Sailor, returning to vessel with keg, sounds low (4,4)
I believe the answer is:
bass drum
'sounds low' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'sailor returning to vessel with keg' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'returning' says the letters should be written in reverse.
'to vessel' becomes 'SS' (prefix in ship names eg SS Great Britain).
'with' says to put letters next to each other.
'keg' becomes 'drum' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ab' in reverse letter order is 'ba'.
'ba'+'ss'+'drum'='BASS DRUM'
Can you help me to learn more?
(Other definitions for bass drum that I've seen before include "Booming percussion instrument" , "Large percussion instrument" , "Big percussion instrument" , "Deep instrument" , "musical instrument" .)