Teaches in fashion: it’s boring in the main (9)

I believe the answer is:

drillship

I'm a little stuck... Click here to teach me more about this clue!

'boring in the main' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'teaches in fashion' is the wordplay.
'teaches' becomes 'drills' (drilling is a kind of teaching).
'in fashion' becomes 'hip' (I've seen this in another clue).
'drills'+'hip'='DRILLSHIP'

'it's' is the link.

Can you help me to learn more?

I've seen this clue in The Independent.

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