Power boat race starting off turning east of waterfront (7)
I believe the answer is:
wattage
'power' is the definition.
(wattage is a kind of power)
'boat race starting off turning east of waterfront' is the wordplay.
'boat race' becomes 'regatta' (I've seen this in another clue).
'starting off' means to remove the first letter (the starting letter is removed).
'turning' shows that the letters should be reversed in order.
'east of' means one lot of letters go next to another (some letters go to the right of others).
'waterfront' becomes 'w' (this could be a standard abbreviation which I don't know about).
'regatta' with its first letter taken away is 'egatta'.
'egatta' reversed gives 'attage'.
'attage' after 'w' is 'WATTAGE'.
Can you help me to learn more?
(Other definitions for wattage that I've seen before include "Electrical power rating" , "Amount of electrical power" , "Light bulb power rating" .)