The most common and most likely answer to this crossword clue is the 4 plus 2 plus 3 plus 5 letter word DEAD IN THE WATER
I've seen this crossword clue in The Guardian
D
E
A
D
I
N
T
H
E
W
A
T
E
R
More clues leading to the result DEAD IN THE WATER
Buddy explains!
The straight part
We know that "Like the Ancient Mariner’s ship" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case like the ancient mariner’s ship = dead in the water.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.