The GEMINI by Subeo is a submersible two-man craft with an operating depth of 50M and it is powered by a lead acid battery, 68v 130 amp hour capacity. It has a maximum speed of approximately 4 knots. The main pressure vessel is of carbon steel, hot zinc sprayed and finished with polyurethane paint system, the rest of the structural components are of 316 stainless steel. The fairings stability fins and surface buoyancy tanks are manufactured from glass reinforced plastic, the weight of the craft is approximately 3 tonnes in air.
The GEMINI has a depth range of 50m, even at this depth the pressure on the hatches is about 14 tonnes and the total pressure on the pressure vessel itself is about 125 tonnes. The operating depth is 50m as this is the maximum depth for breathing normal air which will enable users of the craft to flood the vehicle in the event of entanglement and escape the vehicle using normal breathing apparatus. The most interesting viewing is above 50m.
It has all the components of a large submersible namely:- surface buoyancy tanks, trim tanks, lead trim, lead acid batteries, life support systems, front and rear hydroplanes, a rudder and a very sophisticated control system consisting of a PLC (Programmable Logic Controller) and many electrically operated solenoid valves, pneumatic actuators, stepper motors, encoders and several electrical power systems. Its estimated forward speed is 4 – 6 knots and when the surface buoyancy tanks are fully blown will have freeboard of 300 – 400mm. The design and control of the submersible combines just about every engineering discipline. i.e. structural, electrical, mechanical, life support, physics, hydrodynamics and naval architecture.
Life support systems consist of oxygen flask and metering valve sufficient to keep 2 persons in the craft for 30 hours. C02 is removed by a C02 scrubber Near the surface the craft may be ventilated by an air inductor which sucks air into the craft when the small snorkel is above the water surface. Comfort, cooling, heating and dehumidifier is also incorporated into the craft. The air bottles and oxygen can be replenished at diving air stations.
Subeo have now improved on the design of the gemini to create the Aquarius. The Aquarius is a 3-person craft that will include the very latest technology in relation to its main propulsion systems. The heart of any submersible is its energy source, traditionally small submersibles and military submarines have
used lead acid batteries. These batteries give off explosive gas when charging which in the sealed space of a submersible can result in potential explosion if the gas is not monitored and vented. Aquarius will use the sealed nickle sodium battery, which is totally sealed and maintenance free. Aquarius will be powered by an integrated thruster system. This new development in propellor power produces a very small unit without water seals or expensive and complicated drives and gearboxes.
Aquarius will use a monocoque hull construction with integral buoyancy tanks making a streamlined and maintenance free craft. This type of construction enables the craft to be manufactured in a relatively short time and reduces the weight of the craft.
Aquarius will use the latest technology to monitor and control the craft but still maintain all the manual safety systems designed and built into the concept vehicle. Aquarius’ life support systems and comfort cooling/heating are part of a fully integrated system maintaining the cabin at an ideal level of comfort and air quality. Its life support consumables will be sufficient for a normal mission time of 2 hours plus a further 72 hours required by the classing authorities.