Crossword Puzzle 4

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Across
  1. 2. submarine, a submersible navy vessel used to seek and destroy other submarines and surface vessels, as well as to launch missiles ashore
  2. 4. water environment, an area of water where the water level is not deep, preventing the operation of some ships
  3. 5. destruction, an order to destroy papers or information
  4. 6. valve, a manual control used to open a sprinkler system
  5. 7. missile, a surface-air projectile weapon that can be mounted on ships to attack coming aircraft
  6. 8. security, a set of practices designed to prevent attacks from outside forces on a ship or naval area
  7. 9. security, a set of practices designed to protect the confidentiality of Naval operations
Down
  1. 1. someone whose aim is to destroy or disrupt a military’s activities
  2. 3. a device that contains a gyroscope rotor and indicates true north
  3. 6. navigation, a navigation method based on stars