In a then-classified 2002 war game called Millennium Challenge, the Red Team, commanded by Lt. Gen. Paul Van Riper, sent waves of small boats, some loaded with explosives, to overwhelm the defenses of the Blue Team, representing the U.S. Navy. The results were grim. Blue Team lost 16 major warships—including a carrier. But the game was immediately restarted and Blue Team was eventually declared the winner.

Van Riper complained at the time that lessons were not being learned. Swarming speedboats represent a major threat to Navy aircraft carrier groups. Small boats are dangerous because they can emerge without warning from behind islands or other features, and weapons systems are designed to handle fewer, larger opponents, so carriers and other large vessels might be swamped before they can deal with the threat.

Today the Navy appears to be taking the threat more seriously. And existing defense technologies could be combined to create a defensive shield to detect and destroy boat swarms from a safe distance. The latest proposal involves an all-seeing eye in the sky that can pick out small boats at a distance and see over obstacles.

Raytheon's JLENS (Joint Land Attack Cruise Missile Defense Elevated Netted Sensor) is a blimp-based radar system that provides 360-degree, 24/7 coverage. The unmanned blimps or aerostats are 77 yards long. Each JLENS system, or orbit, has two of them, one with surveillance radar and one with a fire-control radar.

As the name suggests, JLENS was developed for defense against cruise missiles and can track aircraft. But it can also handle surface targets. This June JLENS went through a series of exercises on the Great Salt Lake to test its capability against swarming boats. A number of fast boats carried out tactical maneuvers at both high and low speeds, simulating an aggressive boat swarm. JLENS simultaneously detected and tracked the boats from over a hundred miles away.