Angry exclamation used by sailor folk (9)

'angry exclamation' is the definition.
The definition suggests a singular noun which matches the answer.

'by sailor folk' is the wordplay.
'by' is a charade indicator (letters next to each other).
'sailor' becomes 'tar' (term for a sailor).
'folk' becomes 'nation' (I can't explain this - if you can you should believe this answer much more).
'tar' put next to 'nation' is 'TARNATION'.

'used' acts as a link.

Can you help me to learn more?