Navy's Blue Ridge Class Command Ships Once Had This Wacky Air Defense Missile System
Although the ability to fire Sea Sparrow missiles seems impressive, in actuality the system was lacking in almost every regard.
With USS Blue Ridge (LCC-19) recently coming out of a major upgrade and maintenance period, The War Zone ran a feature on the often misunderstood, half century old class of command and control ships. After posting the article we got a flood of email, comments, and instant messages from people who had served on the ships or visited them for a period of time during their careers in the military. We were told repeatedly how great the food was, how the ships' abilities were far more limited and even neglected in decades past, and other interesting tidbits of information. Maybe the most interesting was about the class's armament. It turns out the vessels were once equipped with an austere point air defense capability, one that is almost laughably incapable by today's standards.
At its commissioning, USS Blue Ridge was outfitted with a pair of twin Mark 33 three inch guns mounted amidships. These rudimentary deck guns were quickly augmented by a pair of Mark 25 box launchers installed nearby. The Mark 25s housed early versions of the RIM-7 Sea Sparrow surface-to-air missile—which was adapted from the air-to-air missile of a similar name, specifically the AIM-7E.
The box launchers themselves were adapted from RUR-5 ASROC anti-submarine rocket launchers that were first introduced around 1960. The Mark 25 contained eight RIM-7s, with the launcher being bulkier than the Mark 29 launchers used on aircraft carriers and amphibious assault ships over the last few decades. The reason being is that early RIM-7s didn't have folding fins that pop-open as they leave their launch cells, and as we mentioned earlier, the launcher was originally built to accommodate the ASROC. It wasn't until the RIM-7H that the new fin configuration was put into production.
This launcher-missile combo was trained to a manually operated turret that had a pair of radar illuminators fixed on both of its sides. This system was called the Mark 115 Manually Aimed Target Illuminator or Manned Director. Wherever this turret was pointed by a sailor standing behind it looking through a scope, the box launcher would point too. When a missile was fired, the idea was that it would immediately lock onto the target being "painted" by the manned illuminator and streak out directly toward it.
Targeting was a goofy affair in which the guy operating the illuminator would be directed via voice commands to where shipboard radar was seeing a target. The, operator would then swivel the contraption best he could in the direction and elevation he was being told. The system didn't require perfect visual targeting by the operator as the beam was fairly wide, but he had to keep tracking the target in order for the semi-active radar homing RIM-7 missile to make its way to the target and destroy it.
The system became known as the Basic Point Defense Missile System (BPDMS) and was rapidly deployed to ships in the 1970s as a modular design that could take the place of archaic anti-aircraft guns. Clearly it had major limitations. First of all, earlier RIM-7s were terribly suited for surface-to-air missile duty and had anemic range. Half a dozen miles or so was likely the actual reach of this system. The AIM-7E Sparrow missile was designed for sustained cruise in thin air with the kinetic advantage of being launched by a fighter already moving at hundreds of miles per hour, not from the surface of the ocean out of a can. Its centrally-mounted maneuvering fins were also far from ideal for quick reactionary adjustments that a point defense missile systems needs to swat down incoming missiles and aircraft.
Later RIM-7 variations would fix many of these issues, but it wasn't until the redesigned RIM-162 Evolved Sea Sparrow Missile (ESSM) was introduced in 2004 that most all of the missile's deficiencies were overcome. The latest versions of the ESSM don't even rely on any kind of radar illuminator at all, leveraging data-links for initial and midcourse guidance and an active seeker for terminal homing.
The system was also limited at night and especially in foggy conditions, which are common on the high seas. The ability to engage multiple targets relatively quickly was also sorely lacking, but at least the ship had something to defend itself from enemy aircraft and from Russian anti-ship missiles that could leak through a battle group's defensive screen. Still, this was a cobbled-together last resort defensive system, and with the installation of the Mark 15 Phalanx close-in weapon system in the early 1980s, the need for marginally effective BPDMS aboard the Blue Ridge class was questioned.
USS Blue Ridge and USS Mount Whitney soldiered on with the setup into the early 1990s, when the Mk 25 launchers and Mk 115 directors were finally removed.
With the Navy investing heavily in these ships—their out of service dates now placed over two decades into the future—it will be interesting to see if the seagoing force provides them with enhanced defensive systems once again. A pair of 25mm Bushmaster cannons on remote weapons mounts were added in recent years for defense against swarming boat attacks and other lower-end threats, and the ships still have their fore and aft Mk 15 Phalanx mounts, but nothing that can reach beyond couple miles.
The SeaRAM system, which melds the RIM-116 Rolling Airframe Missile and the Phalanx's independent search and fire control radars into a single self contained package, seems like the most likely option. They could be mounted amidships near where the Mark 25 launchers once sat. It's also possible that a single SeaRAM system could replace one of the Phalanx mounts.
The combination of SeaRAM and Phalanx seems to be the Navy's defensive mix of choice for ships operating independently in potential super anti-ship missile engagement zones. The Navy's Arleigh Burke class destroyers forward based in Spain have been modified to this configuration. USS Mount Whitney in particular operates independently in the Mediterranean and even the Black Sea.
The somewhat scary thing is the BPDMS equipped American aircraft carriers, amphibious assault ships, and dozens of Knox class frigates for multiple decades during the Cold War before they were replaced by far more automated and capable systems. One has to think just how bloody a full on barrage of anti-ship missiles by a Russian battlegroup, SSGNs, and/or strategic airpower would have actually been to the American Navy of that era. I don't think it would have been pretty to say the least.
If anything else, the Blue Ridge class's old manually operated air defense system, which lacked any hard integration with an overall sensor and weapons architecture, is a reminder of just how far the U.S. Navy has come in regards to point defense in the last 50 years.
Contact the author: Tyler@thedrive.com