“Sir, we have been hit.” The term has come to denote in a naval context a painful engineering fact: that an armed strike group of carriers can be expertly defended, and still attacked by an upward-caliber submarine which has made a single successful approach. The best-known case is an allied exercise in 2015, during which the French Rubis-class nuclear attack submarine Saphir made it through the screen around USS Theodore Roosevelt and simulated a shot at it, which counted as a kill. The worth of the episode was not the drama of a “sunk” supercarrier, but showing that overlaying sensors, helicopters, maritime patrol support and escort vessels are not a monolith. They are a game of probability and probabilities can be defeated.
That is why the Saphir drill has remained popular even though there were headlines made after the drills. The design of rubis-class boats goes back to the 1970s and was designed small by the standards of nuclear-submarine design, but could still achieve depths of over 300 meters and speeds of about 25 knots. That combination, small hull, undisturbed running, disciplined strategies, and good acoustics, was found to work sufficiently, and put a carrier at a simulated torpedo danger without having been observed. The U.S. Navy accepted the result and the Pentagon never publicly refuted it to make it an integral data point instead of a rumor.
There was also a pattern in the episode. During training, an equivalent of an “in-close” battle an equivalent of a Nimitz-class carrier was similarly defeated by the diesel-electric Gotland in 2004. Two years after that, a Chinese Song-class diesel-electric submersible appeared on the US Kitty Hawk radar at torpedo range, and surfaced in the killing field, a clear indication of a sign of imminent danger. What runs through all these events is not the nationality of the boats, but the repetitive skill of the submarines, whether nuclear or conventional, to find loopholes formed by the ocean conditions or the workload of managing contacts and the fact that attackers must be right once and defenders are right always.
The engineering dilemma is exacerbated by the modernization of submarine fleets as well as the diversification of their payload. A carrier has to be sunk to be strategically neutralized, even suppressing flight operations may be sufficient to disintegrate a task group purpose. The basis of such reasoning is why the conversation now revolves more around fast, long-range anti-ship weapons that advanced attack submarines can carry, such as the Yasen-class of Russia and its Zircon missile arsenal, one successful strike of which would be disastrous to sortie generation even when the ship does not sink.
The change that has occurred since those past “gotcha” situations is the way allies are transforming the hunt. Combination training taught by NATO now also challenges uncrewed vessels and autonomous systems including the incorporation of uncrewed surface vessels into large scale anti-submarine warfare exercises. The idea is coverage: increasing the number of sensors per node, increasing the duration per station, contributing to an overall picture that minimizes the chances of a submarine going through the needle.
Another fact highlighted by those drills is that geography does win the argument. NATO training in waters such as the Norwegian Sea and fjords has demonstrated that it is challenging to locate when submarines are able to utilize intricate landscape and acoustics to lose contact, despite forces applying ship sonars, helicopter-dipped sensors and aircraft sonobuoys. The environment does not make it difficult to track, it actually provides hiding spots which reward patient attackers.
The carrier is still a symbol of naval power projection, yet the aura of invulnerability has been swept away by emphasized, empirical evidence. The moral of the story of Saphir and of its analogies is not that carriers are dead. It is this that the threat in the sea is a design constraint-a constraint that determines the composition of the escorts, air tasking, sensor fusion, autonomy and the degree to which any carrier can safely navigate in contested littoral waters without acknowledging that a silent submarine might be already within the ring.
