Is brave sailors a proper noun or common noun'?

The term 'brave sailors' is a noun phrase; the adjective 'brave' describing the plural, common noun 'sailors'.

The noun 'sailors' is a Word for people who sail boats or people who are crew members on a commercial or naval ship.

A proper noun is the name of a specific person, place, or thing.

A proper noun for the common noun 'sailors' is the names of the sailors.