Ship loads drink that's promoted strength (5)
I believe the answer is:
asset
'strength' is the definition.
(I've seen this before)
'ship loads drink that's promoted' is the wordplay.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'loads' becomes 'tea' (I can't explain this - if you can you should believe this answer much more).
'drink' indicates putting letters inside.
'that's promoted' is a reversal indicator (going up, in a down clue).
'ss' placed inside 'tea' is 'tessa'.
'tessa' back-to-front is 'ASSET'.
Can you help me to learn more?
(Other definitions for asset that I've seen before include "Beneficial thing" , "Item conferring advantage" , "- - -stripper" , "Valuable item" , "Seats (anag.)" .)