Why Australia’s nuclear submarines should have vertical missile launchers

China’s growing power and assertiveness have been significant drivers behind developments in Australian defense policy in recent years. The previous government’s strategic update stated that the military needed the ability to ‘shape’ Australia’s strategic environment, ‘deter’ threats to Australian interests and ‘respond’ with credible military force. Since then, a bipartisan commitment to the acquisition of nuclear-powered submarines has emerged and the government under Prime Minister Anthony Albanese has begun its own defense strategic review. That review and the report of the nuclear submarine task force will be available in the first quarter of this year.

One problem confronting the independent leaders of the strategic review and which the nuclear submarine task force must consider is that the Australian Defense Force lacks the lethality to shape the strategic environment or deter a great power.

Of particular concern are the yet-to-be-delivered Hobart-class destroyers and Jagter-class frigates. These ships will be the Navy’s primary surface combatants for the next 30 years, but they have very few vertical launch cells compared to their American and Chinese counterparts. The problem is that a future conflict is expected to be a ‘missile-to-missile game’. Some analysts doubt the effectiveness of surface fighters altogether.

In a previous post I argued that the best way to deter aggression, and win a war if necessary, is to work with our allies to maximize the forces that limit an aggressor’s ability to wage war can neutralize. I proposed equipping the Collins-class submarines with Tomahawk missiles to rapidly and cost-effectively improve the ADF’s offensive power.

Missile-armed submarines are the best way to deter an aggressor because of their offensive range and inherent stealth. Nuclear submarines add mobility and endurance to the mix. For this reason, Australia’s new submarines must be – essentially – guided-missile submarines, or SSGNs. SSGNs would shape Australia’s strategic environment and deter threats to Australian interests more effectively than a fleet of traditional nuclear-powered attack submarines (SSNs) because they would act as a powerful ‘fleet in essence’.

The concept of a fleet in being originated in the naval wars of the 18th century. The original idea was that one could prevent invasion even if one’s fleet was smaller than the enemy’s by avoiding its destruction in battle and thereby maintaining the threat it posed to expeditionary forces. In modern naval strategy, the concept refers to the extreme uncertainty created by a powerful and mobile force when its whereabouts are unknown. Because the force can attack at any point or time without warning, an opponent is unable to concentrate its defenses. It is a significant deterrent to initiating conflict and, in the event of war, forces the adversary to devote limited resources to defending valuable assets and thereby limits the scope of its offensive operations.

The campaign against German territories in the Pacific during World War I provides an example. German Admiral Maximilian von Spee curtailed Australia’s attempts to capture German-held islands such as Rabaul, Angaur, Nauru and Yap. Spee’s mere presence in the Western Pacific required Australia’s military expeditions to be escorted with sufficient forces to counter his squadron, and the only British Empire warship in the Pacific up to the task was the battlecruiser HMAS Australia. The Australia could not be everywhere at once, so convoys had to proceed one at a time rather than simultaneously. Some even had to be abandoned.

In today’s context, a powerful fleet of submarines means that an adversary will have to guard its assets and expeditions with significant anti-submarine forces. These forces are limited, so the scope of the adversary’s offensive operations will be suppressed. This would allow Australia and its allies to concentrate their other forces for maximum effect.

The strategic influence that a fleet essentially wields is directly proportional to its strength or lethality. In other words, the more lethal his weapon systems are, the more they will affect his opponent’s calculations. A fleet of SSGNs would essentially constitute the ultimate fleet, with mobility, endurance, stealth and maximum conventional lethality. Despite being classified as an SSN, the US Block V Virginia class will essentially be a missile submarine. The design was augmented to carry 65 weapons and fire them in a rapid burst from vertical launch cells. The British Astute class SSN carries 38 weapons and can only launch them in bursts of six from its torpedo tubes.

The Americans plan to arm the new Virginias with Block V Tomahawks. These weapons have a range of approximately 1,600 kilometers and, in addition to the land strike role for which Tomahawks are known, have a new anti-ship capability. Hypersonic missiles are said to be deployed aboard Block V Virginias from 2028, increasing their lethality even further. A single Virginia-class sub would be capable of dropping land targets or an enemy task force from great range with dozens of missiles. A ‘wolfpack’ of Block V Virginias would likely pose an insurmountable threat to a surface task force.

Beyond acquiring nuclear weapons, building a fleet of SSGNs is the most effective way to shape Australia’s strategic environment and deter a great power. A fleet of SSGNs would make it extremely difficult to exert military pressure against Australia. To do so, an adversary would have to accept extraordinary risks to its own forces and infrastructure.