US Navy officially names future Virginia class submarine USS San Francisco.

According to information published by the US DoD on October 3, 2023, during Fleet Week San Francisco, Secretary of the Navy Carlos Del Toro revealed that the upcoming Virginia-class nuclear-powered attack submarine, SSN 810, will officially be christened the USS San Francisco.
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Christening ceremony of the Virginia class nuclear-powered attack submarine USS Iowa. (Picture source: Dvids)

Among the advancements of the Virgin class submarines are new propulsion designs that aren't limited by a central shaft, externally launched weapons like torpedoes, alternatives to the traditional spherical sonar array, and technologies that simplify or entirely eliminate certain submarine hull, mechanical, and electrical systems. Efforts were also made to automate standard tasks to decrease the crew's workload and introduce Unified Modular Masts.

Virginia-class submarines were the first to feature masts based on a universal design known as the Universal Modular Mast (UMM), crafted by L3 KEO, previously Kollmorgen.

This design promotes component sharing and some shared design choices between different masts. The first UMM was used in the USS Memphis, a Los Angeles-class submarine.

The UMM is a holistic system designed to house and support submarine mast-mounted antennas and sensors. Included in the UMMs are snorkel masts, photonic masts, communication masts, high-data-rate satellite communication masts by Raytheon, a radar mast, and an electronic warfare mast.

A significant innovation in the Virginia class is the use of photonic sensors rather than traditional periscopes. This class is fitted with high-resolution cameras, light-intensification, infrared sensors, an infrared laser rangefinder, and an integrated Electronic Support Measures array.

Photonic masts, which don't pierce the pressure hull, allow the submarine's control room to be placed within the pressure hull, not necessarily under the sail.

In a departure from traditional optical periscopes which pierced the pressure hull and could compromise structural integrity and increase flooding risks, photonic masts offer a safer alternative.

However, their unique appearance means that when the submarine is detected, it's easily identified as a Virginia-class vessel. Therefore, there are plans to replace the current photonic masts with ones that resemble traditional submarine periscopes more closely.

In propulsion, instead of traditional bladed propellers, the Virginia class employs pump-jet propulsors by BAE Systems, initially made for the Royal Navy's Swiftsure-class submarines. These propulsors minimize cavitation risks and ensure quieter operations.