The most common and most likely answer to this crossword clue is the 9 letter word SHIPMATES
I've seen this crossword clue in The Times
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More clues leading to the result SHIPMATES
Buddy explains!

The straight part
We know that "Fellows moving around in steamship?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fellows moving around in steamship? = shipmates.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 SHIPMATES mean?
SHIPMATES noun- A fellow sailor serving on the same ship as another.
- Any sailor (when used as a form of address by a sailor).