Related Clues:

• It may swell or have swells
• Porpoise place
• Azov is one
• Porpoise's place
• It's a great barrier
• School setting
• Nautical hazard
• Conclusion of "America the Beautiful"
• Coral or Sargasso
• Coral, for one
• Ross, for one
• Shark's place
• With 23-Across, Neptune, e.g.
• Davy Jones' locker
• Irish or Baltic, e.g.