Loads volcanic rock aboard steamer (6)
I believe the answer is:
stuffs
'loads' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Perhaps you can see a link between them that I don't see?
'volcanic rock aboard steamer' is the wordplay.
'volcanic rock' becomes 'tuff' (I've seen this in another clue).
'aboard' means one lot of letters goes inside another.
'steamer' becomes 'SS' (prefix in ship names eg SS Great Britain).
'tuff' placed inside 'ss' is 'STUFFS'.
Can you help me to learn more?
(Another definition for stuffs that I've seen is " Crams".)