Marine protection from rapid gush at sea (5-4)

I believe the answer is:

guard-ship

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'marine protection' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I don't see?

'rapid gush at sea' is the wordplay.
'at sea' indicates anagramming the letters.
'rapid'+'gush'='rapidgush'
'rapidgush' anagrammed gives 'GUARD-SHIP'.

'from' is the link.

Can you help me to learn more?

I've seen this clue in The Independent.

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