Neptunes, the MOSKVA, and How Not to Sink a Cruiser.
By Anthony Cowden
April 19, 2022
The United States is now confirming that the Ukrainians did indeed fire Neptune anti-ship cruise missiles (ASCMs) which led to the sinking of the Russian cruiser MOSKVA, flagship of the Russian Black Sea Fleet.
[i]
A careful analysis of the engagement would indicate that the Ukrainians did not shoot enough missiles and that the defensive capability of the MOSKVA was flawed. The purpose of this article is to lay out that analysis.
In conducting this analysis, we will employ the Salvo Equations, developed by the late Captain Wayne Hughes and discussed in detail in
Fighting the Fleet: Operational Art and Modern Fleet Combat.
[ii] With the Salvo Equations, Captain Hughes…
…showed how modern naval combat follows a salvo model: opponents apply a pulse of combat power to each other in an instantaneous salvo exchange. A salvo exchange is an interaction of offensive combat power (e.g., mines, torpedoes, bombs, or missiles) and defensive combat power (e.g., surface-to-air missiles [SAMs], jamming, chaff, decoys). Combat power remaining from these interactions is applied against a target’s staying power (the number of hits of a particular weapon that a target can withstand and still be useful for combat purposes).[iii]
The Salvo Equations are presented here for reference and are discussed in great detail in Chapter 1 and Appendix A of Fighting the Fleet:
where:
In a normal usage of the Salvo Equations, we would run the equations for both sides in the engagement, representing two (or more) ships firing ASCMs at each other. In this case, we only need to run the equations for the MOSKVA since the Ukrainians fired from a platform that cannot be sunk (i.e., the land).
Using the Salvo Equations is fairly straightforward. Parameters and assumptions associated with this analysis include the following:
[iv]- All ship and weapon system characteristics were derived from UNCLASSIFIED sources (i.e., Wikipedia).
- “Force A” is represented by the MOSKVA[v]
- MOSKVA is equipped with the SA-N-6 surface-to-air missile, which has the ability to shoot down ASCMs.[vi]
- MOSKVA is equipped with AK-630M close-in weapon system (CIWS), which has the ability to shoot down ASCMs.[vii]
- MOSKVA is equipped with the Rum Tub and Side Globe electronic warfare (EW) system and two PK-2 DL chaff and flare launchers, all of which are assumed to have some capability to defeat ASCMs.
- “Force B” is represented by the two Ukrainian Neptune ASCMs.[viii]
- All ASCMs are assumed to be "well-aimed".
- There were no other vessels in the target areas, such that ASCMs did not accidentally strike other vessels instead of the intended target.
- In terms of a3 (the number of well-aimed missiles that could be destroyed by the MOSKVA):
- The MOSKVA’s Surface-to-Air Missile (SAM) system could defeat two (2) incoming ASCMs.
- The MOSKVA’s passive and non-kinetic defensive systems (decoys, jamming, etc.) could defeat two (2) incoming ASCMs.
- The MOSKVA’s CIWS could defeat two (2) incoming ASCMs.
- It takes five (5) Neptune ASCMs to put the MOSKVA out of action (a1) (although it could take substantially fewer missiles to damage the MOSKVA).
This last assumption is based on the Cube Root Rule and requires further explanation. In research conducted on steel-hulled ships in combat,…
…the amount of thousand-pound bomb equivalents (TPBEs) of high explosive required to put a ship out of action, on average, was roughly proportional to the cube root of one-thousandth of a ship’s tonnage.[ix]
According to Wikipedia, the warhead on the Neptune ASCM weighs 150 kilograms or 330 lbs. Assuming that 330 lbs of modern explosive is equivalent to 500 lbs of high explosive, and given that the Cube Root rule suggest that it would take 2,320 lbs of HE to put Moskva out of action
[x], then it should take 4.64 Neptune ASCMs to put MOSKVA out of action. Rounding up – after all, one can't shoot .64 missiles - it should require five (5) Neptune ASCMs to ensure MOSKVA is put out of action.
