Earl's boat used a measuring device (9)

I believe the answer is:

astrolabe

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'device' is the definition.
(astrolabe is a kind of device)

'earl's boat used' is the wordplay.
'used' is an anagram indicator.
'earls'+'boat'='earlsboat'
'earlsboat' is an anagram of 'ASTROLABE'.

'a measuring' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.

Can you help me to learn more?

(Other definitions for astrolabe that I've seen before include "Old instrument for astronomical measurements" , "Old navigation instrument" , "Navigation aid" , "Navigational device" , "heavenly model" .)

I've seen this clue in The Daily Express.

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