The new CMC/AL assemblies are slated for production in blocks of 4 tubes, allowing each partner to tailor the total number of missile tubes to its final submarine design.
Current American Ohio Class SSBNs have 24 tubes, but SSBN-X currently plans to reduce that to 16 tubes. Britain’s current Vanguard Class has 16 tubes, but the number of tubes in its Successor Class hasn’t been set yet.
While CMC will define key constraints for America and Britain, it may also create opportunities.
One is built-in: commonality between their respective launch systems makes it easier to share changes and advances.
The other opportunity is about flexibility. There is no question that the future Common Missile Compartment will be built around the nuclear deterrence mission as its primary focus. That is unlikely to be its sole use, however, and it would not be surprising if some of those other potential uses ended up influencing the CMC’s design.
Converted Ohio class SSGNs, for instance, have already replaced nuclear missiles with American special forces, land attack missiles, and UAVs. In a similar and related vein, the Virginia Class Block III fast attack submarine replaced their 12 vertical-launch cruise missile tubes with 2 Common Weapon Launcher (CWL) “six-shooters” derived from the SSGNs’ converted missile tubes. The size of those CWLs allows Virginia Class Block III submarines to launch cruise missiles, UAVs, UUVs, and more from these same tubes.
Nuclear missile submarines are a nation’s most strategic assets, because they are its most secure and certain deterrence option. One does not commit them casually, to any purpose. As key trends like cheaper sensors and the Robotic Revolution grind onward, however, the next 40 years will see big changes in the underwater environment. SSBNs will need the flexibility to adapt and leverage these changes if they intend to survive. For the USA and Britain, the CMC needs to be part of that adaptation.