Ohio class converted nuclear-powered guided-missile submarines are some of the Navy’s most valuable weapons. These four detailed machines began over 15 years ago with the decision to convert the four submarines from a SSBN class to what they are today, SSGNs. The Nuclear Posture Review determined that they only needed 14 out of the 18 subs they had for nuclear security, leading to the four oldest submarines being converted. New configurations allowed the subs to fire Tomahawks and lockout chambers were added. Recent reports indicated that they each carry around 100 Tomahawk missiles at all times.