Submarine about to disintegrate (1-4)

I believe the answer is:

u-boat

'submarine' is the definition.
(I know that submarine can be written as U-boat)

'about to disintegrate' is the wordplay.
'to disintegrate' indicates anagramming the letters (I've seen 'disintegrated' mean this).
'about' with letters rearranged gives 'U-BOAT'.

(Other definitions for u-boat that I've seen before include "About (anag)" , "Sea vessel" , "German World War One or World War Two submarine" , "German wartime submarine" , "Submersible warship of WWII" .)

I've seen this clue in The Sun and The Times.

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