Possible Clues:

• One of those grand types coming into Dublin seen close to Rialto?
• Passage through Panama
• Place for a gondola
• Watercourse constructed initially from the bottom
• Barge in here perhaps with tin (aluminium)
• Channel that might be blocked by a ship
• Is a Liberal permitted to barge in here?
• Is Capone able to identify a watercourse?
• Note obsessive passage
• The Venetian way?