Weighing in at 3.5t and powered by 68v, 130amp/hour lead/acid batteries driving a 4kW electric motor, Gemini is claimed to be capable of speeds of up to 4 knots. At 2 knots endurance is around seven hours, while the life support system can keep two occupants in comfort for an entire day. They sit side by side with their heads projecting from a 1.8m diameter, 10mm thick carbon steel pressure hull into 25mm thick 600mm diameter acrylic domes which double up as access hatches.
With all four main ballast tanks blown Gemini has a freeboard of 300mm below the hatches. It can be fitted with ultrasound communication equipment, video and film cameras, or extra lights.
The controls have manual backup in case of power failure and the PLC can be programmed for special applications such as training.