Delays at naval shipyards caused by supply-chain issues and not enough workers have put nearly 40% of Navy attack submarines out of commission, according to a July 6 report from the Congressional Research Service. The Navy prefers that only about 20% of its submarines be in depot maintenance at any time, according to the report. Eighteen of the Navy’s 49 nuclear-powered attack submarines are classified as in depot maintenance or awaiting maintenance, which leaves the U.S. at a critical disadvantage against China’s larger fleet, according to Bloomberg. Excluding 2021, when the Navy similarly had only 31 operationally ready attack submarines, the service hasn’t had so few operational submarines since at least 2008, according to the report. U.S. submarines, which can fire torpedoes and Tomahawk cruise missiles, are seen as a key advantage over China’s numerically superior navy.