Royal Navy aircraft carriers – vulnerable or fit for the fight?

There have been frequent suggestions that aircraft carriers are inherently vulnerable and have been rendered obsolete by a new generation of weaponry. Here we look the range of conventional threats the carriers might face in a high-end conflict and how the RN and the Queen Elizabeth Class are configured to deal with them.

The Russians have called the QEC “large and convenient targets”. A cute sound bite that is frequently rehearsed in various forms across the media and helps create the illusion that they are just passive floating airfields, lacking their own offensive power or the ability to defend themselves. Some forget that a prime purpose of the carrier battle group is to go on the offensive and strike in a proactive way, and if necessary to eliminate what may threaten them before it may mount an attack. That said, it would be complacent to think that any aircraft carrier is invulnerable. Recent developments in stealth aircraft, hypersonic and ballistic anti-ship missiles and ultra-quiet submarines are a threat to all surface combatants. Even the mighty US Navy is stretched to cope in this environment, so how much more is the threadbare RN at risk?

On the day HMS Queen Elizabeth arrived in Portsmouth for the first time we met Commodore Andrew Betton, commander of the UK Carrier Strike Group and asked him if he considers the RN can offer the ship adequate protection, particularly if faced with high-level threats. He replied “The maritime task group operates with layers of force protection, some of which is delivered by ships & aircraft. We also have satellite surveillance to support our understanding of what’s around us. We can bring in extra layers of protection when needed. Every deployment of the carrier & structure of task group around will be based on an intelligence assessment of the threat likely to be faced and the operational tasking.” These layers of protection and defensive measures the UK is able to provide the QEC are worth closer examination.

Seven layers of protection

1. Situational awareness

The very outer defence of the Carrier Strike Group (CSG) is really about situational awareness. This intelligence can be provided by aircraft such as the P-8A Poseidon, satellite imagery, undersea acoustic sensors, and even basic human intel could all contribute to this accumulation of knowledge. Depending on the circumstances and the ability to collect this data, this kind of information may be plentiful at times or almost nonexistent on other occasions. History has proven for example, that land-based aircraft, even if dedicated to the task are almost incapable of sustaining round-the-clock protection or intelligence to naval vessels. It is always extremely challenging to secure and maintain real-time data on distant threats. This works both ways, to attack the CSG from distance, the enemy also needs accurate location data on ships that may cover more than 400 nautical miles (nm) in 24 hours.

The QEC and some of the RN’s escort ships now benefit from some exceptionally capable new radars. The high-resolution Artisan 3D (Type 997) radar has a range of over 100nm. The carrier’s (Type 1046) S1850M long range air search radar can detect aircraft out to 200nm. The large size of the QEC allows the aerials to be mounted high above the waterline, extending the range at which sea-skimmers can be detected.

2. Carrier aircraft

The first active line of defence are the F-35B Lightnings flown from the carrier itself. Able to strike land targets, and intercept aircraft and attack ships that threaten the CSG. Air defence of the fleet is an absolutely key capability for the carrier and this is often overlooked in discussions about the strike role. A major strength is that the F-35 has exceptional sensors and can be networked with other aircraft to monitor a large area, feed data back to the carrier and respond quickly. A potential weakness here is the un-refuelled combat radius of the F-35B (without drop tanks that compromise stealth and handling) at approximately 500nm.

The Searchwater radar of Crowsnest helicopter has an approximate maximum range of 150nm and operate up to 450nm away from the carrier with sorties lasting up to 4.5 hrs. As the range of anti-ship missiles increases, the combat radius and limited number of aircraft (12-24?) that can be deployed against potential launch platforms become critical.

3a. Area defence (air)

The Principal Anti Air Missile System (PAAMS) carried by the Type 45 is possibly the best and naval air defence system afloat anywhere in the world. It is theoretically capable of detecting and simultaneously engaging multiple aircraft and missiles travelling up to Mach 4. The Sea Viper missiles provide an air defence umbrella that extends out to about 65nm over the CBG.

Once the propulsion problems have been fully cured by the mid-2020s, with just six Type 45s, the RN is likely to be able to assign a maximum of two these destroyers for escorting the CBG. Even if the MoD actually holds sufficient missile stocks for all the Type 45s to embark a full outfit, they can carry a maximum of 48 and cannot be replenished at sea. One can have great confidence an initial saturation attack would be successfully repelled, but repeated attacks could exhaust limited ammunition quickly. The comparable AEGIS-equipped Arleigh Burke destroyers of the USN can embark up to 96 missiles and the Ticonderoga cruisers up to 122 missiles of various kinds. The US Carrier battle group would typically be escorted by 6 of these AEGIS ships. At present, the RN has no ability to destroy ballistic missiles (anti-ship or otherwise) but there is the potential for the RN to buy the Aster Block 1NT for the Type 45 in future.

3b. Area defence (underwater)

Of all the threats to the CBG, the submarine presents the most danger as they become increasingly quiet and hard to detect. Submarines are usually the best means of finding and sinking other submarines. Of the seven SSNs possessed by the RN, it would be expected that one will be assigned to protect the CBG (The USN typically assigns 2 SSNs to a carrier group). Usually, the SSN will work as a ‘freelancer’, not especially close to the CGB but in the best tactical position to intercept and track hostile ships or submarines. The Merlin Mk2 helicopters operating from the deck of the QEC and the escorts are the only other means of prosecuting submarines (unless ASROC missiles are purchased for the Type 26 Frigates). Finding submarines will be the primary job of the Type 23/26 frigates. Their excellent Type 2087 towed array sonar is the usually the best tool for detection at a safe distance away from the CBG. They will then direct the Merlin to the target which can be precisely located using its FLASH dipping sonar. The escorts all have bow-mounted sonars but detection ranges in both passive and active modes are usually considerably less than that of the towed array, but which time a submarine could be close enough to have achieved a firing position. Unfortunately, despite the quiet electric motors that propel the Type 45, the QEC and the supporting Tide-class RFAs, they all have noisy diesel engines and auxiliary machinery bolted directly to their hulls. Without dampening measures, this radiates noise and vibration into the water which interferes with sonars and may aid enemy submarines in locating the CSG.

