Log wave as the biggest ever (6-7)
I believe the answer is:
record-breaker
'the biggest ever' is the definition.
I can't judge whether this definition defines the answer.
'log wave' is the wordplay.
'log' becomes 'record' (I've seen this in another clue).
'wave' becomes 'breaker' (breaker is a kind of wave).
'record'+'breaker'='RECORD-BREAKER'
'as' acts as a link.
Can you help me to learn more?
(Other definitions for record-breaker that I've seen before include "Best-ever performance achiever" , "Person having surpassed the previous best" .)