Underwater craft about to move south (1-5)

I believe the answer is:

u-boats

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'underwater craft about to move south' is the definition.
I can't judge whether this defines the answer.

'about to move south' is the wordplay.
'to move' indicates anagramming the letters.
'south' becomes 'S' (synonyms).
'about' is an anagram of 'uboat'.
'uboat'+'s'='U-BOATS'

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(Other definitions for u-boats that I've seen before include "Submersible warships" , "German subs" , "Submersible ships of WW2" , "German submarines of second World War" , "German submarines in WW2" .)

I've seen this clue in The Sun.

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