Get in after tying up the boat (6)
I believe the answer is:
obtain
'get' is the definition.
(obtaining is a kind of getting)
'in after tying up the boat' is the wordplay.
I cannot quite see how this works, but
'in' is within the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
The remaining letters 'oba' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for obtain that I've seen before include "Acquire or procure" , "'Get, acquire (6)'" , "Get or lay hold of" , "Take possession of" , "Come into possession of" .)