Crossword Genius

Restroom at sea, hearty! (10)

Ross

I believe the answer is:

headstrong

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

'restroom' is the definition.
I can't tell whether this definition defines the answer.

'sea hearty' is the wordplay.
'sea' becomes 'head' (I can't explain this - if you can you should give a lot more credence to this answer).
'hearty' becomes 'strong' (I've seen this in another clue).
'head'+'strong'='HEADSTRONG'

'at' acts as a link.

Can you help me to learn more?

(Other definitions for headstrong that I've seen before include "pig-headed" , "Wilful, determined" , "Stubborn" , "Obstinate" , "strong-willed" .)

I've seen this clue in the Sydney Morning Herald.
Want a hint initially instead of a full solution? Install my app