Tankers were used to shuttle liquids from earth to the motherships. Tankers are similar to Transports in 8-cabin configurations, but tanks replace the inner six compartments. Tankers are 38 meters long and 10 meters wide, and support a crew complement of only four: pilot, co-pilot, one technician, and a safety engineer. Tankers are similar in speed to transports: 0.9 Mach within an atmosphere and 10-20% speed of light in space. Power source, propulsion, and composition are similar to that of the other shuttlecraft. The navigation system is a simplified version, capable of automated control for pre-programmed journeys. Tankers also have reinforced landing gear and structural bracing, as well as pressurized storage cylinder tanks composed of a self-sealing, non-osmotic alloy. Tankers do not carry any armaments.
They have not appeared in the new series.
Tankers were vital for the Visitor's takeover of the Earth. To continue their intergalactic war, they needed more resources like food (humans) and water.