Leaders of yesteryear approach captain helming tourist vessel (5)
I believe the answer is:
yacht
'vessel' is the definition.
(yacht is a kind of vessel)
'leaders of yesteryear approach captain helming tourist' is the wordplay.
'leaders of' says to take the initial letters.
The first letters of 'yesteryear approach captain helming tourist' is 'YACHT'.
(Other definitions for yacht that I've seen before include "Sailing boat" , "Sailing or motor vessel for cruising or racing" , "Type of boat" , "Light sailing vessel" , "Pleasure craft" .)