Over the whole past century, America's Silent Service has succeeded because of two constants. One is the greatness of the men who crew the boats in each generation. The other is the use of torpedoes (“fish”) as one of any attack sub's key armaments. Torpedoes, like people, pass through generations as decades pass. The smartest fish in the sea, today and tomorrow, is unquestionably the U.S. Submarine Force's brand-new Mod 7 of the Mark 48 Improved Advanced Capability (ADCAP) heavyweight, wire-guided torpedo.

But first, let's look at the alleged competition.

Lately there's been a brouhaha over the Russian 300-knot rocket propelled torpedo, the Shkval. Variants are now in the hands of China and Iran. Against a surface ship, a Shkval could be a formidable weapon. But against a U.S. Navy sub, these ultra-fast torpedoes don't really cut it. The basic design is a throwback to the late 1960s, when the Soviet weapons were nuclear armed. As such, Shkvals lacked any target homing sensors in the modern context. Recent attempts by the Kremlin to introduce a conventionally armed, and properly guided, updated mod of the Shkval face serious engineering and tactical obstacles. For homing sonar to work, the Shkval must slow down to regular torpedo speeds, making it vulnerable to standard U.S. submarine countermeasures, evasive maneuvers, and the coming miniaturized ATT -- the anti-torpedo torpedo, for which working test models already exist. Worse, the shape of a rocket torpedo, needed to achieve its “supercavitating” underwater high speed, is poorly suited for mounting sonar suites; the Shkval is a long cone which comes to a small and sharp point. Its own velocity blinds the Shkval, making it in practice a pretty dumb weapon.

Now let's check out the Mark 48 Mod 7. Its nose is a sizeable acoustically-transparent window, behind which are active and passive sonars of remarkable sophistication. The latest improvements to the sonars allow a much wider frequency range for simultaneously taking in broadband and tonals that give away a lurking or fleeing targeted enemy sub, even a quiet diesel. Just as important, the Mod 7 has been given a whole new computer brain, to interpret those sonar inputs and make brilliant autonomous decisions while in the race to catch and kill its prey. This was done by moving to “open architecture software,” a fancy way of saying that it's easy to update the fish's programming in general, and quite simple to load in detailed instructions for a specific type of attack mission. Reportedly, a single crewman with a laptop and a connector cable could reconfigure a torpedo room full of Mod 7s in barely an hour. One available configuration of crucial interest indeed is a littoral-optimized combination of sonar signal processors and artificial intelligence. The Mod 7 is still wire-guided, except now the wire is a fiber optic cable, allowing a quantum leap in bandwidth (data rate) for communication between weapons techs on the parent sub and their units in the water.

All this goes to make the latest generation Mark 48 by far the smartest “fish” anywhere in the sea.