KD Tunku Abdul Rahman (photo : Saorbats)
RMN’s Future Challenges
Once the RMN takes delivery of both Scorpenes (the Tunku ASbdul Rahman and Tun Abdul Razak), its undersea warfare specialists will be responsible for developing an offensive capability to search for, locate, identify, localize and prosecute those submarines classified as ‘hostile’ in line with its national security threat perceptions. For this to be achieved, a greater thrust would need to be given to acquisition of maritime domain awareness capabilities.
In order to enable the RMN fleet to operate freely in the probable operating areas of hostile SSKs, adequate force protection capabilities (such as shipborne ASW helicopters) will be required. Both submarine warfare and ASW are perhaps the most challenging and at the same time the most fascinating forms of naval warfare. A major challenge fazced by ASW forces is posed by the medium in which the targeted submarine operates. In sea water, which is saline and turbid, light and radio energy cannot be employed as a means of detection, since both suffer heavy attenuation.
The most efficient form of energy that can be employed underwater for ASW operations is ‘sound energy’. The vagaries of propagation of sound in sea water and the presence of a large number of non-submarine acoustical; signatures are a major challenge for both sonar researchers and practitioners of ASW. Remarkable advances have been made in both active and passive sonar suites and with advanced signals processing techniques, the detection and classification of submerged SSKs have greatly improved over the past decade.
The presence of a large number of non-submarine acoustical echoes, however, still poses a major challenge. Synergy between technologies, tactics and sonar operating skills is the only answer to overcome this shortcoming. Principal surface combatants and SSKs engaged in ASW would have to be made stealthier and their sonars made capable of being operated from high-speed platforms.
Since the medium in which a submarine operates plays such an important role, a thorough knowledge of the hydrology of the areas of operation is sine qua non. A digitised atlas containing the parameters that impact on the propagation of sound would have to be drawn up and updated periodically. The process of data collection being both sensitive and laborious, much of this activity would have to be undertaken discreetly.
Whilst ultra-low frequency sonar suites have proven to be dependable against submarines operating in open oceans, a more complex challenge comes from submarines that tend to operate in littoral waters (with depths of less than 200 metres), where ambient noise is higher. Also, the sonar’s performance gets degraded at such depths due to environmental and hydrological reasons.
MBDA's SM-39 Exocet : range 50 km (image : MBDA)
The solution lies in procuring new-generation ultra-low frequency sonars that can extract weak and confusing acoustic signals through advanced processing algorithms and new design architectures. Shallow water performance of ASW torpedoes and other weapons used for undersea warfare will also need to be improved. The answer, perhaps, lies in sonars with wide bandwidths and high gain, operating on much lower frequencies.
Honing of operator skills and adopting electronic decision-making aids will enable much improved situational awareness in the context of rapidly-changing tactical scenarios, where the best course of action may not be obvious. It may be argued that shallow waters also degrade a submarine’s sonar performance. This is true. However, a submarine can optimize the conditions by operating at most favourable depths or by entering ‘sound channels’. ASW forces can counter this by deploying variable depth sonar arrays. Another useful tactic will be to equip SSKs with such thin-line towed-array sonars and employ them in the ‘hunter-killer’ role.
In order to optimise available ASW efforts and to counter large numbers of opposing submarines, coordinated ASW operations would need to be undertaken. The coordinated ASW operations will have to include principal surface combatants, submarines, UAVs and maritime surveillance/ASW aircraft (both fixed-wing aircraft and helicopters), both shipborne and land-based.
Black Shark torpedoes : range 50 km (photo : Finmeccanica)
Considering the sheer magnitude of the ASW task, the RMN would need to considerably augment its force levels and embrace innovative tactical measures. A shift from platform-centric to network-centric ASW will lead to greater coordination and synergy. This will involve the networking of command, control, communications, intelligence, surveillance, target acquisition and reconnaissance assets, for developing a common synthesised digital situational picture of the maritime battlespace, thereby facilitating real-time targetting, reduced sensor-to-shooter time lags, and precision-guided ASW attacks. And since information warfare is an important component of any military force modernisation programme, the RMN would need to adopt measures to maintain complete network security.
Finally, the strategic geography of Malaysia is ideally suited for laying a network of seabed-based listening sensors using low-frequency analysis and ranging (LOFAR) techniques., which is a powerful tool for increasing the signal-to-noise ratio. A deployed LOFAR barrier and maritime surveillance/ASW aircraft can effectively combine to locate, identify, localise and prosecute a targeted submarine. This combination is also well-suited for strategic ASW roles in a hostile submarine’s area of operations.
To effectively utilise LOFAR-based techniques for hunting hostile submarines using passive-array sonars, it is important to create and maintain a ‘threat library’ of targetted submarine signatures, which are a unique blend of narrow and broadband acoustic signatures at varying levels for each class of submarines and more often for each individual submarine . Prior knowledge of such signatures is fundamental to LOFAR strategy and is applicable to all LOFAR devices, whether laid on the seabed or arrays deployed from principal surface combatants, submarines or aircraft. Submarihnjes are eminently qualified for collecting such data with respect to opposing submarines. Seabed arrays could also be used for intelligence-gathering.
Secrecy of location and capability of a deployed ASW barrier is of paramount importance for its success. To operate freely and unhindered in a submarine’s probable area of operations, ASW forces will have to resort to dispersal, signature control, cooperative deception, and mobility in addition to adoption of material countermeasures. Both ‘soft kill’ and ‘hard kill’ measures would need to be adopted. Additionally, the deployed surface warfare and undersea warfare forces will have to be EMP-hardened.