What navies could use if the Oerlikon 20 mm disappeared

What could navies use if the Oerlikon 20 mm cannon were unavailable?

Possible substitutes include naval Hispano cannon and Vickers heavy machine guns, or a British mix using pom-poms at close range and Bofors farther out.

A naval Hispano cannon or the Vickers heavy machine-gun mounting could fill part of the gap left by an unavailable Oerlikon. Another suggested British arrangement uses two different 40 mm weapons. The pom-pom takes the close-range role otherwise assigned to Oerlikon, while Bofors covers the longer-range role. These are possible alternatives in the hypothetical, without a detailed assessment of their comparative performance.