The W58 was an American thermonuclear warhead used on the Polaris A-3

UGM-27 Polaris

The Polaris missile was a two-stage solid-fuel nuclear-armed submarine-launched ballistic missile built during the Cold War by Lockheed Corporation of California for the United States Navy....

 submarine launched ballistic missile. Three W58 warheads were fitted as multiple warheads on each Polaris A-3 missile.

The W58 was 15.6 inches (39.6 cm) in diameter and 40.3 inches (102.4 cm) long, with a basic weight for the warhead of 257 pounds (116.6 kg). The yield was 200 kilotons.

The W58 design entered service in 1964 and the last models were retired in 1982 with the last Polaris missiles.

Researcher Chuck Hansen claims based on his US nuclear program research that the W55

W55

The W55 was an American thermonuclear warhead used as the warhead for the SUBROC antisubmarine rocket system. The W55 was designed in the early-1960s, and produced from 1964 to 1968. The last units were retired from service in 1990. A total of 285 W55 weapons were produced.The W55 had a yield...

 and W58 warheads shared a common Primary or fission first stage, and that this design was nicknamed the Kinglet primary

Kinglet primary

Kinglet was a boosted fission primary used in two designs of American thermonuclear weapons, the W55 and the W58; and was also adapted by the British as a super-hardened primary known as Harriet used in the Chevaline improvements to the British Polaris A-3TK missile.Primary is the technical term...

by Hansen in 2001.

External links

• Allbombs.html list of all US nuclear warheads at nuclearweaponarchive.org