Helpful Lessons from an Unhelpful Source

Land-Based Maritime Strike in the Red Sea Crisis

At the base of the Gulf of Suez, a tiny non-state actor is demonstrating how area denial tactics can create a strategic dilemma for larger and more capable nations. Since October 2023, the Houthi movement has used a combination of unconventional naval and land-based maritime strike (LBMS) attacks to restrict passage through the Red Sea. Though individual attacks have been ineffective, the broader threat has been impactful, reducing shipping throughput by 42%.^[1] More pressingly, air strikes against the Houthi have not stopped the attacks, raising concerns about the potential need for an indefinite commitment by the US and allies to secure the passage.    

Land-based strikes against modern ships are rare, and a sustained campaign of attacks is even rarer. Though occurring in a different operating environment to the Indo-Pacific, the Red Sea Crisis provides a unique opportunity for the Army to infer valuable lessons for its own future LBMS capability.

The Attraction of Land-Based Maritime Strike

As missile technology progresses, the resilience offered by LBMS becomes more appealing. The increased range and capability of missiles means fixed airbases and infrastructure are increasingly vulnerable to strikes early in any conflict.^[2] Unlike airbases, LBMS offers the opportunity to disperse launchers over a large area and conceal them amongst complex terrain, confounding pre-conflict surveillance.^[3] Once conflict commences, these launchers can move between firing sites, demanding even more resources to target. Even if targeting is successful, losing a single LBMS platform will not neutralise the other launchers. Meanwhile, increasingly federated networks provide targeting data from a wider variety of sources, reducing the criticality of dedicated target acquisition systems.^[4] Notably, this data is not only from military sources, as the Houthi’s have been using open-source information from ships’ automatic identification systems to locate ship, and discriminate which are operated by countries with associations to Israel.^[5] These features impose a daunting targeting challenge on any forces seeking to establish sea control, redirect resources, and slow operational tempo.^[6] 

The resilience of LBMS networks is currently being demonstrated in Yemen. The  Houthi rebels have had an extensive history of operating under air threat, having been under frequent air attack since the Yemen Civil War commenced in 2014.^[7] It is perhaps unsurprising then that while the current coalition air campaign to target the Houthi LBMS network has reported some ‘tactical successes,’ it has not actually stopped the Houthi’s from continuing their attacks.^[8][9] Added to this, it is uncertain how effective airstrikes will be in the long-term – the initial size of the Houthi missile stockpile is an unknown, as is the frequency and quantity of Iranian resupply of new systems to offset any losses^[10][11]. Even if the air campaign intensifies, without a ground threat the Houthi may choose to conceal their LBMS platforms and wait out any intervention. In either case, their network has demonstrated resilience to air attack, raising concerns about how long the current military commitment might last. Indeed, some observers question whether the Red Sea Crisis can ever be resolved.^[12]   

It is interesting to note the Houthi attacks have been more dissuading than destructive. From at least 40 attacks, only one civilian vessel has been sunk .^[13][14]. Naval ships have also been attacked, but none have even been hit. While this is encouraging data about the effectiveness of modern anti-missile systems, ensuring civilian ships have the same protections requires a continuous naval presence in the passage. In this respect, the Red Sea geography hinders the Houthi, as the area where attacks are likely to occur can be predicted and proactively patrolled. Nonetheless, even if the damage caused has been limited, the Houthi have used LBMS to create a strategic dilemma for the US and allies, resulting in an indefinite commitment to a naval operation to secure the Red Sea.^[15] 

Potential Lessons for Army

Under Land 4100 Phase 2, the Army will acquire an unprecedented-for-Australia LBMS capability,^[16] but it is not breaking new ground. Within the Indo-Pacific, LBMS has been widely discussed with parallels been drawn between events in the Red Sea and the significance of the Malacca Strait to Chinese oil supply. Specifically, the United States sees an opportunity to use China’s vulnerabilities in the strait as a way to contain it under the Pacific Deterrence Initiative^[17]. While any denial effort within the Malacca Strait – or indeed any part of the Pacific – could be described as an ‘anti-access and area denial’ tactic, the two parts of the phrase imply different outcomes, and so their meaning should be considered separately.^[18]

The first approach is anti-access, where absolute access to an objective is prevented. The Red Sea crisis demonstrates the challenge of achieving anti-access effects, even when the access being prevented is through strait a mere 32 kilometres wide.^[19] In this regard it is notable that, despite the Houthi attacks occurring within ideal geography, commercial shipping can still transit through the Red Sea, and every attack on a naval ship has been defeated – which is hardly denying passage. The prospect of achieving anti-access effects across a wider area such as in the Indo-Pacific then comes into doubt, as vessels do not need to transit so close to shore and have multiple routes to use. While these observations do not invalidate the concept of denying access to a specific objective (i.e. an island or a port), they add evidence against arguments that this tactic can be scaled up to provide containment across a large area.^[20]

The second approach is area denial, where the risk to an opponent of operating in an area is elevated, but access is not outright prevented. The confounding resistance of Houthi LBMS systems to air attack has strengthened the viability of this concept for in an Indo-Pacific scenario. To effectively neutralise a widely dispersed LBMS network would require an immense commitment of intelligence and strike assets. Even then, the growing maturity of automated LBMS, such as the US Autonomous Multi-Domain Launcher, ^[21] increases the persistence of launchers even in high-threat environments. While these operations are not decisive in their own right, they force their target to commit naval forces to provide protection over a very large area, against a threat which can always be present, but which is not necessarily always active. Consequently, the adversary’s naval power is inevitably diffused to provide protection everywhere, leaving it less able to concentrate elsewhere for decisive action. The overall goal of an area denial approach is not to create an acute effect but instead to create a chronic threat for as long a duration, and as wide an area, as possible – an approach being demonstrated successfully in the Red Sea^[22].

In Closing

Given the vast differences between the Houthi rebels and the ADF, there may initially seem to be little for the Australian Army to learn about its newest capabilities from such a non-state actor. Nevertheless, such lessons do exist. While individual attacks by the Houthi have been ineffectual, their capacity to sustain an LBMS threat despite substantial air attacks has imposed a substantial dilemma on a larger and more capable coalition force. Conceptually, there are many similarities to the ADF’s aspirations in the Indo-Pacific to employ capabilities that impose an outsized dilemma. So, as surprising as it may first seem, the Army would be well placed to watch attentively the Houthi’s actions and unfolding events in the Red Sea. 

Endnotes