Ark vacated after big ruminant capsizes boat (5)
I believe the answer is:
kayak
'boat' is the definition.
(I know that boat is the is a more specific form of the action of kayak.)
'ark vacated after big ruminant capsizes' is the wordplay.
'vacated' suggests removing the centre (internal letters vacate the word).
'after' is a charade indicator (letters next to each other).
'big ruminant' becomes 'yak' (yak is a kind of ruminant. I am not sure about the 'big' bit.).
'capsizes' says the letters should be written in reverse (letters flip over).
'ark' with its centre removed is 'ak'.
'yak' written backwards gives 'kay'.
'ak' put after 'kay' is 'KAYAK'.
Can you help me to learn more?
(Other definitions for kayak that I've seen before include "A small covered canoe" , "Type of canoe" , "Inuit's light canoe" , "Arctic canoe" , "Palindromic canoe used by eskimos" .)