Boat carrying less cargo? (7)
I believe the answer is:
lighter
I believe this clue is a double definition.
'boat' is the first definition.
(I know that lighter is a type of boat)
'carrying less cargo?' is the second definition.
(I've seen this before)
(Other definitions for lighter that I've seen before include "Cargo barge; smoker's accessory" , "less tonnage" , "Device for igniting cigarette" , "Barge; igniter" , "Barge (more likely to float?)" .)