The barrier had never been expected to halt more than half of the attacking submarines, however, and those that succeeded in slipping through would have to be handled differently. The deep ocean basins were simply too wide and too deep—the average depth was over two miles—to be littered with sensors as the shallow choke points were. This was a fact that cut both ways. The NATO mission would be to maintain the Atlantic Bridge and continue transoceanic trade, and the obvious Soviet mission would be to interdict this trade. Submarines would have to spread out over the vast ocean to cover the many possible convoy routes. NATO strategy behind the SOSUS barriers, then, was to assemble large convoys, each ringed with destroyers, helicopters, and fixed-wing aircraft. The escorts would try to establish a protective bubble about a hundred miles across. Enemy submarines would not be able to exist within that bubble; if in it they would be hunted down and killed—or merely driven off long enough for the convoy to speed past. Thus while SOSUS was designed to neutralize a huge, fixed expanse of sea, deep-basin strategy was founded on mobility, a moving zone of protection for the vital North Atlantic shipping.

This was an altogether sensible strategy, but one that could not be tested under realistic conditions, and, unfortunately, one that was largely useless at the moment. With all of the Soviet Alfas and Victors already on the coast, and the last of the Charlies, Echoes, and Novembers just arriving on their stations, the master screen Commander Quentin was staring at was no longer filled with discrete little red dots but rather with large circles. Each dot or circle designated the position of a Soviet submarine. A circle respresented an estimated position, calculated from the speed with which a sub could move without giving off enough noise to be localized by the many sensors being employed. Some circles were ten miles across, some as much as fifty; an area anywhere from seventy-eight to two thousand square miles had to be searched if the submarine were again to be pinned down. And there were just too damned many of the boats.