[xi]
Based on the assumptions outlined above, the Salvo Equation for this engagement between two Ukrainian Neptune ASCMs and the Russian cruiser MOSKVA can be run ahead of time to analyze the engagement. It should be noted here that the Salvo Equations are not predictive in nature – one should not employ them in an attempt to predict what will happen – they are best used to understand the nature of a missile exchange and the considerations involved, not to predict combat outcomes. In any event, this running of the salvo equation is depicted in
Figure 1:
Figure 1. Engagement Salvo Equation Results
In this case, we assumed that the Ukrainians fired 11 ASCMs to ensure they would overcome the expected ability of the MOSKVA to defeat six (6) incoming ASCMs. The result indicates that the MOSKVA should be put out of action, but with no margin for error: if the MOSKVA destroyed or defeated more missiles, or if some missiles missed or acquired another target, they would not inflict the expected damage to the MOSKVA, so in reality, the Ukrainians might want to fire more than 11 missiles.
What we believe actually happened, however, is that the Ukrainians fired two (2) Neptune ASCMs, the MOSKVA did not destroy or defeat either of them, both missiles hit the MOSKVA, and the MOSKVA suffered severe damage that eventually led it to sink.[xii] The actual Salvo Equation, then is depicted in
Figure 2:
Figure 2. Salvo Equation Results for the Actual Engagement
This analysis shows that the MOSKVA, while likely to be severely damaged, should not have been sunk. And, in fact, MOSKVA did not sink immediately. However, it does suggest that possibly MOSKVA's damage control (DC) efforts to combat the sustained damage were not all they could have been. However, ship design plays a significant part in the ability of a given ship to sustain damage. For example, MOSKVA's main armament, 16 large P-500 Bazalt or P-1000 Vulcan ASCMs, were housed in 16 large missile tubes, taking up much of the exposed deck space of the MOSKVA. Should a missile hit one or more of these launchers, it is presumed that it might cause a significant secondary fire or explosion, causing even more damage than an incoming missile might cause.
In summary, then – and again, the reader is urged to take the Salvo Equations for a spin using their own assumptions – it is fair to say that the Ukrainians probably should have shot more missiles, the MOSKVA should have destroyed or defeated more missiles, and that MOSKVA’s DC efforts or ship design to sustain damage could have used improvement.
Anthony Cowden is the Managing Director of Stari Consulting Services and co-author of Fighting the Fleet: Operational Art and Modern Fleet Combat, all royalties for which go to the Navy/Marine Corps Relief Society.
Notes:
[i] Current open-source reporting does not confirm how many missiles were fired, how many missiles might have been destroyed or decoyed by the MOSKVA, or how many missiles hit the MOSKVA, but we will assume the answers are two (2) missiles fired, none defeated/destroyed, and two (2) hit.
[ii] The assumptions presented here are just that – assumptions. The reader is invited – nay, urged! - to come up with their own assumptions and take the Salvo Equations for a spin themselves!
[iii] https://en.wikipedia.org/wiki/Russian_cruiser_Moskva
[iv] https://en.wikipedia.org/wiki/S-300_...S-300F_(SA-N-6)
[v] https://en.wikipedia.org/wiki/AK-630
[vi] https://en.wikipedia.org/wiki/R-360_Neptune
[vii] https://www.usni.org/press/books/fighting-fleet, p. 23
[viii] MOSKVA displaced 12,490 tons, a thousandth of which is 12.49, the cube root of which is 2.3201.
[ix] Of course, “stuff” happens in combat, and as we have seen, it is possible that significantly fewer ASCMs could put MOSKVA out of action. That is part of "combat entropy," also discussed in Fighting the Fleet, Chapter 1.
[x] https://www.wsj.com/articles/russian...ms-11650043527
[xi] Cares, Jeffrey R. and Anthony Cowden, Fighting the Fleet: Operational Art and Modern Fleet Combat. Annapolis: US Naval Institute, 2021.
https://www.usni.org/press/books/fighting-fleet
[xii] https://www.usni.org/press/books/fighting-fleet, p. 16
