The most common and most likely answer to this crossword clue is the 8 letter word CAPSTANS
I've seen this crossword clue in Financial Times
C
A
P
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T
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More clues leading to the result CAPSTANS
Buddy explains!
The straight part
We know that "onboard winding devices" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case onboard winding devices = capstans.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 CAPSTANS mean?
CAPSTANS noun- A vertical cylindrical machine that revolves on a spindle, used to apply force to ropes, cables, etc. It is typically surmounted by a drumhead with sockets for levers used to turn it.
- A rotating spindle used to move recording tape through the mechanism of a tape recorder.