Question

Q15. 'Water, water, every where.... Nor any drop to drink.' When does the ancient Mariner make this statement? What does it show about the condition of the sailors? ​

Answer 1

This line was used to indicate that when the sailors were stranded in the middle of the becalmed sea and were thirsty, there was sea water all around them, but the irony was they couldn't drink a single drop because that water was useless to them.

So this statement indicates the 'irony' of something that is in front of them, but is completely worthless to them.

By the way, never forget this statement, it's a very good phrase.