The most common and most likely answer to this crossword clue is the 8 letter word TOPSAILS
I've seen this crossword clue in Independent
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The straight part
We know that "Part of boat’s equipment" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case part of boat’s equipment = topsails.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 TOPSAILS mean?
TOPSAILS noun- A sail or either of the two sails rigged just above the course sail and supported by the topmast on a square-rigged sailing ship.
- In a fore-and-aft-rigged sailing boat, the sail that is set above the gaff at the top part of the mast.