Possible Clues:

• (Once) a ship's cheapest passenger accommodation
• Not a first class place for a beast as old as that
• Cheapest area on ship
• Accommodation always in arena
• Cheap accommodation for government?
• Convert ordinary language into code
• It's the cheapest way to go by sea
• Bullock takes time creating space on vessel
• Cheapest places, always ancient, seen in theatre
• Poet's always in coach, cheapest form of travel