The most common and most likely answer to this crossword clue is the 9 letter word SCHOONERS
I've seen this crossword clue in The Daily Telegraph
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More clues leading to the result SCHOONERS
Buddy explains!
The straight part
We know that "Ships/in which sherry may be served" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ships/in which sherry may be served = schooners.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 SCHOONERS mean?
SCHOONERS noun- A sailing ship with two or more masts, all with fore-and-aft sails; if two masted, having a foremast and a mainmast.
- A glass of beer, of a size which varies between states (Wikipedia).
- A large goblet or drinking glass, used for lager or ale (Wikipedia).
- A covered wagon used by emigrants.