### Clue: Mid-Atlantic crossing perhaps, rolling to some extent (4,4,4)
### Answer: HALF SEAS OVER 
 ### Explanation: Definition: rolling to some extent
 Cryptic defn: In the middle of an Atlantic Ocean crossing, you'd have gone over half of the seas.
Answer: A British term for being drunk, and to some extent rolling(slang for swaying or staggering, as in "rolling drunk").