Father wrapping large boat in insulated coat (5)
I believe the answer is:
'insulated coat' is the definition.
(type of winter coat)
'father wrapping large boat' is the wordplay.
'father' becomes 'pa' (pa can mean dad or father).
'wrapping' indicates putting letters inside.
'large boat' becomes 'ark' (as in Noah's ark).
'pa' enclosing 'ark' is 'PARKA'.
'in' is the link.
(Other definitions for parka that I've seen before include "Weatherproof jacket with hood" , "Windproof jacket" , "Kind of heavy jacket" , "jacket for cold weather" , "Hooded warm jacket" .)