Possible Clues:

• Able to get to a half-century by way of water
• See 35-Down
• Ship's shortcut
• Is a half-century able to get dug
• See 51-Across
• Is a half century able to barge along it?
• Is a half-century able to barge along here?
• Water there for a dugout
• By way of water, Pa might get to the North to get Ma for one of such
• Able to start to have this dug for way of water