A canister that acts as a pressure vessel that contains a payload and that can withstand pressures that may be generated by the payload internal to the canister in order to contain the payload contents. The canister can be launched from a submarine, with the canister being located internal to the pressure hull of the submarine prior to launch and the canister being launchable from the submarine into the surrounding water. After launching, the canister is designed to release or deploy the payload permitting the payload to perform its intended function(s). The payload contained in the canister can be an unmanned underwater vehicle such as an acoustic training target that is powered by one or more lithium batteries.