US Navy's new Atlas floating drydock to launch America’s largest nuclear submarines.

The Atlas floating dry dock, built by Bollinger Shipyards in cooperation with General Dynamics Electric Boat, was christened in Tampa, Florida, on October 10, 2025. The dock will be used to handle the construction and launch of Columbia-class submarines, the largest nuclear subs ever built by the U.S.

On October 10, 2025, Bollinger Shipyards and General Dynamics Electric Boat christened the floating dry dock Atlas in Tampa, Florida, which was created to handle the construction and launch of Columbia-class ballistic missile submarines, the largest nuclear-powered submarines ever built in the U.S. The dry dock will provide construction and launch support at Electric Boat’s South Yard Assembly Building in Groton, Connecticut, aligning with final assembly bays to handle modular submarine sections. Official statements confirmed that Atlas will begin operational integration following completion of dredging and site preparation in 2025.
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The floating dry dock Atlas will be essential to the Columbia-class program, providing the specialized launch and maintenance capacity needed to assemble, service, and sustain the U.S. Navy’s next-generation ballistic missile submarines. (Picture source: Bollinger Shipyards)

Measuring 188 meters (618 feet) in length and 43 meters (140 feet) in width, Atlas is designed to provide essential dry dock capacity for construction, maintenance, and long-term sustainment of the U.S. Navy’s Columbia-class ballistic missile submarines. The event, followed by official statements on October 13, underlined its importance as part of the industrial base supporting the Columbia-class, which will replace the Ohio-class submarines as they retire beginning in 2027. The Columbia-class will become the largest submarines ever built by the United States, measuring approximately two and a half times the size of the Virginia-class attack submarines, and will form the sea-based leg of America’s strategic deterrent for decades.

A floating dry dock is a submersible U-shaped structure composed of watertight pontoons and side walls equipped with ballast tanks that can be flooded or emptied to control buoyancy. When a ship requires maintenance or construction work, the dock submerges by filling its ballast tanks with water, allowing the vessel to be positioned above the central deck area. Once aligned on the dock’s keel blocks, the tanks are pumped dry, causing the dock to rise and lift the vessel completely out of the water, exposing the hull and propellers for repair, cleaning, or fitting operations. This method provides precise control over trim and stability, ensuring that large ships remain level during lifting. Many floating dry docks consist of multiple joined sections that can be configured according to the size of the ship or submarine. They are often fitted with cranes, power generation systems, and repair workshops to enable complex technical work on board, reducing the need for external facilities. The modular structure allows flexibility in operation, while the self-ballasting mechanism provides accurate adjustment of buoyancy during every phase of the docking and launching process.

Floating dry docks such as Atlas are essential for the U.S. Navy because they provide mobile and scalable infrastructure for both surface ships and submarines, including the Columbia-class. They make it possible to conduct construction, overhaul, and emergency repair work without relying solely on fixed graving docks, which are limited in number and location. For nuclear-powered submarines, a floating dry dock offers the ability to lift extremely heavy hulls for maintenance of propeller shafts, hull coatings, and underwater fittings, ensuring operational readiness for deterrence patrols. For surface vessels such as destroyers, amphibious ships, and support craft, they provide a means to carry out rapid repairs close to operational areas, avoiding long transits back to major shipyards. Their sectional construction enables deployment to various naval bases and shipyards, including Groton, Pearl Harbor, and overseas support locations, depending on mission needs. By maintaining and restoring hull integrity, propulsion systems, and other submerged components, these structures sustain fleet availability and extend service life.

As a critical component of the US Navy’s industrial base, Atlas will operate as a self-ballasting floating dry dock designed to align with either of the two final assembly bays of Electric Boat’s South Yard Assembly Building (SYAB) in Groton, Connecticut. Once modules or a completed submarine are rolled aboard, the dock can translate westward to a dredged sinking basin for launch operations. This process eliminates the need for the crossover rails and directional changes used in earlier graving dock configurations, streamlining launch procedures. Approximately 688,000 cubic meters (900,000 cubic yards) of dredging are scheduled between 2024 and 2025 to prepare the sinking basin. The self-ballasting system enables Atlas to compensate automatically for weight changes during roll-on operations by adjusting its buoyancy in real time, ensuring stability and precision during the handling of large submarine sections.

The South Yard Assembly Building was developed specifically to accommodate the Columbia-class production process and represents a major infrastructure upgrade at Electric Boat’s Groton facility. Measuring 190 meters by 95 meters (624 feet by 313 feet), it includes three heated bays—two for final assembly and one for module construction—along with two 91-ton (100-ton) cranes, one 154-ton (170-ton) crane, and two 36-ton (40-ton) cranes for mezzanine operations. The uniform floor load capacity and open-span design allow the building to support the heavy modular construction approach adopted for the Columbia-class program. Modules arriving from Quonset Point are offloaded using self-propelled modular transporters rated at 54 tonnes per axle (60 tons per axle), replacing previous 36-tonne-per-axle (40-ton-per-axle) systems to accommodate the heavier Columbia modules. The building’s straight-through configuration allows direct rollout to Atlas positioned along its southern face.

Bollinger Shipyards’ construction of Atlas follows a sequence of previous collaborations with Electric Boat that strengthened the industrial supply chain for submarine construction. In 2019, Bollinger was awarded the contract to build the 122-by-30-meter (400-by-100-foot) ocean transport barge Holland, which was delivered on schedule in 2021. The Holland is a self-ballasting barge with a payload capacity of 4,990 tonnes (5,500 tons) designed to move Columbia-class and Virginia Payload Module sections between Electric Boat’s Quonset Point, Newport News, and Groton facilities. Its design replaced earlier jacking-style barges, which had capacity limitations, and introduced simultaneous ballast compensation during roll-on and roll-off operations. Bollinger is also constructing a pontoon launcher to further support the Columbia-class submarine program, adding another modular infrastructure element for the assembly and launch phases. The Colombia-class's construction and assembly activities are divided between Electric Boat’s facilities in Groton and Quonset Point and Newport News Shipbuilding, maintaining a continuous production tempo to meet scheduled fleet replacement and sustain the Navy’s strategic deterrent capability well into the 2080s.

Electric Boat serves as the prime contractor for the Columbia-class, responsible for the design, integration, and overall production of the submarine fleet. Submarines of the class are being built to succeed the Ohio-class fleet that entered service in the 1980s, which is approaching the end of its operational life. The lead submarine, USS District of Columbia (SSBN 826), is expected to begin service in the early 2030s, followed by two other submarines to date, the USS Wisconsin (SSBN-827) and the USS Groton (SSBN-828), assembled under a “two-plus-one-year” production rhythm coordinated with the Virginia-class program, creating increased demand for specialized facilities such as Atlas. Each Columbia-class submarine will measure about 171 meters (560 feet) in length, with a beam of 13 meters (43 feet) and a submerged displacement of approximately 20,800 tonnes, making it the largest submarine ever built by the United States. This future class will incorporate 16 missile tubes for Trident II D5LE ballistic missiles, an electric-drive propulsion system replacing the mechanical reduction gears used in previous classes, and a reactor designed to last the vessel’s entire 42-year service life without refueling.

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.