U.S. Navy eyes Coast Guard cutter as new frigate class after Constellation cancellation.

The U.S. Navy is considering the Coast Guard’s National Security Cutter as the basis for a new frigate class following the cancellation of most of the Constellation-class program ships.

On December 12, 2025, Breaking Defense reported that the U.S. Navy is considering the Coast Guard’s National Security Cutter (NSC) as the basis for a new frigate class following the cancellation of most of the Constellation-class program. Private remarks attributed to U.S. Navy Secretary John Phelan point to a preference for an American-designed hull and stricter limits on design changes as an effort to control requirements growth, shorten development timelines, and field the first ship of the new class by 2028.
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The Legend-class, or National Security Cutter (NSC), is a U.S. Coast Guard cutter designed for long-range patrols, extended endurance operations, and multi-mission maritime security tasks, rather than high-end naval combat. (Picture source: US Coast Guard)

A U.S. Navy spokesperson has declined to expand on the private-dinner remarks beyond pointing to the secretary’s public comments, in which Phelan has emphasized that the replacement should be an American-designed vessel and that he wants tighter control over future change orders, including a requirement that any major changes receive direct approval at the highest level. U.S. Navy acquisition leadership has linked this approach to a broader effort to shorten timelines by stabilizing designs before construction begins, with the stated objective of having the first ship of the new frigate class in the water by 2028. The approach reflects a certain dissatisfaction with past practices that allowed requirements to evolve during construction, contributing to delays and cost growth. Taken together, the remarks and potential cutter adaptation suggest the U.S. Navy is now prioritizing speed, predictability, and industrial stability as it resets its frigate strategy.

The Constellation-class originated as the FFG(X) program, which was intended to deliver a new class of frigates to the U.S. Navy capable of escort missions, air defense, and anti-submarine warfare while easing operational demand on larger destroyers. In April 2020, the Navy awarded Fincantieri Marinette Marine a $795 million contract covering detailed design and construction of the lead ship, with options that supported an initial multi-ship procurement. The selected design was derived from the Franco-Italian FREMM, and early planning emphasized limiting changes to preserve schedule and cost discipline. Over time, the Navy expanded the program to six contracted ships, while longer-term force planning anticipated at least 10 hulls in the first production tranche. The program was framed as a way to rapidly introduce a modern frigate by leveraging an existing design rather than pursuing a clean-sheet development.

As the Constellation-class matured, the level of modification increased substantially, eroding the benefits of using a parent design and introducing compounding challenges. By 2025, the ship was described as sharing only about 15% commonality with the FREMM baseline, effectively transforming it into a largely unique platform. Construction progress on the lead ship was reported at roughly 10% complete as of April, and the projected delivery timeline had slipped to 2029, well beyond original expectations. Cost estimates followed a similar trajectory, moving from early figures around $1 billion per ship toward estimates closer to $1.4 billion. These outcomes reinforced concerns within Navy leadership that the program’s structure enabled repeated design changes, which in turn drove delays and higher costs that were difficult to reverse once construction was underway.

In parallel, on June 5, 2025, the Department of Homeland Security announced the cancellation of the construction of an 11th Legend-class cutter: this means the NSC production line is not currently structured as an ongoing program, making Navy decisions particularly consequential for industrial continuity. The decision to cancel most of the Constellation-class, as only two of these frigates are expected to remain, has immediate implications for the U.S. Navy’s force structure and operational planning. The service stated that it would terminate, for convenience, the final four ships that had not begun construction, while continuing work on the first two hulls, as their future status remains under consideration. This outcome leaves the U.S. Navy without the scalable frigate class it had planned to field, increasing reliance on existing surface combatants to fulfill escort and presence missions.

At the same time, the Navy must manage the industrial consequences of truncating a major program, particularly at the Marinette shipyard, where workforce stability and supplier continuity became central concerns. The cancellation of the Constellation-class not only forces the U.S. Navy to identify a replacement quickly, but it also effectively creates a narrower acquisition path in which schedule discipline becomes more critical. This means the service must front-load design decisions, limit requirements growth, and accept tradeoffs earlier than usual, because there is little margin to absorb delays without affecting force structure. If problems emerge during development of the replacement frigate, the Navy would have fewer immediate options to fall back on, particularly given that destroyer production is already heavily tasked and optimized for different mission priorities. In this sense, the cancellation forces a more decisive and less iterative approach than the Navy has often taken in surface combatant programs.

At the same time, the absence of a parallel or hedge program increases the consequences of setbacks during the transition period. With the Constellation-class truncated and no alternative frigate class already in production, the Navy will have to rely on existing surface combatants to cover escort, patrol, and presence missions for longer than planned. These places added operational demand on destroyers, which are more expensive to operate, but also on the National Security Cutter (NSC) itself, as the cancellation of the 11th hull in June 2025 confirmed that the production line was not being kept warm for incremental expansion. As a result, if an NSC-derived frigate were to encounter integration or cost issues, the Navy would risk a production gap rather than a smooth transition. This forces the U.S. Navy to ensure that the selected class is mature enough to absorb modifications without triggering cascading redesign, because there are now fewer safety nets.

However, a frigate derived from the National Security Cutter could make sense in terms of rapidness, as it starts from a hullform that is already built in the U.S. and has accumulated operational experience in extended deployments. The Legend-class/NSC is currently a cutter of roughly 4,600 long tons, measuring 418 ft in length with a 54 ft beam and a 22.5 ft draft, and it uses combined diesel and gas propulsion that includes an LM2500 gas turbine. Performance figures commonly associated with the class include speeds above 28 knots, an advertised range of about 12,000 nautical miles, and endurance cycles of 60 to 90 days. In its Coast Guard configuration, the ship is equipped for a broad mission set and is typically described as carrying a 57 mm gun and Phalanx CIWS, along with sensors and data links intended to support situational awareness and interoperability. These baseline characteristics form the starting point for any Navy-specific adaptation.

Adapting the NSC into a Navy frigate would require careful decisions about combat system integration, because each added capability affects displacement, power margins, and overall ship balance. Industry concepts previously associated with NSC-based patrol frigates illustrate the range of possible modifications, from relatively limited changes to more extensive variants. One such concept, often referred to as Patrol Frigate 4921, was described as adding a 12-cell Mk 56 launcher for ESSM, upgrading the main gun to a 76 mm Super Rapid, integrating Harpoon launchers and a torpedo launcher, and modifying sonar arrangements to include a towed array. These additions were associated with a reduction in range from 12,000 to about 8,000 nautical miles, highlighting the tradeoffs between combat capability and endurance. For the US Navy, the challenge would be to define a stable configuration early, because reopening design decisions during construction would risk recreating the problems perceived with the Constellation-class.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.