The Navy – and, I suspect, many naval observers – have a completely unrealistic idea about mine clearance (MCM, mine countermeasures) and the speed with which it occurs. The Navy would have us believe that half dozen LCS-MCM vessels are all we need. On a particularly honest day, you might get a Navy admiral to grudgingly admit that a few MCM operators in a RHIB might also lend a hand but that’s the extent of the clearance assets that the Navy is developing.
The problem (well, one of many!) with the Navy’s MCM vision is that it is excruciatingly slow and I’ve pointed this out many times. I won’t rehash the overall discussion. Instead, I’d like to take a deeper look at the heart of the MCM system, the Airborne Mine Neutralization System (AMNS, AN/ASQ-235).
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Airborne Mine Neutralization System - Empty Carrier Being Recovered |
As enumerated by the Navy, mine clearance consists of three basic steps:
Detect possible mines with a broad area search
Identify mines with small AQS-20A towed sonar
Destroy mines with AMNS/Archerfish
This already sounds slow, doesn’t it? Searching an area twice before you can neutralize the first mine is not a process designed for speed. But, I digress …
The AMNS is the neutralizer which is the Navy’s less-violent euphemism for the destructor system. The system consists of a helicopter (MH-60S or MH-53E) which mounts a carrying cradle (Launch and Handling System, LHS) for four mini-unmanned ‘torpedoes’ which are individually guided to a mine and then blow themselves up, destroying the mine in the process. Thus, each helo can destroy a maximum of four mines before it has to return to the host ship to reload or replace the cradle.
Archerfish is the destructor for the AMNS. It is a small, lightweight (34 lb), expendable, remote controlled, underwater vehicle which carries a small shaped charge to destroy mines one at a time. It is a suicide vehicle since it is destroyed each time it is used. Each Archerfish contains a sonar, video camera, and light to assist the operator in reacquiring the mine.
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| Archerfish |
Unfortunately – and repetitively inefficiently - , AMNS has to reacquire the previously detected mines and the Archerfish is then guided to the mine by a sonar sensor operator on the helo, using a fiber optic communication cable, positive identification is established, and the destructor is command detonated.
The destructor reacquisition and approach phase is not a lightning fast operation as some might imagine. The destructor doesn’t approach the target at 50 kts, ram into it, and explode. Instead, the approach is slow and time-consuming. From the BAE Archerfish data sheet we get a sense of the slow, deliberate approach process,
Excellent maneuvering characteristics enable Archerfish to traverse the target to obtain pictures and sonar images from a variety of angles. Archerfish approaches the target under command guidance. In the final stages of the approach, the Archerfish sonar and video also acquire the target and transmit more detailed information to the operator via the fibre optic link.(1)
Shown below is the launch system with four destructors.
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| AMNS with Four Archerfish Loaded |
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| AMNS - Note the Size of the LHS Mounting System |
Setting aside the first two steps of the MCM process which are the initial survey and subsequent sonar identification, the speed of the AMNS portion is determined by the steps below. The time estimates are just ballpark figures and would depend on a multitude of factors but they offer a decent approximation.
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AMNS Speed of Operation |
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Step |
Time |
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Configure helo for LHS carry |
Hours?(a) |
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Load LHS |
1 hr |
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Transit to operation area |
30 min |
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Lower LHS |
10 min |
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Launch destructor |
10 min |
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Locate and identify target mine |
15 min |
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Detonate |
instantaneous |
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Repeat until four destructors have been consumed |
- |
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Return to ship |
30 min |
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Reload LHS |
30 min |
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Repeat cycle |
- |
(a)demonstrated on an LCS video; very lengthy process
The overall time for a single cycle with the helo already configured for the AMNS and with the LHS already loaded is on the order of 2h:20m. That equates to a mine clearance rate of 4 mines per 2h:20m or 1 mine every 35 min or, roughly, 2 mines per hour. This is the best case clearance rate but the actual rate is lower since the helo has to return for maintenance, crew changes, fuel, etc., multiple times over the course of a day so the actual clearance rate is less than 2 mines per hour.
It is also important to note that the helo is also used for the initial broad area detection sweep, using the Airborne Laser Mine Detection System (ALMDS) and that time has to be included in the overall mine clearance rate so the effective clearance rate is further reduced to around 1 mine per hour on a sustained basis.
The AMNS system, assuming it works as advertised – and they never do - , is decisively effective, in that it blows up the mine, while also being utterly inefficient. Clearing minefields one at a time is the worst possible approach especially in combat where speed of clearance is vital. Ships waiting for passage through a chokepoint or amphibious forces waiting to land can’t wait while mines are cleared one at a time and yet this is the system that the Navy has decided on for its future mine clearance capability.
We should note that the Navy is also working on a rapid sweep technique using the Common Unmanned Surface Vessel (CUSV), however, the effectiveness of sweeps against modern smart mines is highly questionable. As with so many other weapon systems, we desperately need to test the sweep system under realistic conditions against actual smart mines to determine whether the system can work, at all.
AMNS is fine for peacetime or very limited mine clearance operations but in war mines are likely to be laid by the thousands and AMNS will be completely unsuited for the task. We need to develop highly efficient, wide area sweeping and neutralization capabilities.
AMNS is yet another example of the Navy developing peacetime capabilities instead of large scale war capabilities. We must break out of this peacetime mentality that the Navy is married to and start preparing for real war.
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(1)https://www.baesystems.com/en/product/archerfish-mine-neutralisation-system
