of any of the events to occur will cause the grenade to be rendered safe.

Abstract: A pressure-actuated fuse has a housing formed with an inner chamber and with a passage having an outer end opening to the exterior and an inner end opening into the chamber. A plug in the passage has a porosity sufficient to allow slow liquid flow through itself. An actuating element is exposed inwardly in the chamber and outwardly to the exterior and is displaceable in the housing by a pressure differential between the chamber and the exterior along an actuating axis between an outer position and an inner position. The chamber is substantially closed to the exterior except through the passage. A valve in the passage connected to the actuating element blocks liquid flow along the passage only when the actuating element is in its outer position. Thus, when the element moves out of its outer position liquid can flow through the plug and limitedly along the passage into the chamber.

Abstract: An underwater ignition device is provided comprising a rotor, a detonator disposed at the rotor, a locking pin secured in position by a safety pin, a release pin maintained in position by the locking pin, a first water pressure safety device normally engaging the rotor and preventing a rotating motion of the rotor into an ignition position and a second water pressure safety device actuable after the locking pin is removed and after the first water pressure safety device has been actuated and capable of actuating the release pin for rotating the rotor into an ignition position. An ignition circuit employed comprises a digital logic connected to an analog receiver, dual driver stages connected to the digital logic, parallel discharge circuits connected to the dual driver stages and to a detonator and the voltage supply and suitable for selectively igniting the detonator or for short circuiting the voltage supply. The digital logic actuates two discharge circuits in successive time intervals (t.sub.1,t.sub.2,t.

Abstract: A fuse apparatus for a depth charge or the like has a primary fuse that operates at a relatively shallow depth to position a detonator in line with a firing pin, and a secondary fuse that operates to release the firing pin to explose the detonator. A safety mechanism normally prevents operation of the primary fuse, but can be canceled to allow such operation. The secondary fuse cannot itself operate until the primary fuse has operated, so that the two fuses must operate successively to set off the detonator. In addition the two fuses operate along mutually perpendicular axes, so accidental jarring of the device cannot set it off. Finally the arrangement is constructed to leak slightly so that in the event it fails to go off it will rapidly become inoperative.