The United States Navy is reclassifying 19 planned Virginia-class submarines fitted with the Virginia Payload Module as guided missile submarines, changing their designation from SSN to SSGN, the service stated.

The change covers Blocks V and VI of the class. It is a designation change rather than a modification, and the boats remain part of the Virginia programme, but it formally separates them from the attack submarines that share the name.

The Virginia Payload Module is an additional hull section inserted into the boat, adding length and four large vertical launch tubes to the two already carried forward. Each tube holds seven Tomahawk cruise missiles, taking the total from 12 in earlier blocks to 40, roughly tripling the strike load a single submarine can carry.

The first of the type, SSGN 803, is estimated to deliver in the 2029 financial year, with deliveries running through to 2038.

Vice Admiral Rob Gaucher, director of submarine programs, said: “This reclassification is a clear acknowledgment of the increased lethality VPM brings to the undersea fight. These VPM-equipped SSGNs will ensure the Navy continues to dominate the undersea domain for decades to come. By integrating this additional payload capacity, we will have the ability to surge strike power to assure our allies, deter aggression, outmatch any adversary, and give our Fleet commanders an incredibly versatile, hard-hitting instrument of national power.”

Admiral Daryl Caudle, the Chief of Naval Operations, tied the announcement to the retirement of the boats the new designation effectively replaces.

He said: “This transition comes at an important moment as USS Georgia, one of the Navy’s four Ohio-class guided-missile submarines, begins the inactivation process after more than four decades of exceptional service. Georgia and her sister ships proved the enduring value of combining undersea stealth with unmatched clandestine strike capability. The next generation of Virginia-class SSGNs builds on that legacy with greater survivability, adaptability, and sustained combat power.”

The four Ohio-class SSGNs were converted from ballistic missile submarines in the 2000s after the arms control treaties then in force required a reduction in the number of boats carrying nuclear weapons. Rather than scrap them, the Navy stripped out the Trident tubes and refitted 22 of them for seven Tomahawks apiece, producing submarines able to carry 154 cruise missiles alongside accommodation for special forces. USS Florida fired more than 90 Tomahawks against Libyan air defences in 2011.

Those boats are now reaching the end of their hulls’ certified lives, and their retirement removes a large slice of the Navy’s undersea strike capacity at once. Nineteen Virginias at 40 missiles each restores the total, though spread across many more platforms.

Vice Admiral Rick Seif, commander of submarine forces, said: “The Submarine Force is defined by our ability to operate undetected and strike without warning. By integrating high-volume precision strike capabilities into these stealth platforms, these SSGNs serve as the ultimate enabler for Distributed Maritime Operations, giving our warfighters the overwhelming, flexible firepower required to win decisively in any theatre.”