USS Alexandria

The USS Alexandria was a Los Angeles-class submarine used by the United States Navy.

In an alternate timeline, the Alexandria was used to head a training operation in the Arctic, when they detected the unstable vortex of a Stargate from a satellite. They headed toward the location and found and picked up Daniel Jackson, who had frostbite and had his left leg amputated. The crew, along with Colonel Jack O'Neill, later picked up Cameron Mitchell and Samanthat Carter, after they discovered their timeline was altered.

Behind the scenes
The submarine used in the filming of Stargate: Continuum was in fact the Alexandria and the crew of the vessel was played by the actual Alexandria crew.