In ground combat, it is generally accepted that an attacker must own a 3:1 local advantage to achieve a breakthrough against a defended front. History has shown that rule of thumb to be reasonable at least in concept if not exact numerology. Indeed, the development of maneuver warfare is, partially, a recognition of that concept and an attempt to bypass its requirements.
Of course, this concept is applied to land warfare but does it offer any insights for naval warfare?
At the level of the individual sea battle, outcomes are usually determined by the maxim that the side that fires first, effectively, wins. Of course, there are other factors but the point is that sea battles seem not to adhere to the 3:1 rule. Why not? Well, the aspects of a land battle that grant the defender the advantage do not, for the most part, apply to naval battles. Bunkers, fortifications, overlapping fields of fire, concealment, etc. don’t exist at sea.
So, does that mean the 3:1 rule offers no insights for naval combat and that this will be one of ComNavOps shortest posts? I think you can anticipate the answer to that!
The 3:1 rule does, I think, offer some insights but not at the level of the individual sea battle. Instead, it applies to the broader and higher level of strategic naval operations, specifically the Anti-Access/Area Denial (A2/AD) scenario.
The attacker, attempting to penetrate the A2/AD zone, will have to face a defender able to utilize a limitless supply of assets (limitless in the sense that the defender’s entire air, naval, and land resources will be readily at hand) with multiple widely dispersed bases. In contrast, the attacker will be operating far from home bases and at the end of a long supply chain. While the attacker can bring all of its naval forces to bear, if it so chooses, its air forces will be only partially and sporadically present due to the likely ranges.
In addition, the defender will be able to utilize mines to attrite and, more importantly and more likely, direct the movement of the attacker along predictable paths to predictable locations.
The defender will be able to utilize land, sea, and air assets in a coordinated fashion while the attacker has only sea and air assets.
The defender will be able to obtain sensor information from mobile air and naval platforms, of course, but also land based radar and passive sensing stations. The attacker will be limited to airborne sensors and, to a limited extent, submarine sensors. Further, the attacker’s sensing platforms will be limited in persistence and vulnerable in operation. To be fair, the defender’s airborne sensing platforms will also be vulnerable but the attacker will have fewer assets available to prosecute those platforms. Last but not least, the defender will likely have installed underwater acoustic sensing systems (SOSUS-like).
The tyranny of range strongly favors the defender. Defending aircraft can operate for longer periods, achieve greater persistence, and generate higher sortie rates. Similarly, defending surface forces are closer to their bases for refueling, rearming, and repair.
The defender will be able to utilize land based anti-ship cruise (and ballistic?) missiles thereby achieving a large numerical superiority over the attacker’s missile reserves.
The defender can achieve a large degree of land based dispersion of assets which will greatly complicate the attacker’s targeting efforts and enhance the survivability of the defender’s assets. By comparison, the attacker’s weapons will be concentrated in a relatively few platforms and, probably, a relatively few groupings. While that concentration offers some defensive advantages (concentration of defensive firepower), it also offers a very tempting and exposed target for the defender.
Finally, the defender has the ability to repair combat damaged assets due to the proximity of manufacturing support and repair depots. The attacker will generally be unable to affect repairs and damaged assets will, to a large extent, be rendered “killed” for the duration. The days of slapping a patch on an aircraft or welding some plate on a ship are gone. The attacker, without access to depot level support, will be generally unable to make the complicated electronic, structural, and stealth repairs required to return assets to operational status in a relevant time frame.
The A2/AD scenario is not totally one-sided. The attacker retains the advantage of choice of time and, to a limited extent, place to initiate hostilities. This includes retaining the advantage of surprise to the extent that such can exist in this day of satellites, world wide communications, long range airborne sensors, etc. The attacker can also concentrate his available forces to the maximum extent possible against the specific chosen target. In contrast, the defender must defend a broader area until the attacker clearly indicates the specific target. A final advantage is that the attacker can retreat, if necessary, to fight another day if things aren’t going well. The defender has nowhere to go if things are going badly.
Considering the relative advantages and disadvantages of both sides in the A2/AD scenario, it seems obvious that the defender possesses some significant advantages compared to the defender. Reason would suggest that the attacker will require a significant numerical advantage in order to overcome the defender’s advantages. Whether that number is on the order of 3:1 or some other ratio is debatable but the concept seems valid. All else being equal, meaning approximately equal tech, training, tactics, and morale, the attacker will require a significant numerical advantage in order to overcome a defender’s A2/AD defenses.
Of course, if “all else” is not equal, the required numerical superiority of the attacker may be altered. If the defender is technologically deficient, poorly trained, poorly maintained, etc., the attacker’s required ratio may decrease. Still, as the Navy (and Air Force) contemplates penetrating
, China N. Korea, or ’s (and Iran ??) A2/AD zones, it would do well to carefully examine its current trend towards ever smaller fleet and aircraft numbers. We may find ourselves needing a 3:1 advantage and not having it. Russia