The Aqua-Evac is an underwater vehicle used to transport passengers should the Ulysses be compromised. It is big enough to transport several vehicles, a hefty amount of supplies, and up to roughly one hundred people.
In Atlantis: The Lost Empire, at least four Aqua-Evacs were launched when attempting to escape the Ulysses, which was on the verge of exploding due to the damage it received from the Leviathan. One Aqua-Evac was unable to get far enough away from the submarine, thereby being destroyed by its accompanying explosions. The Leviathan destroyed a second Aqua-Evac by smashing it with its claw and caused the destruction of a third when its energy blast crippled the ship and caused it to crash in the narrow tunnel passage. The remaining Aqua-Evac, operated by Helga Sinclair and containing the core members of the Whitmore Expedition, made it to the catacomb caverns. It would be abandoned at the entrance for the remainder of the journey.