With no hesitation sea captains will see Poles on ships (9)

'poles on ships' is the definition.
'mainmasts' can be an answer for 'poles' (mainmast is a kind of pole). I am not certain of the 'on ships' bit.

'with no hesitation sea captains will' is the wordplay.
'with no' indicates named letters should be taken away.
'hesitation' becomes 'er' (sound used when hesitating).
'sea' becomes 'marine' (I've seen this before).
'captains will' becomes 'masts' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'marine' with 'er' taken out is 'main'.
'main'+'masts'='MAINMASTS'

'see' is the link.

Can you help me to learn more?