OPTIMIZING NAVAL FORCE COMPOSITION: PERSPECTIVES FROM THE HUGHES SALVO MODEL

Indian Naval Despatch, Vol. 4 No. 1 (Spring 2023) “Small May be More Lethal - Indian Naval Force Structuring Considerations” by Lt Cdr Rohan Kulkarni and Indian Naval Despatch, Vol. 4 No. 2 (Monsoon 2023). “Hughes Salvo Model Broadside” by Lt Cdr Dhruv Panwar.

In his Both Watches response to my article ‘Small may be more lethal- Indian Naval Force Structuring Considerations’ published in Spring 2023 edition of Indian Naval Despatch, Cdr Dhruv Panwar as opined, and rightly so, that the choice between induction of smaller warships in place of larger ships is always a difficult one. In his article, he also provides a few arguments leaning towards larger platforms, concluding that a mixed bag would best aid the Indian Navy (IN) in performing its roles effectively. While the author has touched upon a few facets of the ‘Hughes Salvo Model,’ this article encapsulates the critical nuances and insights offered by the model, pertinent to countering adversaries in our areas of interest.

In ‘Hughes Salvo Broadside,’ he suggests that a destroyer with a higher weapon-carrying capacity, resulting in greater offensive, defensive and staying power, is better suited to challenge a Renhai or Luyang III class destroyer of the PLAN, rather than a greater number of frigates with lesser capability, due to numerous factors such as combat capability, command and control, and so on. Let us examine this proposition with the help of the salvo equations.

Wayne Hughes used a term called the fractional exchange ratio (FER), which compares the relative effectiveness of the two sides involved in the conflict and is expressed as:¹

When FER > 1, B will lose more forces than A, and when FER < 1, B will have more forces remaining at the end of the battle.

(a) Situation A. In this situation, we consider two forces with one destroyer each and with equal capabilities.

Using the formula for FER expressed above, we see that FER = 1, that is, there is parity.

(b) Situation B. In this situation, we consider the Blue Force with two ships (frigates), but with less capability than the Red Force (a frigate compared with a destroyer). The capability of the Red Force remains the same, except that it will now have to fire a higher number of missiles to cater for two ships.

Now we see that,

FER < 1 implies that the Red Force will lose its ship at the end of the engagement. It will be able to achieve parity only if its staying power and defensive power are twice that of the Blue Force, thereby considerably straining its resources. As is also evident from the example above, though a ship in the Blue Force has less capability than its adversary, it was able to tilt the outcome in its favour due to its numerical advantage. The paramount takeaway from the equations is that, in conflict, numerical superiority is usually the governing force attribute.

The Hughes salvo model enables a quantitative approach to determining the offensive and defensive capabilities of a force. However, there are other key elements consisting of a mix of quantitative and qualitative factors of warfare, which the equations allude to and which often slip below the radar.

(c) Scouting Effectiveness. There is a need to enhance our coastal and open-ocean surveillance capabilities in order to gain accurate information about the adversary’s movements at all times. Augmenting the coastal radar chain through artificial intelligence, investing in over-the-horizon (OTH) radars, and using aerostats offer plausible solutions. More importantly, giving adequate propulsion to our satellite-based surveillance programmes would facilitate an increased surveillance swath, enabling a greater footprint and ensuring that the adversary is wary of our presence, thereby increasing his circumspection. Additionally, there is a need to continue our efforts to counter adversaries’ surveillance capabilities. The equations tell us that, to achieve parity with a numerically superior force, we need to degrade its scouting effectiveness by a factor equal to the inverse square of the force’s numerical superiority. Discernibly, smaller platforms offer significant solutions to overall signature management, thereby increasing the surveillance effort by the adversary.

(d) Staying Power. It is worth noting that staying power is distinctively independent of all other factors, such as offensive power, scouting, training and defensive power. It may be recalled from the paper that staying power is about the “number of hits a ship can sustain before it is rendered out of action.” Therefore, even though a ship may have significantly large offensive and defensive capability, and even greater endurance, a low overall staying power, coupled with an inefficient damage-control organisation, would lead to a debacle, as was seen in the case of the Moskva. She was 186 m long and carried a lethal weapon load; however, it took only two missile hits for her to be damaged and sink thereafter, reiterating that higher defensive or offensive power cannot truly compensate for a feeling — actually, a misconception — that smaller ships invariably have lower staying power.² Thus, efficient design and good shipbuilding standards also have to be matched by an alert watch and good training as well as leadership. In terms of endurance, smaller ships could have a disadvantage. This was truer for the Indian Navy of earlier decades but is not quite so now. In any case, many frigates and corvettes are as capable of underway replenishment as larger ships.

(e) Coastal Batteries. Historically, the outcome of naval battles was dependent on the capabilities of forces — air, surface and sub-surface — that could be committed in that particular engagement. However, forces based on land, equipped with long-range anti-ship missiles, might now play even more vital roles in influencing the conflict at sea. In recent years, the PLA has developed a robust long-range land-based anti-ship missile arsenal and has various versions of the Dong Feng (DF) missiles at its disposal.³ Therefore, the capabilities of land-based forces equipped with anti-ship missiles need to be factored into others’ planning considerations as well as in one’s own arsenal. The sinking of the Moskva, without the direct involvement of Ukrainian naval assets at sea, illustrates this. A further look into the equations shows the advantages of a potent land-based anti-ship strike capability. The suggestion is by no means novel to the Indian Navy, because shore-based anti-ship missile batteries were introduced into the arsenal decades ago. However, it is prudent to modernise and enhance such capabilities to have a compelling effect on the adversary, should it come to that.

Cost and Time Implications

We have seen that, despite the absence of an open conflict, the tasking of our forces has increased considerably. It is also necessary to transition from constabulary roles to higher-end combat at short notice; therefore, among other things, numbers continue to matter. Moreover, as is evident from analysing the equations, a concrete method to counter the PLAN in the Indian Ocean Region is to have numerical superiority when and where it matters. The need of the hour is, therefore, to have sufficient platforms to meet all the objectives set forth, and to have them in the shortest time possible, while maximising the possibility of improving the numbers, ranges and lethality of the ordnance carried on each platform in every medium.

Historical comparisons of shipbuilding timelines indicate that larger platforms take longer to build. They have higher shipbuilding and life-cycle costs compared with smaller platforms. For example, open-source reports indicate that each Visakhapatnam-class destroyer is being built at a cost of around Rs 9,000 crore per vessel,⁴ whereas each ship of the Nilgiri class would cost around Rs 4,000 crore.⁵ The example of the salvo equations shown previously illustrates that two smaller platforms with lesser capability are likely to fare better than a single, all-encompassing bigger platform.

Larger platforms are vital, and it is not my case not to have them. However, investing more in building smaller platforms is the recommended way ahead, in our plans as well as on the slipways, to fulfil our defined roles. Finally, adopting a multi-pronged approach by investing in uncrewed assets, which offer distinct advantages towards deployability and effectiveness in naval operations, would also be part of the future thrust.