The most common and most likely answer to this crossword clue is the 9 letter word CASTAWAYS
I've seen this crossword clue in The Daily Telegraph
C
A
S
T
A
W
A
Y
S
More clues leading to the result CASTAWAYS
Buddy explains!

The straight part
We know that "they may be conveying a cry for help" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they may be conveying a cry for help = castaways.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 CASTAWAYS mean?
CASTAWAYS noun- A shipwrecked sailor.
- A discarded person or thing.
- An outcast; someone cast out of a group or society.