The P-8A Poseidons may also be able to contribute to the ASW effort surrounding the carrier, but this would very much depend on the area of operations.

In broad terms, area defence against submarine and air threats is much easier to conduct in the open ocean. In the littorals, close to land and in congested and noisy shallower seas, defence of the carrier becomes significantly harder.

3c. Area defence (surface)

A rather obvious gap in the CSG defences is the lack of medium or long range anti-ship missile carried by the RN’s escorts (from 2018 to around 2030 when the FCASW project may bear fruit). When the Sea Venom missile comes into service the RN will have an excellent weapon for use against fast attack craft or corvettes, but attacking major warships must be delegated to the F-35s or a supporting submarine.

Sea Viper and Sea Ceptor. The ship-launched missile systems key for air defence of the CSG

4. Point defence

Missiles or aircraft that evade the area defences should then encounter the point defence Surface to Air Missile (SAM) systems that protects individual ships or a few ships in close company. A point defence SAM would typically have a maximum range of 10-12 nautical miles. The QEC has no point defence system of its own and will entrust this task to its escorting ships. Other navies think differently. The French carrier, Charles de Gaulle is fitted with 16 x Aster 15 SAMs and 2 Sadral SAM launchers. US carriers have both RIM-7 Sea Sparrow SAM and RIM-116 Rolling Airframe SAMs. The new Sea Ceptor SAM fitted to the Type 23/26 frigates looks to be very effective in this role and has significantly greater range than the Sea Wolf system it replaces. The point defence ‘goalkeeping’ mission requires the escort to stay in close touch with the carrier and its arcs of fire may be restricted by the carrier or other ships. At times the frigates may need to operate at some distance away from the carrier in order to deploy towed array sonar and listen for submarines, undisturbed by the self-generated noise of the CSG.

The Type 45 can also provide point defence using its shorter range Aster 15 missiles but the number of ships and available missiles is again the problem. Fitting at least a few Sea Ceptor cells to the QEC would not be especially difficult and this omission has everything to do with saving money and nothing to do with tactical wisdom.

5. Close in weapons systems

The QEC has a very standard CIWS fit of 3 x 20 mm Block 1B Phallax guns and 4 x 30mm Automated Small Caliber Guns (ASCG). The ubiquitous Phalanx system is used by many navies across the world, is simple and reliable but how it would perform in saturation missile attack is unknown. The ASCGs are cued by electro-optical mounts high on the ship and can be controlled from the ops room. They would probably be very effective against small boat swarm attacks. It is assumed the QEC will also be fitted with a variety of decoy launchers and the Surface Ship Torpedo Defence (SSTD) decoy system. The USN is fitting an active variant of SSTD on its carriers that launch mini torpedos to destroy inbound torpedos, rather than just attempting to confuse them.

6. Light weapons and force protection measures

The inner layer of protection consists of a selection of removable M2HB machine guns and Mk44 mini guns on pintle mounts around the ship. All RN vessels, man these weapons when entering or leaving port as protection against attack from small craft or drones. In battle conditions, they may also serve as useful last-ditch defence particularly against aircraft or small boat swarms. Being manually aimed, they are of minimal use against missiles.

7. Damage control and survivability

If the worst happens, the QEC have been carefully designed to withstand significant battle damage. The designers wisely avoided the pressure to reduce costs by cutting corners on construction standards. This kind of protection would be very difficult and expensive to retrofit at a later date. Resistance to blast, splinter and flooding provides reassurance that the ship can survive some hits or near misses without catastrophic structural damage and is able to float, move and fight in difficult conditions. The RN is also recognised as a world leader in training its sailors in effective damage control.

Conclusions

This is a whistlestop tour of a very complex subject but this basic assessment shows there are weaknesses that restrict where the QEC could be safely operated without assistance from the US Navy and other NATO nations. By withdrawing from standing commitments, at a stretch, the RN will probably be able to muster 2 destroyers and 3 or 4 frigates to provide sustained escort to the carrier. The QEC and its bare minimum supporting assets do offer the option of mounting an independent British operation but only against a lesser adversary (ie not Russia and certainly not China). Even a ‘Falklands conflict’ style operation would still entail considerable risk, given the slim escort and lack of strength in depth.

No one seriously expects the UK to take on a peer-level opponent alone but beyond the apocalyptic scenario of major state-on-state conflict, the carriers still have huge utility. Even if the RN cannot act independently, the QEC significantly adds to NATO naval capability and deterrence which is presently inadequate in the European theatre. The QEC also come with all the other attendant soft-power capabilities such as diplomatic and trade missions, humanitarian and relief operations and the ability to help enforce foreign policy without firing a shot or putting troops on the ground. They are also highly valued by the US who see them as able to plug gaps to relieve pressure on their fleet.

Asked if he expects to operate mostly with coalition warships Cdre Betton said; “Coalition operations are attractive as they spread the burden, and give us a shared authority. But the new carriers are a capability that is sovereign at core and allow us to act unilaterally if we wish”.

 

 

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