Why a naval drone becomes more than a cheap civilian drone

How could small civilian drones affect future naval missions such as boarding, scanning, and search and rescue?

They could help, but military requirements for security, endurance, and reliability make them much more capable and costly than civilian models.

Small drones could help with pre-boarding inspection, scanning, and search and rescue. A naval force, however, must assume that a suspect vessel may jam the link or try to seize control of the aircraft. Secure communications, greater endurance, and reliable operation in wind and other difficult conditions add weight and require more powerful propulsion. Unlike a building surveyor, a boarding team may make a life-or-death decision from the drone's picture, so failure cannot be treated as a minor inconvenience. Those requirements explain why the military version becomes larger and far more expensive than the superficially similar civilian product.