Page "SSM-N-8 Regulus" Paragraph 14

The first launch from a submarine occurred in July 1953 from the deck of USS Tunny, a World War II fleet boat modified to carry Regulus.

Tunny and her sister boat USS Barbero were the United States's first nuclear deterrent patrol submarines.

They were joined in 1958 by two purpose built Regulus submarines, USS Grayback, USS Growler, and, later, by the nuclear powered USS Halibut.

So that no target would be left uncovered, four Regulus missiles had to be at sea at any given time.

Thus, Barbero and Tunny, each of which carried two Regulus missiles, patrolled simultaneously.

Growler and Grayback, with four missiles, or Halibut, with five, could patrol alone.

These five submarines made 40 Regulus strategic deterrent patrols between October 1959 and July 1964, when they were relieved by the George Washington class submarines carrying the Polaris missile system.

Barbero also earned the distinction of launching the only delivery of Missile Mail.