The USS Milwaukee, a littoral combat ship that was commissioned less than a month ago, became stranded at sea after suffering a propulsion problem. It had to be towed more than 40 nautical miles to the Joint Expeditionary Base at Little Creek, Va.

After being commissioned in Milwaukee, the vessel was on its way to its new home port of San Diego. The ship had already navigated through the Great Lakes of Michigan, passed by Halifax, Canada and chugged south towards Florida before it began to malfunction. The Navy stated that the breakdown was caused by “fine metallic debris in the port combining gear filter system” that caused a “loss of propulsion.”

The USS Milwaukee cost $437 million to build, but critics have long claimed that the ship hadn’t met the expectations of that high price tag. The vessel was touted as “truly unstoppable” by Commander Mark Haney–until it broke down at sea a mere 20 days after its commissioning.

Sen. John McCain expressed that he found the ship’s “complete loss of propulsion … deeply alarming, particularly given this ship was commissioned just 20 days ago. “U.S. Navy ships are built with redundant systems to enable continued operation in the event of an engineering casualty, which makes this incident very concerning.”

You can see how the USS Milwaukee is supposed to function in this video of the vessel’s October acceptance drills.