The US Navy's struggle to keep ships in fighting shape is leading sailors to 'cannibalize' more parts from other ships

• Shortages of spare parts is driving US sailors to take more and more parts from other ships.
• As a result, more ships are down for maintenance and unable to perform missions, a government watchdog says.

The US Navy is so short of spare parts that crews are increasingly taking a drastic step: Cannibalizing parts from some ships to keep other ships going.

The result is more ships that are down for maintenance and unable to perform their missions, according to a report submitted to Congress by the Government Accountability Office. The spare parts shortage only exacerbates an already dismal Navy maintenance situation, with overburdened and understaffed shipyards unable to perform necessary overhauls on schedule.

Navy officials told the GAO that "surface ships have experienced an increasing number of cannibalizations over the past few years. There are many contributing factors depending on the specific equipment or ship system, but most are due to increased demand for material that is not readily available."

The GAO examined 10 classes of ships that accounted for 153 of the Navy's 292-strong battle force. Out of those 10, nine suffered from increased cannibalization between 2015 and 2021, with littoral combat ships the worst affected.

For Nimitz-class aircraft carriers, which make up almost all of the US carrier fleet, scrounging used parts has been "driven by combat systems-related equipment," the GAO said. "Many of these parts are older and no longer being produced by manufacturers so they are hard to obtain."

Only the new America-class amphibious assault ships, of which only two are in service, experienced a decrease in cannibalized parts by 2021.

The study listed a cascade of causes for the shortage of spare parts: "Parts obsolescence, diminishing manufacturing sources, and material shortages are common issues." In addition, the COVID-19 pandemic disrupted supply chains.

Nor does industry have an incentive to make parts for older equipment. Navy officials told the GAO that "manufacturers for these parts require demand to continue to produce the parts, and it is not economically feasible for them to remanufacture until they receive this demand."

One possible cause that the study did not have a chance to examine was lack of Navy planning for unexpected maintenance.

"We know from some of our other work on maintenance that the Navy has had a significant problem with unplanned work," Diana Maurer, director of the GAO's Defense Capabilities and Management Team, told Insider. If a ship comes in for scheduled repairs, and an unexpected problem is discovered, the right parts may not be available.

Congress has sometimes blocked the retirement of ships that the Navy doesn't want anymore. One consequence is that spare parts must still be found for those aging vessels.

Swapping parts between automobiles is nothing new for backyard mechanics. Likewise, militaries have long cannibalized equipment during operations when spare parts may not be available.

But routinely swapping spares to keep large numbers of complex weapons operational is not a viable solution. For example, a 2022 GAO study of aircraft sustainment found that multiple types of planes — including B-2 stealth bombers and C-17 cargo aircraft — required cannibalization of some planes to keep others flying.

In the case of the C-17, "when a part was cannibalized, it often added a day or two to the total time an aircraft was not mission capable," Air Force officials told the GAO. A 2001 GAO report found that cannibalized parts created higher workloads for mechanics and lower morale for personnel who have to make these improvised fixes work.

The new report marks the first time GAO has tried to assess how often Navy surface ships are sufficiently maintained to fulfill their missions. The problem is that unlike for military aircraft, the Navy hasn't tracked the mission-capable rate for ships (though it may do so in the future).

This forced GAO investigators to determine mission readiness by aggregating several indirect indicators, including cannibalization rates, steaming hours at sea, and ships reporting that they couldn't perform their missions.

Of the 10 ship classes the GAO analyzed, eight saw increased category 3 and 4 casualty reports, which mean a vessel cannot perform some missions. The most trouble-prone was the Wasp-class amphibious assault ship, which experienced 18 category 3 and 4 reports in 2011 — and 43 in 2021.

Steaming hours have also declined for Navy ships, though by how much isn't clear, as the Department of Defense has classified the data. Not surprisingly, lack of parts and fewer steaming hours have contributed to rise in costs per steaming hour, making it more expensive to keep a ship at sea.

Interestingly, fewer steaming hours for Navy ships may indicate a lack of money as much as it points to maintenance problems. Navy officials told the GAO that "steaming hours are an indication of the financial health of the fleet and allocation of steaming hours is driven by budgetary concerns and the cost of fuel."

Either way, the maintenance situation appears to be getting worse. In September 2022, a senior Navy maintenance officer admitted that on-time maintenance for surface ships in 2022 had declined to 36% from 44% in 2021.

"We are going in the wrong direction with regard to on-time delivery," said Rear Adm. Bill Green, fleet maintenance officer for US Fleet Forces Command.

While Navy maintenance problems are obvious, solutions are not. In particular, ensuring production of spare parts for older ships, aircraft, and other platforms presents a chicken-and-egg challenge: Manufacturers won't keep production lines without sufficient demand, and legacy weapons generate less demand as they are replaced by new systems.

"If there are only 10 ships in a particular class, and they're really old and the Navy keeps saying they want to retire them, why would a manufacturer want to stay in the business of making parts for them?" Maurer said.

Michael Peck is a defense writer whose work has appeared in Forbes, Defense News, Foreign Policy magazine, and other publications. He holds a master's in political science. Follow him on Twitter and LinkedIn.