Wave over ship in thrilling ride (6-7)
I believe the answer is:
Here is my best explanation:
'thrilling ride' is the definition.
'wave over ship' is the wordplay.
'wave' becomes 'roller' (I've seen this before).
'over' says to put letters next to each other.
'ship' becomes 'coaster' (coaster is a type of ship).
'in' acts as a link.
(Another definition for roller-coaster that I've seen is "Fairground ride".)