Log container crossing a harbour (9)
I believe the answer is:
entertain
'harbour' is the definition.
('entertain' can be a synonym of 'harbour')
'log container crossing a' is the wordplay.
'log' becomes 'enter' (I've seen this before).
'container' becomes 'tin' (tin is a kind of container**).
'crossing' means one lot of letters goes inside another.
'tin' going around 'a' is 'tain'.
'enter'+'tain'='ENTERTAIN'
(Other definitions for entertain that I've seen before include "what the party host will do" , "Play host to" , "Amuse or take into consideration" , "Amuse - give hospitality" , "cheer" .)