Rude about ships force (6)
I believe the answer is:
duress
'force' is the definition.
(I know that duress is a type of force)
'rude about ships' is the wordplay.
'about' is an anagram indicator.
'ships' becomes 'ss' (I can't explain this - if you can you should give a lot more credence to this answer).
'rude' with letters rearranged gives 'dure'.
'dure'+'ss'='DURESS'
Can you help me to learn more?
(Other definitions for duress that I've seen before include "Constraint, force" , "Use of force or threats, often vile" , "Coercion, compulsion" , "Hardship" , "Coercion, pressure" .)