"Root & Branch review of defence spending announced"

[Modern Elmo]

The SLIRBM will have a maximum diameter of 32.5 inches

First Virginia Class Payload Tube Increases Force's Versatility
Story Number: NNS090521-02

5/21/2009

From Program Executive Office, Submarines Public Affairs
WASHINGTON (NNS) -- Program Executive Office Submarines' Virginia-class Program Office marked a substantial milestone May 15 with the delivery of the first Virginia payload tube (VPT).

Built by General Dynamics Electric Boat (GDEB), the VPT arrived at GDEB's Virginia-class shipbuilding partner Northrop Grumman Shipbuilding's Newport News (NGSB-NN) facility for inclusion in Pre-Commissioning Unit North Dakota's (SSN 784) bow. As part of a teaming arrangement, NGSB-NN builds all Virginia-class bows while GDEB constructs all of the VPTs.

As the lead submarine being built under the third, or Block III contract, North Dakota will be the first Virginia-class submarine equipped with VPTs.
Unlike the first 10 Virginia-class submarines that housed 12 Tomahawk cruise missiles in individual Vertical Launch System (VLS) tubes, all Virginia-class submarines beginning with North Dakota will utilize two, 87.5-inch diameter, 35-plus ton tubes to house and launch the same number of missiles.

http://www.navy.mil/search/print.asp?story_id=45461&VIRIN=58533&imagetype=1&page=1

32.5", 87.5", hmmm.