Craft in East River capsized (5)
I believe the answer is:
trade
'craft' is the definition.
(I know that craft can be written as trade)
'east river capsized' is the wordplay.
'east' becomes 'e' (abbreviation).
'river' becomes 'dart' (River Dart in Devon).
'capsized' shows that the letters should be reversed in order (in a down clue, the word turns upside down).
'e'+'dart'='edart'
'edart' back-to-front is 'TRADE'.
'in' acts as a link.
(Other definitions for trade that I've seen before include "Commercial exchange of goods and services" , "Personal occupation" , "Customers" , "Commercial dealings" , "Calling" .)