ABOARD A U.S. MILITARY AIRCRAFT OVER KODIAK ISLAND, Alaska — To the uninitiated, this felt like insanity. From an altitude of 8,000 ft, six Navy SEALs had been about to parachute into Marmot Bay, the place the water temperature was simply barely above freezing.

Their inflatable boat went first, rumbling down the ramp of this MC-130 transport aircraft earlier than snapping out the again. These stout, nondescript airframes had been engineered particularly to allow the “low visibility” operations which can be a trademark of the U.S. army’s clandestine forces. As one of many SEALs roused from a nap, the aircraft leveled off.