I don't speak a word of Japanese, so forgive me if the Japanese names are crappy.

Privatyke:
Japanese: Ikaizoku - From "ika" (squid) and "kaizoku" (pirate).
French: Poulpirate - From "poulpe" (octopus) and "pirate".

Arghonaut:
Japanese: Takurohige - From "tako" (octopus) and "Kurohige" (Blackbeard).
French: Capoulpitain - From "poulpe" and "capitaine" (captain), trimmed to fit the 12-character limit. I laughed my head off at this one, it's just as stereotypically bad as some of the real French names.