A big blow to our sailors over a party (7)

I believe the answer is:

tornado

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'a big blow to our sailors' is the definition.
I can't judge whether this defines the answer.

'over a party' is the wordplay.
'over' becomes 'torn' (I can't explain this - if you can you should give a lot more credence to this answer).
'party' becomes 'do' (do is a kind of party).
'torn'+'a'+'do'='TORNADO'

Can you help me to learn more?

(Other definitions for tornado that I've seen before include "RAF fighter; whirlwind" , "Hurricane" , "Violent wind storm" , "Windy hazard" , "Violent twister" .)

I've seen this clue in The Times.

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