Young creatures found aboard mythical vessel (6)
I believe the answer is:
calves
'young creatures' is the definition.
'calves' can be an answer for 'creatures' (calf is a kind of creature). I am not sure about the 'young' bit.
'found aboard mythical vessel' is the wordplay.
'found' indicates a hidden word.
'CALVES' is hidden within 'aboard mythical vessel'.
Can you help me to learn more?
(Other definitions for calves that I've seen before include "Young farm animals" , "Young domestic cattle" , "Young cows" , "features of legs" , "Small and neat" .)