How does a nuclear supercarrier, escorts, aircraft, and submarines constitute to defend it, come to die in the hands of such a much smaller boat, which operates on batteries? A solution is to be found in a Cold War exercise simulation that remains in play due to its description of an ugly reality of undersea detection: the most vocalized assumption has a tendency to be followed through. A Canadian Oberon-class diesel-electric submarine was somehow able to penetrate the protective screen of USS Dwight D. Eisenhower during a NATO exercise in the early 1980s and was able to get into a position where it could effectively pretend to have launched a torpedo attack. The case of adjudication was as significant as the methodology; a U.S. Navy umpire tested the system and stated that the carrier was sunk.
It was not a cunning device that made the episode lasting, but physics which was taken advantage of by discipline. A battery-powered diesel electric boat eliminates much of the noise caused by machinery that is considered the constant activity of a nuclear submarine. Nuclear propulsion introduces speed and stamina, and it introduces a minimum acoustical footprint of systems that need to continue operating: coolant flow, turbines and related equipment. In the sea, vibration in the mechanical sense is transformed to sound-pressure waves; rotating devices have recognizable tones that vary depending on shaft speed, blade speed, and so can travel great distances being detected by hydrophones. The strength the Oberon had was that he could become nearly inert, slow, quiet, and patient, and the masking of the ocean would be done, as he sought the acoustic seams of the carrier group.
Those seams were not mystical blind spots rather than areas where the geometry of the screen and the acoustic conditions of the water, and search patterns of the defender, provided available loopholes. It is said that the Canadian crew received a training program that focused on the anti-submarine warfare as practiced by the defender, developing a sense of the search of the escorts and how the aircraft indicate the presence of the surface ships, and where the protective net is the weakest. On occasions when the Oberon detected a quiet spot around the carrier, under his protective attitude, he was not a sprinter. It waited.
The waiting game also pointed out a cultural trap in ASW; planning to respond to the most similar threat to the last large one. The U.S. carrier defences during the Cold War were influenced on the possibility of the lightning-fast deep-diving Soviet nuclear boats. Sense parameters, method of prosecution, and operator intuition had been towards picking up something which began to move fast and produced the typical sound of a nuclear propulsion station. The slow moving, low-acoustic characteristic of a small diesel-electric submarine did not fit into that mental model, and that discrepancy can provide sufficient time to force the recognition process before the attacker could arrive at a solution to fire.
The expanded Cold War history confirms the fact that this is still an issue of engineering rather than a trivia tale. After world war II, anti-submarine warfare became a top priority, and the substantial investment in sonar developments and wide area systems like the Sound Surveillance System (SOSUS), and deep cooperation among research institutions in improving the acoustic theory and processing power. Already, however, the ability differences appeared in unlikely locations, notably in the weapons-development programs, and the battle was a spendthrift game of silence efforts vs. improved detection.
What the Oberon incident finally proved was that the asymmetry inherent in the littorals and chokepoints: a defender could have more sensors, more platforms, and more power, and still fail to deal with a boat capable of reducing its signature and taking the pace of a slow approach. Diesel-electrics do not always operate quietly, they need recharging and without air-independent systems they eventually snorkel. And in the interval when they are underwater to the full on batteries, the sea may be the camouflage of the attacker and the cover group of stratified barriers may be driven to a search problem, which has neither one, true, solution.
