The Hunt For Red October posited the existence of massive Soviet submarines lurking in the ocean, but it was based on fact. The Typhoon-class subs are the largest military submarines ever built, clocking in at a staggering 515 feet long. Each of the six Typhoon subs built carried a payload of 20 ballistic nuclear missiles and was capable of staying submerged for three solid months at a time. A crew of 160 sailors was required to operate them. Amazingly enough, for a vehicle of its size the Typhoon was remarkably stealthy, thanks to a five-layer hull of sound-dampening plates.