Test puzzle

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Across
  1. 3. Opposite of flow
  2. 4. Sailor's drink
  3. 7. Missing fish
  4. 9. Destructive wave
  5. 12. Right?
  6. 13. Large mammal
  7. 15. Roman god of the sea
  8. 17. Pembrokeshire beach. North or South?
  9. 19. Cause a stir
Down
  1. 1. Nautical
  2. 2. Magnifier
  3. 5. Fish friend
  4. 6. Speed measurement
  5. 8. Home of the last invasion
  6. 10. Whaling HQ
  7. 11. Salt water
  8. 14. Englishman
  9. 16. Pequod captain
  10. 17. Crew member
  11. 18. Spinach lover