The most common and most likely answer to this crossword clue is the 9 letter word AMIDSHIPS
I've seen this crossword clue in The Guardian
A
M
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D
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H
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Buddy explains!
The straight part
We know that "halfway to 23" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case halfway to 23 = amidships.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 AMIDSHIPS mean?
AMIDSHIPS adverb- In the middle of a ship, either longitudinally or laterally.
- Usually in the line of the keel, but sometimes halfway between bow and stern; often contracted to “midships.” (FM 55-501).
- On the flank, at a vulnerable place.
- A helm order, normally shortened to midships!, to centre the helm in the line of the keel.