Defending Island Chains: A Fixed Defence Model

Given the state of territorial conflicts in East Asia, defence analysts and planners are looking at how island archipelagos may be defended on an ongoing basis. Here is one possible model.

We assume a group of islands under threat of intimidation or occupation by sea and air, which its government is willing to defend by force. We also assume that risk of conflict is long-term and persistent, and that a solution that reduces the need for constant naval and air patrols is sought, or, alternatively, that the position at sea and in the air is so tenuous that any means to prolong resistance pending foreign intervention is sought.

The Concept

This model is based on the emplacement of fixed defences, designed to raise the cost of invasion and purchase time for reinforcements to arrive. The first step is to identify a close group of relatively small islands, near enough to be mutually-reinforcing (the entire group preferably no more than 50-70 km in diameter) and commanding an unobstructed view of the most likely hemisphere of attack.

Main Systems

For purposes of illustration, we will indicate particular systems, because it is only the combination of specific features of the systems used that would render this model viable. On these islands, the following systems could be installed in a scattered and concealed fashion:

– An Arabel radar and 3-6 SAMP/T launch systems for long-range air defence;
– A medium-range surface-to-air battery- preferably the Norwegian NASAMS 2, given its newfound ability to fire the Enhanced Sea Sparrow Missile and its extremely dispersed sensor architecture;
– A coastal anti-ship missile system, such as the NSM Coastal Defense System, covering a hemisphere of approach to the entire chain.

These systems would be dispersed and mutually reinforcing throughout the group of islands selected. Needless to say, siting of the systems, networking, command and control and interoperability of the systems are the crucial factors for success. Both medium and long-range SAM systems can be widely dispersed from their guidance radars, and NASAMS 2 in particular provides eight mobile radar units in each battery of twelve launch vehicles.

The selection of systems here is specific and advocated as the best combination available for this role. Specifically, NASAMS 2 and NSM were developed for very similar operational environments. Though other systems could be substituted, this should be done with great care for the overall viability of the system. For example, a less-capable medium-range missile would be a critical weak link, and an anti-ship missile lacking either stealth characteristics or supersonic speed would pose a less serious obstacle.

Supporting Capabilities

In addition to the primary defensive systems, troops with shoulder-launched SAMs and anti-tank missiles could be employed to deter any attempt to infiltrate the islands by amphibious assault, helicopter or submarine.

Dual-purpose medium-calibre guns such as the Otobreda 76mm or Bofors 57mm could be emplaced ashore in strategic locations to deal with leaker aircraft, littoral-capable missile boats, amphibious assault and, to some extent, incoming missiles (both systems are claimed to have a credible CIWS capability). Naval artillery, as distinct from most land-based artillery, is a definite added value. The 76mm with Vulcano guided ammunition will have a 40km range, very useful for dispatching small craft, and Otobreda’s 127mm gun triples that, making it potentially a very potent anti-ship system.

The system could also be supplemented with acoustic mines or other antisubmarine measures. Since the system would need UAVs or helicopters to perform over-the-horizon scouting and targeting as well as transport, it may make sense to employ helicopters in an ASW and light anti-surface role as well.

Comparative Advantage

This defense system has some drawbacks. It is not cheap and is certainly no guarantee against a determined enemy. But it is cheaper than maintaining a fleet of warships or aircraft on patrol, and would arguably be more effective in its designed role, which would be to blunt the initial incursion and purchase time for reinforcements to arrive. In contradistinction to traditional methods of fortification, including naval mines, this system has the potential to inflict much greater damage on an attacking force and cannot be inexpensively removed by minesweepers. It deprives the enemy of the ability to maintain an unopposed maritime presence in the region, rather than merely denying the ability to pass through choke points or land troops by sea.

It will be pointed out that this system remains hopelessly inadequate against a modern air force with stand-off cruise missiles. In the numbers game, it cannot even begin to break even. But denying the enemy fixed or easily-located targets and providing a serious threat that requires risk and potentially massive ordinance investments to iradicate works as a first-stage defence strategy and provides some serious deterrence potential.

“Poor Man’s Version”

It would, of course, be possible to create a similar (and probably more dispersed) system using tools at hand- any combination of MLRS systems, SAM systems and tube artillery could theoretically be used to make life difficult for an incursion. However, against an advanced opponent, the lifetime of each unit after first use would be miniscule, naturally depending on the SAM systems employed to cover them.

A further temptation is to use such a system to back up a fully dug-in defence of the disputed islands. While there is no doubt that a force fighting on prepared ground and employing asymmetric tactics can inflict massive casualties on an invader, as the Japanese did on Iwo Jima and other Pacific islands, the loss of life would be extreme. This brings up another advantage of the original model, which is that large numbers of troops do not have to be invested in a potentially high-casualty defense scenario.

Disclaimer: This article is not meant to comment on the advisability of this approach in any real-world situation, but only to illustrate the military viability of the concept. In the real world, such a step should only be taken in a situation where violent confrontation has already occurred and the threat is imminent; in any other case, militarising a disputed chain might provoke rather than deter conflict.

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