Northrop Grumman The torpedo can attack submarines or torpedoes. Unlike previous lightweight torpedoes, the VLWT will be used by aircraft, surface ships, and submarines. The U.S. Navy plans to field its first new torpedo in decades, and one candidate is Northrop Grumman's Very Lightweight Torpedo (VLWT). Originally designed to protect aircraft carriers from incoming torpedoes, VLWT could be used by aircraft, surface ships, and even submarines. The weapon can be used both as an offensive weapon against enemy submarines, or a defensive one against inbound torpedoes. ➡ The VLWT, according to National Defense, was originally designed to defend the Navy’s aircraft carriers from submarines. Installed on carriers, the mini-torpedoes would be launched at the first sign of enemy attack, homing in on the incoming torpedoes.