Boat loaded with most of new basket (6)
I believe the answer is:
punnet
'basket' is the definition.
(punnet is a kind of basket)
'boat loaded with most of new' is the wordplay.
'boat' becomes 'punt' (I've seen this before).
'loaded with' means one lot of letters goes inside another.
'most of' means to remove the last letter.
'new' with its last letter taken off is 'ne'.
'punt' placed around 'ne' is 'PUNNET'.
(Other definitions for punnet that I've seen before include "Shallow fruit basket" , "Small basket for 13 Across (6)" , "Small light basket, for strawberries say" , "Source of fruit" , "Fruit 18 Down" .)