Shortened reddish brown water carrier that's dilapidated and found in the sea (4,6)
I believe the answer is:
rust bucket
'sea' is the definition.
Both the definition and answer are singular nouns.
Maybe they are linked in a way I don't understand?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for rust bucket that I've seen before include "unroadworthy vehicle?" , "In old car" , "one, hardly roadworthy" .)