The most common and most likely answer to this crossword clue is the 10 letter word BRIGANTINE
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More clues leading to the result BRIGANTINE
- Be training around a ship
- Strange training in empty barge vessel
- Soldier turning to another in sea ship
- Giant waves in the sea for boat
- Be providing protection for mobile training vessel
- Hercules, say, sending one aloft in sea vessel
- Ship makes giant wave in seawater
- Vessel with awful tang I dumped in sea
- Boat train being derailed
- I grin and bear it
Buddy explains!

The straight part
We know that "pirate ship" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case pirate ship = brigantine.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 BRIGANTINE mean?
BRIGANTINE noun- A two-masted vessel, square-rigged on the foremast, but fore-and-aft-rigged mainsail with a square-rig above it on the mainmast.
- A coat of armor for the body, consisting of scales or plates, sometimes overlapping each other, generally of metal, and sewn to linen or other material.