When commissioned, the main armament of the
Belknap class was a
5-inch/54-caliber Mk. 42 gun on the quarterdeck and a twin-rail
RIM-2 Terrier Mk 10 Mod 7 Guided Missile Launching System on the foredeck. The Mk 10 Mod 7 launchers in this class were modified compared to the others of the same type, with additional 20 missiles and the capability to launch
RUR-5 ASROC to eliminate need for a separate Mk 112 ASROC launcher. These were unofficially spoken of as Ter/AS (tear-ass) launchers. The class was also equipped with two single
3"/50 caliber guns for defence against sub-sonic aircraft. In the early 1980s, the Terrier missiles were replaced with RIM-67
Standard missiles; and during the
NTU program in the late 1980s and early 1990s the class had its Standard SM-1 system upgraded to utilize
SM-2ER Block II, the 3-inch guns were replaced with two 4 cell Harpoon surface-to-surface missile launchers, and two
Phalanx CIWS systems were installed. The derivative
USS Truxtun shared the weapons systems outfit of the
Belknap class, but was
nuclear-powered, larger and substantially unrelated in design (for example, many weapons systems in different locations, such as the aft-facing Mark 10 Mod 8 GMLS). Most information related to nuclear cruisers is still classified, but
Truxtun appears to be more a Belknap-like derivative of the nuclear cruiser
Bainbridge than the other way around. ==Ships in class==