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The Block III submarines will be the first of the class to be fitted with the Virginia Payload Tubes (VPT), a development of the modified former ballistic missile launch tubes in the Ohio-class converted cruise missile subs. Two VPTs in the bow of each of the new submarines will replace 12 vertical launch tubes used for Tomahawk cruise missiles in previous submarines. The 92-inch-wide VPTs each can hold six cruise missiles.

U.S. Navy Orders 8 New Subs - Defense News


Block III: The Changes

The most obvious change is the switch from 12 vertical launch tubes, to 12 missiles in 2 tubes that use technology from the Ohio Class special forces/ strike SSGN program. The Virginia’s hull has a smaller cross-section than the converted ballistic missile SSGNs, so the “6-shooters” will be shorter and a bit wider. Nevertheless, they will share a great deal of common technology, allowing innovations on either platform to be incorporated into the other submarine class during major maintenance milestones. Net savings are about $8 million to program baseline costs.

8 more USN Virginia class submarines? (Block III, revised bow)

Further, replacing 12 vertical launch tubes with two 92-inch VPTs not only reduces construction and lifecycle costs, but also significantly expands their ability to accept future payloads.

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"The VPTs provide commonality with the SSGN tubes, so payloads developed for one can go into the other," said Rear Adm. William Hilarides, Program Executive Officer, Submarines. "This affords the submarine force incredible flexibility and versatility to the far future."

First Virginia Class Payload Tube Increases Force's Versatility