Collect cockney's meat with a steamship (5)
I believe the answer is:
amass
'collect' is the definition.
(I know that collect is a more specific form of amass)
'cockney's meat with a steamship' is the wordplay.
'cockney's meat' becomes ''am' ('ham' - ham is a kind of meat - said with a cockney accent, dropping the 'H').
'with' is a charade indicator (letters next to each other).
'steamship' becomes 'ss' (nautical abbreviation).
'am'+'a'+'ss'='AMASS'
(Other definitions for amass that I've seen before include "Gather together, pile up" , "Collect, hoard" , "Stock up on" , "Accumulate, pile up" , "Get together" .)