Traditionally, to sail “yar” means to sail true. In piratical terms, though, it’s a romanticized shout among pirates that not only identify themselves in language, but also grab attention and either give agreement or a warning.
I’m thinking we as pirates, identifying one another, are shouting truth to dissolve the villainy of the out-of-touch and insane “authority.” Keep pelting them with the sea of salt. Have you ever seen a slug shrivel? We’ve got plenty of ocean and our truth ship sails YARR!