The most common and most likely answer to this crossword clue is the 8 letter word LIFEBELT
I've seen this crossword clue in The Daily Telegraph
L
I
F
E
B
E
L
T
Buddy explains!
The straight part
We know that "If one has trouble crawling, one gets thrown out" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case if one has trouble crawling, one gets thrown out = lifebelt.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 LIFEBELT mean?
LIFEBELT noun- A buoyant ring carried on board ships that can be thrown to someone in the water in an emergency to keep themselves afloat.