Technology companies and shipyards are vying for attention as the US unmanned navy grows in size and sophistication.No too long ago, US Navy Secretary John Phelan said: “If the last few years of conflict have taught us anything, it is that we will not win the wars of the future with the platforms of the past.” The nation’s ability to deter future conflict or to prevail, if necessary, will benefit from high quantities of low-cost air, surface and subsea unmanned systems. These…