Craft departs to enter rippling lagoon (7)
I believe the answer is:
gondola
'craft' is the definition.
(gondola is a kind of craft)
'departs to enter rippling lagoon' is the wordplay.
'departs' becomes 'd' (common abbreviation e.g. train timetables).
'to enter' indicates putting letters inside.
'rippling' indicates anagramming the letters.
'lagoon' with letters rearranged gives 'gonola'.
'd' going within 'gonola' is 'GONDOLA'.
(Other definitions for gondola that I've seen before include "Boats on the canals of Venice" , "Cabin suspended from an airship" , "Venetian taxi" , "Boat on Venetian canals" , "Compartment suspended from an airship" .)