Race to the source

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Across
  1. 3. Water water everywhere but not a drop to drink
  2. 8. Fresh water hole
  3. 10. Signs for ships
  4. 11. Boat parker
  5. 12. The largest living structure
Down
  1. 1. Swimming mammal
  2. 2. They watch the line between land and sea
  3. 4. They like it salty
  4. 5. Produced in a kiln
  5. 6. Like ketchup and chili, but spelt differently
  6. 7. Growing first but where they're found is out of sight and underground
  7. 9. Sailor saver