This tactic only really works during peace time. The main strategy relies on the fact that the US (or whoever) isn't willing to shoot on sight. The swarm might

This tactic only really works during peace time. The main strategy relies on the fact that the US (or whoever) isn't willing to shoot on sight. The swarm might well be able to get a good shot or two in but that would be the end of it. Once a war is going on the you can move to a much more aggressive strategy. The US can just declare that any boats within a certain region are subject to summary attack and all shipping should steer clear. Attack aircraft can start sinking these small boats as soon as they leave harbour (or most likely cruise missiles blow them up at anchor).