Contend it's something you see on a ship (4)
I believe the answer is:
spar
'contend' is the definition.
(I know that spar is a kind of contend)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for spar that I've seen before include "Box for practice" , "Mineral; plane's wing beam" , "Box - girder" , "possibly rigged" , "Round pole to support sail" .)