O'Neill-class ship

"...it is the most advanced technological Asgard creation yet."

- Thor

The O'Neill-class ship was the most advanced warship in the Asgard fleet, and the first series of Asgard ships designed solely to fight the Replicators.

Overview
"The vessels you face are far superior to the one you attacked. Challenge us at your own peril."

- Freyr

Named in honor of Jack O'Neill of the Tau'ri, O'Neill-class ships dwarfed the Prometheus and Ha'tak vessels in both size and firepower. These vessels carried the most advanced weapons created by the Asgard (excluding their plasma beam weapons). The O'Neill-class replaced the Bilskirnir-class as the Asgard vessel of choice when engaging hostile forces. These vessels were powered by an unknown number of neutrino-ion generators, and possessed fifteen Asgard transporters. The Asgard were constructing an entire fleet of these ships to replace their Bilskirnir-class vessels, and already had several O'Neill-class ships constructed by the time of the Ori crusade.

Design
"Wow! That's an impressive looking ship."

- Samantha Carter

The O'Neill-class shared the same aesthetics as other Asgard spaceships, with smooth, curving lines and parallel sets of projections. Overall these ships were similar in appearance to the Bilskirnir-class, except with a curved, bulging "head" design for the bow instead of the "hammer" design featured on the Bilskirnir-class. The rear of these ships house two engines with visibly glowing thrusters, also similar to the Bilskirnir-class.

Maneuverability
O'Neill-class ships were very maneuverable, as witnessed during the Battle of P3Y-229. During the battle, the participating O'Neill-class vessel was seen making sharp turns at high speeds and engaging in dog fighting-style tactics, despite its massive size, which, in part, allowed it to last far longer than the other vessels of the allied fleet.

Technology
O'Neill-class vessels, incorporating the most advanced technologies the Asgard possess, were among the most powerful ships in the known universe. Only Ori warships, designed and built with ascended knowledge, were proven to be a match for them. Even then, the only time an Ori warship bested an O'Neill-class vessel, it had the advantage of numerical superiority (4 to 1), and it is unknown if the O'Neill-class ship was actually destroyed.

Hyperdrive
The hyperdrives on the O'Neill-class were far superior to those installed on the outdated Bilskirnir-class, and quite possibly the fastest hyperdrives ever constructed. These hyperdrives proved capable of traveling between the Ida and Milky Way galaxies in only a few hours, and towed the Prometheus back into Earth's orbit across 1200 light-years in mere seconds. The Prometheus was later towed to the Ida galaxy in less than a day (much slower than if the Asgard ship was traveling alone but far faster than what any other known vessel apart from a fully powered city-ship was capable of).

Shielding
The shields of the O'Neill-class were some of the most powerful ever designed, capable of withstanding multiple hits from both the central beam weapon of an Ori warship and its secondary pulse weapons, both of which were capable of destroying Ha'taks in no more than a single or handful of hits, respectively.

Weapons
The O'Neill-class was armed with 4 powerful energy weapons; two of which were visible on both of the ships "wings", with two more at the bow of the ship capable of retracting into the hull. Designed to penetrate the shielding systems of both Replicator ships and Anubis' upgraded Goa'uld shields, the ion bolts fired by these weapons were capable of refracting to bypass a shield and strike a target multiple times. These cannons were the only known energy weapons capable of destroying Replicator blocks (which have traditionally been impervious to energy weapons) through sheer kinetic force, and were also shown to be powerful enough to counteract the upgraded shields on Anubis' Ha'tak.

Known ships

 * Freyr's O'Neill
 * Kvasir's O'Neill
 * O'Neill
 * Valhalla
 * Thor's O'Neill