It has a way of being covered at sea (5)
I believe the answer is:
hatch
'it has a way of being covered' is the definition.
The definition suggests a singular noun which matches the answer.
'at sea' is the wordplay.
I cannot really see how this works, but
'at' is within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for hatch that I've seen before include "Breed" , "Deck opening; (egg) open" , "Incubate - plan" , "Come up with" , "Incubate - opening" .)