The YZ 3000 tanker was a model of transport vessel. The YZ 3000 was colloquially known as a "Whale" due to its massive size and shape.
These transports were used to haul water from Da Soocha to its moon of Napdu in 137 ABY for use in the Maya Armus spa. The Galactic Alliance Remnant used several of these to evacuate Mon Calamari refugees from the planet. Gar Stazi soon after called them back into service during the Evacuation of Dac, where they were used to save Whaladons and Moappa.