Young man caught something floating in the sea (3)
I believe the answer is:
boy
'young' is the definition.
(young boy)
'man caught something floating in the sea' is the wordplay.
I cannot quite understand how this works, but
'man' could be 'bo' and 'bo' is found in the answer.
A single letter 'y' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for boy that I've seen before include "Young man" , "Son" , "Lad" , "Youth" , "Youthful male" .)