The LCS was originally tasked with three missions: mine countermeasures, anti-submarine warfare (ASW), and anti-surface warfare. We’re going to take a closer look at the ASW mission.
To review, in the ASW role the LCS was originally intended to be a stand-off vessel that would launch a variety of remote, unmanned vehicles and deploy a sensor net. As such, the ship did not need its own sonar systems or anti-submarine weapons. Unfortunately, the Navy scrapped the ASW module when it was found to offer no improvement over existing capabilities (Navy-speak for less capable than existing systems, but I digress). The current module consists of a ship mounted Variable Depth Sonar (VDS), towed array, torpedo decoy (presumably Nixie or something similar), and a helo.
Thus, the LCS is now an up close and personal participant in the ASW mission. However, the fact that the ship was not designed for active involvement in the ASW process leads to several issues.
Helo Coverage – As we’ve demonstrated, helos are maintenance intensive and a single helo (LCS-1) or two helos (LCS-2) can only provide very spotty coverage. In addition, the MH-60 series helos can only carry two torpedoes which severely limits the number of shots and rearming is not a quick process.
Towed Array – The planned towed array is a major issue. First, a towed array can’t be deployed in shallow water which was the LCS’ entire rationale for existence! Second, the towed array presents a major problem as it impacts the ships speed and performance. Some say that the LCS was intended to use its speed to “dance” around subs and torpedoes (though that’s most likely an after-the-fact rationalization rather than a designed intent). Accepting that premise for the sake of discussion, one can see that a towed array severely limits the ship’s speed. With an array deployed, the ship can’t use its speed and becomes an easy target. On the other hand, if the array isn’t deployed the ship can’t detect submarines and becomes an easy target. Bit of a Catch-22, there, huh?
Sonar – The ship’s size and shape seem to preclude addition of a typical hull-mounted sonar, especially for the LCS-2 version. I’ve read reports that suggest that the water jets and ship’s internal machinery noises preclude hull mounted sonar due to severe self-noise masking. I consider that unconfirmed though plausible.
Acoustics – While some reports claim the LCS water jets are quieter than conventional propulsion systems, the majority of documents seem to indicate that the water jets are enormously loud acoustic beacons. Anyone who’s seen film of the jets in operation would find it hard to believe that the system is quiet enough for ASW work. Further, the ship was not built with acoustic quieting integrated into the design. Unlike the Spruance class which was built from the keel up as an ASW platform, the LCS lacks sound isolating machinery mounts, internal acoustic insulation, a Prairie/Masker type quieting system, and the other acoustic features built into the Spruances. So, in addition to the water jet issue, the ship’s internal noise is not quieted. The ship is an acoustic beacon for enemy submarines. It’s hard to be the hunter when you’re louder than the prey!
ASW Weapons – Like the dog that chases the car (what’s he going to do with it if he ever catches it?!) the LCS has no ASW weapons if it ever finds a sub. Yes, the helo might be available but that’s not a likely scenario and the helo is limited to two shots. The LCS, itself, has no ability to defend itself or initiate an attack and certainly no capability to react to a surprise, close range encounter.
VDS – The Variable Depth Sonar (VDS) is potentially a useful sensor although, because of the need for complete automation due to the insufficient crew size, the VDS model being acquired requires 20+ minutes to deploy or retrieve. While ASW is a slow game, this still limits the ship’s movement and response time especially if a torpedo is inbound!
In summary, ASW requires a platform built from the keel up with integrated acoustic quieting features, on-board weapons and sensors, and torpedo countermeasures, none of which the LCS has because it was never intended to be intimately involved in the ASW fight. This also illustrates the flaw in the modular philosophy but that’s an issue that we’ve already covered in a previous post. Trying to force the LCS into a role it isn’t optimized for is going to result in an ineffective platform that makes a better target than attacker.
Employment of LCS squadrons and the use of good operational tactics can mitigate some of the problems but the flip side of that is that clustered numbers of LCS’s will simply provide a loud, target rich environment for enemy subs.
To be fair, I’ve advocated a low end, less than optimal ASW platform that can be built in numbers, however, the key feature of that type of vessel is cheapness and the LCS doesn’t even come close to meeting that requirement.
All of this leads to the question of whether the LCS could be successfully adapted to ASW? The answer is that it’s possible but it would require extensive redesign of the basic seaframe. The ship needs all the quieting measures I’ve described, probably quieter conventional engines, a rapidly deployable VDS (adapt an over-the-side helo dipping sonar?), a short length multi-function towed array, hull mounted sonar, torpedo decoys, anti-submarine torpedoes, and a Russian style (RBU series) short range depth bomb as well as an integrated ASW combat control software suite. If all this was done the LCS would no longer be an LCS, meaning that it would no longer be a modular platform. Instead, it would be a dedicated shallow water ASW vessel. Ironically, in that form it would offer a credible purpose and functionality to justify its existence as opposed to the useless vessel it now is.
By the way, does a vessel with two helos, a towed array, hull mounted sonar, anti-submarine torpedos, Prairie/Masker quieting, and torpedo decoys sound familiar? It should - it's called a Perry. If only we had had dozens of those that could have been updated a bit ...