The most common and most likely answer to this crossword clue is the 7 letter word SURFING
I've seen this crossword clue in The Guardian
S
U
R
F
I
N
G
More clues leading to the result SURFING
Buddy explains!

The straight part
We know that "Going over the water/Channel-hopping" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case going over the water/channel-hopping = surfing.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SURFING mean?
SURFING verb- To ride a wave, usually on a surfboard.
- To browse the Internet, television, etc.
- The pastime or sport of riding surf on a surfboard.
- The activity of browsing the Internet.