Barfleur's fog becomes an analogy for missile identification

Even with friend-or-foe identification systems, a radar-guided missile could be drawn toward friendly ships if opposing formations were close enough for their returns to be confused or spoofed. The distance counted as close depends on the weapon and its speed; for a hypersonic missile, it could be surprisingly large. In Barfleur's fog, crews had to approach closely enough to identify their targets visually. Uncertain recognition limited their ability to fire confidently at the intended enemy.