The Virginia-class submarines utilize pump-jets rather than conventional screw propellers, which are quieter but must be built carefully. BAE Systems says it is up to the task.

The US Navy will pay multinational defense giant BAE Systems almost $138 million to manufacture new pump-jet propulsor assemblies for the US Navy’s Virginia-class nuclear-powered attack submarines (SSNs), BAE announced in a news release. 

The award is valued at approximately $137.66  altogether, with the Naval Surface Warfare Center Carderock Division identified as the contracting organization. The contract covers production, engineering services, replacement parts, and associated support for an ordering period that extends through September 2032.

The propulsors are a key part of the Virginia-class submarine’s propulsion system. Rather than a conventional exposed screw propeller, the Virginia class uses pump-jet propulsion, which is quieter and harder for enemy submarines or listening stations to detect. Pump-jets incorporate a rotor and stationary flow-conditioning components within a surrounding duct or shroud. Conventional propellers can produce “cavitation,” or low-pressure bubbles that collapse and generate underwater noise; pump-jets are designed to manage water flow in a way that reduces certain noises and generally improves the acoustic performance of a submarine.

Modern submarine warfare depends heavily on detecting an opponent before being detected. For that reason, precision manufacturing is essential. Any sort of imperfection in the propulsor can create vibrations and unwanted acoustic signatures that can compromise detection advantages, and whichever contractor is building the propulsors must do so within exceedingly tight tolerances.

The Navy has relied on BAE Systems for that role before; indeed, the UK-based company has delivered major propulsor assemblies for every Virginia-class submarine built to date. In its media statement announcing the contract, the company noted that it had met the Navy’s target of two Virginia-class propulsor sets annually, with manufacturing and engineering operations located in Kentucky, Florida, and Minnesota. BAE states that it has invested its own capital in facilities and workforce development toward meeting the contract.

Why Does the Navy Still Care So Much About the Virginia-Class Submarine?

The new propulsor contract is intended to support the Navy’s “1+2” submarine production cadence—by which it plans to commission one cutting-edge Columbia-class nuclear-powered ballistic-missile submarine (SSBN) and two older Virginia-class nuclear-powered attack submarines per year. In recent years, Virginia-class production has fallen well short of the two-per-year objective, with recurring problems including skilled labor shortages, supplier constraints, and shipyard capacity problems. Improving propulsor development would likely improve the production cadence of Virginia-class boats, as propulsors are specialized, long-lead components that must be ready before final submarine assembly.

The Navy needs Virginia-class submarines because the platform is central to American undersea warfare; it performs intelligence collection, anti-submarine warfare, anti-surface warfare, and land-attack missions. The newest Block V Virginia submarines introduce the Virginia Payload Module (VPM), an approximately 84-foot hull section containing four additional large-diameter missile tubes—effectively transforming the SSNs into non-nuclear ballistic missile submarines (SSGNs). VPM-equipped submarines can carry up to 28 additional Tomahawk missiles, which expands strike capacity and helps to close the missile gap between the US and China. But because the Virginias are larger and more capable, this places more demands on the platform’s propulsion efficiency and acoustic performance.

The Virginia class is also important because the Navy is actively working to replace the aging Los Angeles-class submarines, a Cold War-era design. The new contract is about maintaining a dependable domestic supplier base to both accelerate and sustain submarine production at a time when undersea competition with China increases.

The $138 million award does not resolve the Navy’s submarine production shortfall. But reliable delivery of specialized propulsion components is essential to increasing construction rates. Sometimes maintaining a production schedule comes down to relatively niche parts and niche construction processes. The contract should help BAE deliver high-quality propulsion components efficiently and steadily.

About the Author: Harrison Kass

Harrison Kass is a writer and attorney focused on national security, technology, and political culture. His work has appeared in Tablet, City Journal, The Hill, The Spectator, and The Cipher Brief. He holds a JD from the University of Oregon and a master’s in Global & Joint Program Studies from NYU. More at harrisonkass.com.

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