Sokar's Ha'tak was a Ha'tak used by Sokar and the flagship for his massive fleet.
Design
This Ha'tak vessel looked like all other known Ha'taks. Since it served as the mothership of a powerful System Lord, it is possible that it is superior to standard Ha'tak vessels but this has never been proven.
History
After SG-1 and Martouf launched a rescue mission for Jacob Carter/Selmak, Apophis used the opportunity to stage an uprising on Netu. Sokar, learning of this, agreed to meet with Apophis and takes his Ha'tak into orbit over Netu. Sokar planed to use its weapons to cleanse Netu's denisens from the hellish moon before taking his fleet in a massive attack on the System Lords that would overwhelm them as his fleet would be ten times that of anything they posses.
Sokar took his Ha'tak into orbit and met with Apophis, who ringed aboard. Meanwhile, the Tok'ra Aldwin, took this opportunity to kill Sokar. Knowing that no weapon the Tok'ra posses could penetrate the Ha'tak's shields, Aldwin launched a bomb into Netu's core that would destabilize it and cause the moon to explode and obliterate the Ha'tak. The plan to destabilize the core worked, and Sokar's crew didn't detect it until it was almost too late. Sokar, having learned that Apophis was apparently lying to him (he wasn't, he believed he was telling the truth but planned to assassinate Sokar), was preparing to execute him when the news arrived and caused enough of a distraction for Apophis to escape.
When Teal'c flew SG-1's Tel'tak in between Netu and the ship to rescue SG-1 via the Transportation rings, the Ha'tak fired on it. Teal'c successfully completed the rescue and got away. Netu exploded, destroying Sokar's Ha'tak in orbit and killing Sokar. Unfortunately, Apophis got away by ringing to Delmak before the ship was destroyed. With Sokar dead, Apophis took control of his massive army and fleet. (SG1: "Jolinar's Memories", "The Devil You Know")