While the US Navy is converting four Trident missile submarines to carry 154 Tomahawk cruise missiles (seven per tube in 22 of the 24 tubes), this concept faces a problem. Cruise missiles are subsonic (they achieve their long range by using air-breathing engines) and cannot be employed against time critical targets, such as an attacking enemy tank brigade. To deal with such targets, the Navy is considering the idea of buying a missile from its ancient enemy, the Army. The Army Tactical Missile System does exactly what is needed (dealing with tank attacks by using a high-speed ballistic system to deliver dozens of anti-armor submunitions). There is a problem in that ATACMS is not designed for underwater launch, and converting it to this role would cost millions. So the current idea is to pack six ATACMS into a silo (replacing seven Tomahawks). The ATACMS would be sealed into a pair of three-missile floating packs (stacked on top of each other). When the submarine needs to employ ATACMS, it would release one of the packages which floats to the surface and is then triggered by remote control. The disadvantage is that all three missiles have to be used more or less at the same time, but this system could be deployed quickly and cheaply.--Stephen V Cole