Think Defence today has a post on the difficulty a potential foe faces in finding a carrier at sea. It is (like virtually all content there) well worth reading the whole thing.
Aircraft carriers are difficult to detect.
Perhaps more importantly, they are difficult to identify. Regarding the difficulty of detection, the seas are very big and, in comparison, even the biggest of aircraft carriers are very small. Modern maritime patrol aircraft (MPA) have radars that have ranges of hundreds of nautical miles (nm) but oceans extend for thousands of nautical miles.
Moreover, radar impulses can be detected by electronic support measures (ESM) systems at significantly greater range than the radar can detect the platform (air or surface or even submarine) carrying the ESM. In wartime, an MPA using its radar gives itself away, opening the way to it either being intercepted and shot down before it can locate the carrier, or to the carrier simply altering course and avoiding the MPA.
Of course, MPAs also have ESM, but this works only if the carrier and its task group (Carrier Battle Group: CBG) are emitting electromagnetically.
But if the CBG has adopted strict electromagnetic silence (and it can do so & this is exercised), then there is nothing to detect. So the MPA is reduced to the Mark 1 eyeball as its only useful sensor.
When I think of most post-World War II significant carrier operations, I generally consider their use in Korea, Vietnam, and of course, operations in the Persian Gulf, where they essentially stayed in fixed positions, and acted like additional airfields. The lack of significant enemy ability to interdict our forces at sea allowed us to sacrifice one of the carrier task forces’ greatest assets, mobility, at little risk.
Prior to World War II, it was widely assumed that operating carrier forces within range of enemy land based airpower was a recipe for disaster, and that shore based airpower would quickly sink or damage any carrier force. The first clue that this wasn’t quite so true came December 7, 1941.
Successful, if not highly fruitful, US attacks against Japanese outposts in early 1942 showed that by choosing the time and place to attack, carriers could operate to impede or suppress shore based airpower, and retire out of range before an effective Japanese counterstroke could be brought to bear.
The Fast Carrier Task Force (TF38/TF58) would often operate in wide ranging support of amphibious landings in the Pacific War. While FCTC would of course raid the target of a landing, it would also strike enemy installations far afield, to deny the enemy the ability to reinforce the defense of our objective, and to a degree, to conceal our objective. The ability of the FCTF to move hundreds of miles each day, to attack in unexpected places, meant the Japanese often struggled to counterattack. It was only at times when the fast carriers were tied to an objective that the Japanese were able to mount large scale raids to attack our fleet. The most obvious example of this is the horrible attrition imposed on the fleet while supporting operations at Okinawa.
After the Vietnam War, the Navy looked at what it might be required to do in a World War III scenario versus the Soviet Union. The primary task was to secure the sea lanes to Europe. The primary Soviet threats to the sea lanes were submarines, and long range land based bombers armed with cruise missiles. We’ll leave the discussion of the submarine threat to another time, but the Navy realized it would be called upon to stop the long range bomber threat, both as a threat to merchant shipping, and to the carrier forces themselves. Soviet long range aviation had a much longer strike range than the organic airwing of carriers. To charge in and raid the Soviet bomber bases, the carriers would have to be able to avoid detection. And so they spent a fair portion of the coldest days of the Cold War learning to do just that.
The force transits to its objective area in complete electronic silence. Deceptive formations are used dispersed over a broad area to ensure any detection system does not see the classic “bullseye” formation made famous in countless Public Affairs shots and never used in operations. Broad surveillance systems are known so any detection method is countered either by denying sensor information, misleading, or providing expected results consistent with something else. For example, ESM systems rely on active emissions from radars or communication systems. So nothing is radiated. Overhead systems are in known orbits, are predictable, and their sensing capabilities known. So the track is varied, weather is sought out to hide in when vulnerable, blending into sea lanes (while staying out of visual detection range of ships) and such techniques. Deceptive lighting is used at night so that the obvious “blacked out warship” is instead thought to be a merchant or cruise liner. Surface search radar identical to commercial ones are used. Turn count masking is used by the ships. Aircraft maintenance on the CV and other helo equipped ships is limited to prevent transmissions.
In NORPAC 82 using these and other tactics the CV force operated close enough to support each other, but far enough and randomly dispersed to avoid identification by anyone. One night in bad weather a man went overboard when the ship was within 200nm of a Soviet airfield in the Kuril Island chain. Despite launch of helicopters and active search methods by several ships in the successful SAR, including clear voice UHF transmissions, the force is not detected because no Soviet asset was above the radar horizon. No overhead system was cued. The force continued on.
The Chinese have spent the last 20 years developing anti-access/area-denial tactics, techniques, and procedures. And to be sure, any operations against China would be significantly different than operations in the northern reaches of the Atlantic or Pacific.
But to blithely dismiss the ability of a carrier strike group to avoid detection (or at a minimum, to avoid being recognized as a carrier group) is to overlook the long history of carrier groups successfully approaching enemy shores.