USS Vermont Block 4 submarine commissioned by US navy


The U.S. Navy commissioned USS Vermont (SSN 792), the 19th Virginia-class attack submarine on April 18, 2020. The traditional public the commissioning ceremony was canceled due to the current situation, the U.S Navy commissioned USS Vermont administratively and transitioned the ship to normal operations. Acting Secretary of the Navy James E. McPherson said, “This Virginia-class fast-attack submarine will continue the proud naval legacy of the state of Vermont and the ships that have borne her name. 

Virginia Class Submarine

I am confident the crew of this cutting edge platform will carry on this tradition and confront the challenges of today’s complex world with professionalism and dedication our nation depends on from warriors of the silent service.” Vice Adm. DarylCaudle, commander, Submarine Forces, said Vermont’s entry to service marks a new phase of American undersea warfare dominance for a global Submarine Force that is ready to deter, defend and defeat threats to our nation, allies, and rules-based international order. 

In this article, Defence Talks analyzes, why the addition of USS Vermont will significantly improve the US Navy’s offensive capability? Let us get into the details. 


The Virginia class sometimes referred to as SSN-774 class, is a class of nuclear-powered fast attack submarines in service with the United States Navy. Virginia class is designed to replace older Los Angeles-class submarines, many of which have already been decommissioned. Virginia-class submarines will be acquired through 2043, and are expected to remain in service till 2070. Virginia-class submarines are designed for a broad spectrum of open-ocean and littoral missions. Their primary purpose is to take out enemy's surface combatants and submarines and the secondary task is to execute land-attack missions. 

Virginia-class submarines were the first US Navy warships designed with the help of computer-aided design (CAD) and visualization technology CATIA. Each submarine is projected to make 14–15 deployments during its 33-year service life. The Virginia class was intended in part as a less expensive alternative to the Seawolf-class submarines ($1.8 billion vs $2.8 billion), whose production run was stopped after just three boats had been completed. To reduce costs, the Virginia-class submarines use many "commercial off-the-shelf" (COTS) components, especially in their computers and data networks. 

In practice, they actually cost less than $1.8 billion each, due to improvements in shipbuilding technology. The Virginia class is built through an industrial arrangement designed to maintain both GD Electric Boat and Newport News Shipbuilding, the only two U.S. shipyards capable of building nuclear-powered submarines. Under the present arrangement, the Newport News facility builds the stern, habitability, machinery spaces, torpedo room, sail, and bow, while Electric Boat builds the engine room and control room. The facilities alternate work on the reactor plant as well as the final assembly, test, outfit, and delivery. 


USS Vermont has been build by shipbuilder General Dynamics Electric Boat in Groton. It has a length of 115 m. To give viewers a perspective, its length is slightly greater than that of a football field. It displaces around 7,900 tons. USS Vermont like all other Block IV subs is acknowledged to be able to move to depths of 240m (800 feet) but allegedly capable of going down to 490 m (1,600 feet). A single S9G reactor that produces around 30 MW powers Vermont. 

The reactor features improved corrosion resistance and reduced life-cycle costs. It also has reduced size and weight enabling the submarine to pack more weapons and sensors. The S9G reactor is designed to operate for 33 years without refueling. So USS Vermont has a practically unlimited range, limited by only food supplies and maintenance requirements. The reactor produces enough power to propel Vermont over 25 knots that are 46 km/hr or 29 mph, though the actual numbers may be significantly higher. 


Block IV consists of 10 submarines. On 28 April 2014, the most costly shipbuilding contract in history was awarded to General Dynamics Electric Boat as the prime contractor. The deal for ten Block IV Virginia-class attack submarines were worth $17.6 billion The main improvement over the Block III is the reduction of major maintenance periods from four to three, increasing each ship's total lifetime deployments by one. So, the Block IV variant will be capable of a total of about 15 deployments. \SENSORS

The Virginia class is the first to use photonic sensors instead of a traditional periscope. The class is equipped with high-resolution cameras, along with light-intensification and infrared sensors as well as an infrared laser rangefinder. Block IV variant of Virginia-class is has redesigned elements and feature several types of sonar arrays. 

1. It incorporates a Large-Aperture Bow (LAB) water-backed array, which replaces the traditional air-backed spherical array. This is main sonar is one of the most powerful sonars mounted in any of the submarines in the world. 

2. Two high-frequency active sonars mounted in the sail and bow. These supplements the main sonar array improving anti-submarine warfare performance. 

3. A fiber optic sonar array, consisting of 3 flat panels is present on either side of the hull. 4. For coverage above and behind the submarine, a High-frequency sonar is mounted on both sides of the submarine’s sail. USS Vermont is also equipped with a low frequency towed sonar array and a high frequency towed sonar array. 


USS Vermont will be deadly as it is packed with different kinds of weapons to knock out varied targets. 1. Two large-diameter Virginia Payload Tubes, each capable of launching 6 Tomahawk cruise missiles. Tomahawk is a long-range, all-weather, cruise missile that is used for land-based attacks. It has a long-range of 1,000 mi or 1,700 km, enabling them to be launched from far off. 2. Four 533 mm torpedo tubes for the Mk-48 torpedo. There is a capacity to carry up to 26 Mk-48 torpedoes in the weapon's chamber. 

These torpedoes have a range in excess of 50 km or 31 miles and can be used to take out enemy submarines and surface vessels. 3. Like all Virginia class, Vermont can also lay different types of mines including the MK-60 CAPTOR Encapsulated Torpedo mines. 4. An integral lock-out/lock-in chamber is incorporated into the hull for special operations. The chamber can host a mini-submarine, such as Northrop Grumman’s Advanced SEALS Delivery System that can be used to transport special warfare forces such as Navy SEAL teams. 


The main adversaries of the U.S, Russia & China are going ahead with the construction of several new subs. Russia plans to build a total of 8 Yasen M class submarines which are intended to destroy US aircraft carriers. The latest Kilo-class submarine of the Russian fleet is also a force to take note of. Though Kilo-class is nothing new and has even around in some form or another since the 1980s, the newest 6 submarines of this class represent a significant evolution.

Russia is also building the Borei class which will be Russia’s new generation of ballistic missile submarines — the cornerstone and most survivable part of its nuclear arsenal. Chinese Navy has been given special attention and is getting a good share of the military budget. It is developing a wide range of conventional as well as nuclear powered submarines. It is clear that the U.S Navy needs to be a step ahead and USS Vermont being a multi weapons platform will significantly improve the offensive capability.  

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