Gathering to have silver initially loaded on board famous ship (6)
I believe the answer is:
beagle
'famous ship' is the definition.
(ship Charles Darwin travelled on)
'gathering to have silver initially loaded' is the wordplay.
'gathering' becomes 'bee' (bee is a kind of gathering).
'to have' is an insertion indicator.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'initially' suggests taking the first letters.
The first letter of 'loaded' is 'l'.
'ag'+'l'='agl'
'bee' enclosing 'agl' is 'BEAGLE'.
'on board' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for beagle that I've seen before include "5 [MANS BEST FRIEND]" , "Small hunting dog" , "Small short-legged hound" , "Hunting hound" , "HMS - was Darwin's ship; hunting dog" .)