Aquatic Terrain Armored Transport
The Aquatic Terrain Armored Transport, also called the AT-AT swimmer, served as a combat vehicle within the Galactic Empire. Its design mirrored the function of the terrestrial AT-AT walker, but for underwater environments. These vehicles were operated by specifically trained personnel known as Imperial Army pilots.
Characteristics
The AT-AT swimmer's production was a collaborative effort between Kuat Drive Yards and Hydrospeare Corporation. It originated from substantial modifications made by the Imperial Army garrison stationed on Kabaira to the standard AT-AT model.
The command center was connected to a spacious area accommodating passengers. Functioning in deep-sea operations alongside TIE fighter boats and aquatic assault stormtroopers, it was commonly stationed in Imperial aquatic military installations. The Y-85 Titan dropship was also capable of deploying the AT-AT swimmer. It had the capacity to transport 40 soldiers and 600 kilograms of cargo.
Its shell-like plating was engineered to endure and shield the vehicle against the immense pressures of deep water, the corrosive effects of salt water, and blaster weaponry. The head unit could rotate to provide firing solutions in any direction.
The AT-AT swimmer was armed with a pair of enhanced heavy laser cannons, similar to its land-based counterpart. To house the four supplemental repulsorlift engines necessary for buoyancy, its main body was wider than the standard AT-AT. These engines generated a powerful field that could deflect objects from the craft's underside, although strong swimmers could penetrate this field where it was weakest.
By the year 137 ABY, the design had undergone significant alterations. The version employed by Darth Krayt's Galactic Empire was capable of underwater operation and equipped with shields. It featured at least six laser cannons, including a rear-facing double laser cannon for defense against attacks from behind, and a launch bay for at least five Shark underwater fighters. While maintaining a similar appearance to the original, the updated design was more streamlined. The command bridge was also redesigned to resemble the standard AT-AT's command bridge. Furthermore, these vehicles were known to have transported Sith Lords on various missions.
History
Galactic Civil War
The AT-AT Swimmer, resulting from extensive modifications to the mech by the Imperial Army garrison on Kabaira, laid the foundation for the Aquatic Terrain Armored Transport. Eventually, it was mass-produced, and some units were deployed on Kaal. Their presence posed such a challenge to the Rebel forces on the planet that General Carlist Rieekan, while reviewing the Imperial Military's field manual, Imperial Handbook: A Commander's Guide, noted the necessity of importing attack submarines from Mon Calamari.
Sith-Imperial genocide
More than a century later, during the Genocide of Mon Calamari on Dac in 137 ABY, at least one modernized AT-AT Swimmer was deployed. It served to transport Darth Azard and Sith scientist Vul Isen to the Soheras Trench. There, Isen had created a Sea Leviathan, which the two used the Force to awaken and command to massacre the Mon Calamari prisoners held at Imperial Extermination Camp 28, and subsequently hunt down and eliminate every Mon Calamari it could find.