Slow and clumsy boat, but capsized (3)
I believe the answer is:
tub
'slow and clumsy boat' is the definition.
I can't judge whether this definition defines the answer.
'but capsized' is the wordplay.
'capsized' is a reversal indicator (in a down clue, the word turns upside down).
'but' written backwards gives 'TUB'.
Can you help me to learn more?
(Other definitions for tub that I've seen before include "Container for yogurt, ice-cream" , "Open container, for liquid say" , "Unwieldy vessel" , "Wooden bath or slow boat" , "Bath; ice cream container" .)