Was fast and furious: the sea being rough (4,5)
I believe the answer is:
made haste
'was fast' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'furious the sea being rough' is the wordplay.
'furious' becomes 'mad' (I've seen this before).
'being rough' indicates anagramming the letters (a rough or broken ordering of the letters).
'the'+'sea'='thesea'
'thesea' with letters rearranged gives 'ehaste'.
'mad'+'ehaste'='MADE HASTE'
'and' is the link.
Can you help me to learn more?
(Other definitions for made haste that I've seen before include "rushed" , "Hurried" , "progressed rapidly" .)