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Regular firing and directional exercises involving dummy torpedoes are done to get the crew mission-ready. These dummy torpedoes don’t have explosives inside of them which means the crew has to get them back after the exercise. Helicopters and divers are sometimes used during retrieval.
If the budget permits it, the SINKEX program is used to train the crew. SINKEX (Sink Exercises) are used by the US Navy to evaluate weapon lethality, ship survivability, multi-unit tactics, and more. In these exercises, stripped decommissioned ships are used for target practice. The participants are expected to use real ammunition to sink the ship which could cost upwards of 10 million dollars.
One of the torpedoes featured in the video is a Mark 48 carried by all USN submarines. It can be guided by the submarine through the wires attached to it. The Mk-48 also has its own active/passive sensors to execute such attacks. This 3,600 lb and 19 ft long torpedo can even circle back once more if it misses.