Phalanx Mk 15 CIWS – Block 1B
The recent attack on the US Navy by pirates (successfully fought off, thank goodness) already had me thinking about the latest version of the Phalanx Close In Weapons System (CIWS), and when a commenter at Hell in a Handbasket wondered about the capability of the CIWS to engage surface targets, I decided to do a quick post on the subject.
CIWS, of course was originally designed to defend our ships from high-speed missiles. The six-barrelled 20mm gun is a last-ditch defense against incoming ship killers. Over the years, the original Block 0 models (introduced in 1980) were supplanted by the Block 1(1988) and 1A (1996). Now, the Block 1B (also referred to as “Phalanx Surface Mode” or PSUM) improves on these, and (maybe more importantly) provides for defense against surface targets like small boats and personal watercraft as well as against slower aircraft like helicopters. Forward-Looking IR and video tracking/targeting, Ku-band radar, and longer barrels providing better accuracy are among the most notable improvements over earlier versions. Capability against missiles is unimpeded. Let’s hope that maintenance and combat readiness, long a problem with these units, also improves.
Although it might seem that these improvements might be a response to the suicide attack against USS Cole in 2000, that isn’t the case. Prototypes were tested in 1999 and installation of Block 1B systems, either upgrades of earlier versions or new builds, has been going on since 2000.
For more background information on the Phalanx, see (of all places) the Pakistan Military Consortium.
Earlier model Phalanx (left) vs. Block 1B (right):
Note the FLIR and video tracking systems mounted on the left side of the Block 1B unit.
Here is more detailed info from Raytheon. The source is the .pdf where I found the image above and contains additional background. Here’s the goods on the Block 1B:
Today, surface combat is most likely to occur in near shore, littoral environments. This scenario places ships and their crews at risk to an increased number of threats including small, fast gun boats, standard and guided artillery, helicopters, mines and a variety of shore launched anti-ship missiles. These threats demand a new generation of ship defense capabilities – Phalanx Block 1B.
Raytheon’s Phalanx Block 1B Surface Mode is a complete weapon system to counter threats of today and tomorrow. With an integrated FLIR and operator control panels merged with a proven anti-ship missile defense capability, the Block 1B system is unique in the world. The system has been thoroughly tested in real world scenarios against a variety of ship defense threats and will soon be deploying on U.S. Navy vessels.
Optimized Gun Barrels
The original M61A1 gun barrels were designed for short bursts and are subject to wear and increased dispersion patterns. The new OGBs are 18 inches longer, substantially thicker and include both a barrel brace and muzzle restraint to improve life expectancy and projectile dispersion patterns. In addition, the optional Enhanced Lethality Cartridge (ELC) will provide a 50 percent increase in penetrator mass.
To provide its unique Surface Mode tracking and engagement capability, Phalanx Block 1B incorporates a Thermal Imager with Automatic Acquisition Tracking. The system operates in the 8–12 micron wavelength and is mounted on a stabilized pedestal attached to the existing Phalanx Track Antenna radome. This system provides a reliable day/night passive search and track capability against slow-speed air threats and surface craft, while improving Anti Air Warfare performance in multi-path and glint environments via enhanced angular track accuracy (50–100 microradians) against the high-G maneuvering ASM.
- Autonomous detect, prioritization, track, engagement and kill assessment of air targets from wave-top to steeply diving
- Day/night detect, identification, track and engagement, and kill assessment of surface craft and low-speed aircraft
- Remote designation available from other ships’ sensors against air and surface targets
- Interface and control to provide fire-control and search sensor capability for other shipboard gun and missile systems
Here are a couple of CIWS units pulled from USS Missouri on Wasted Disk Space’s Battleship Missouri Memorial:
It’s a bit unclear to me what the exact status of Missouri’s CIWS systems is. According to the USS Missouri FAQ:
Did Missouri have the Phalanx system on board? Did and do. We sailed in 1986 with four of the Phalanx, CIWS (Close-In Weapons System) units on board. When we decommissioned the Navy took them away to use on other ships and has only given 2 of them back to us (so far).
MO contacted the FAQ admin and found out that the two units have been remounted, one port-forward and one starboard-aft. [UPDATE: The pic above is “almost certainly” the two returned that have been remounted.] They have part of a third unit and continue efforts to get the rest and a fourth unit.
This is the schedule for Block 1B installations according to a recent (Feb 2006) US Navy Budget Item Justification Sheet (.pdf):
(FY2005 & Earlier: 34 total)
Here’s a nifty diagram of the Phalanx family evolution from Block 0 up to the Block 1B (and actually beyond Block 1B and into the SEA RAM program which replaces the 20mm gun with a Sea Sparrow/Sidewinder mongrel missile for greater range…but that’s another post). Click for a better look:
The slide is from an awesome Raytheon .pdf at DTIC from early 2000. Unfortunately, there seem to be a couple of problems with the sheets, particularly with one comparing the accuracy of the older gun barrels with the new ones.
Last but not least, don’t forget the C-RAM (Counter Rocket Artillery Mortar) system, a land-based Phalanx currently in use in Iraq. Here’s a pic:
The C-RAM uses a Block 1B, as you can tell by the FLIR and video gear on the left-hand (far) side of the “R2-D2” dome. I’ve had no word on the the C-RAM since its deployment to the Sand Box last summer. I know for a fact that the military is trying to keep a lid on the actual performance of this beast, so maybe that’s why. Defense Industry Daily noted last fall that Northrup Grumman won a contract for more of the systems, so decision-makers must be optimistic of the C-RAM’s potential regardless of current success.
Also, in my earlier article I wrote that the C-RAM’s HEIT-SD (High-Explosive Incendiary Tracer, Self-Destruct) ammunition “explode[s] in mid-air, raining shrapnel at the incoming rounds in order to destroy or deflect them”, which isn’t the case. The self-destruct feature is really intended to prevent the rounds from falling into friendly areas on the ground and causing damage. At up to 4,500 rounds per minute, that would be some seriously un-friendly fire raining down and would not win many hearts and minds.
Ship-borne Phalanx systems used to use depleted uranium rounds, but more recently have switched to tungsten. So, fish, keep your heads down!
(NOTE: There seems to be a lot of confusion about the “Block 1B” designation which apparently stems from the naming convention of the Block 1 series. Incremental improvements to Block 1 were “Block 1 Baselevel 0”, “Block 1 Baselevel 1”, and “Block 1 Baselevel 2”. These were replaced by the “Block 1A”, which is being supplanted by the “Block 1B” which this post primarily deals with. Look on the Phalanx family slide above and you will see that the Block 1 baselevels are marked “Block 1 B/L 0” and so on, and I think this has some folks thinking that it means “Block 1 B”. It doesn’t.)