Left port fully loaded (5)
I believe the answer is:
laden
'fully loaded' is the definition.
(I've seen this in another clue)
'left port' is the wordplay.
'left' becomes 'l' (common abbreviation).
'port' becomes 'aden' (port in Yemen).
'l'+'aden'='LADEN'
(Other definitions for laden that I've seen before include "Loaded with cargo or burden" , "full cargo ship" , "bearing burden" , "Like cargo boat" , "cargo aboard" .)