How early could naval VLS have appeared?

What is the earliest period in which a VLS-style naval system could have appeared?

Work began in the 1960s, but the difficulty of turning missiles immediately after launch and controlling a useful salvo delayed practical systems.

Work on vertical launch concepts was under way in the 1960s. Vertical mine tubes and torpedoes with gyroscopic course changes supplied parts of the conceptual foundation. The difficult step was making a missile orient itself immediately after a vertical launch. Computing and control capacity also had to support enough simultaneous missiles for VLS to outperform an arm launcher.