Article in seagoing vessel having one dimension (6)

I believe the answer is:

linear

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'having one dimension' is the definition.
I can't tell whether this defines the answer.

'article in seagoing vessel' is the wordplay.
'article' becomes 'a' (English indefinite article).
'in' is an insertion indicator.
'seagoing vessel' becomes 'liner'.
'a' inserted inside 'liner' is 'LINEAR'.

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(Other definitions for linear that I've seen before include "Straight; sequential" , "One-dimensional" , "Arranged in straight fashion" , "Long and narrow, of one dimension" , "Nailer (anag.)" .)

I've seen this clue in The Times.

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