I just released the Nautilus Pirates today along with small updates and tweaks to the Human Hive, Cybernetic Consciousness, and Lord's Believers. As always, the Unity Faction is synchronized with the latest updates as well and anyone subscribed to that mod can get the new faction through updating it from their mod-configuration menu or redownloading from OP at civfanatics.
The Nautilus Pirates were tricky because the lack of a strong naval game in Beyond Earth. They've probably taken the most radical change from their original interpretation and have a focus on early game scouting and exploration. I took particular inspiration from this passage in the GURPS Alpha Centauri supplement:
Among themselves, the Nautilus Pirates admire adventurism. The ideal Pirate sets high goals for himself, pursues them by any means necessary, and attains them with style and panache. The tales of such accomplishments play an important role in faction society. The Pirates' preferred art form is the story, either set down in print or told over beer in a public place. They hold most other forms of art in contempt, but their narrative literature is the best on Planet.
I ran with that and rather than focusing on the Pirate's original naval superiority, I decided to make them rowdy adventurers. They field upgraded explorers who are better in nearly every way and additionally can enter territory without open borders, pillage with no movement costs, and capture enemy units. To keep the relevant mid-game, these adventurers can receive permanent upgrades through accomplishments from easy things such as embarking out onto the open sea or difficult things like capturing an enemy city. These accomplishments are flavored with randomly chosen shorts to laud your brave adventurers.
There is more to the trait than what I've just described, though I would say they aren't the main selling point of playing the pirates. At this point I've got only one more faction to go. No idea how long it will take considering the gap between these guys and my last mod. However, I hope everyone enjoys my latest release and looks forward to the last Alpha Centauri faction left on the list, The Cult of Planet.