While the Loon Copter is not the first underwater drone, it is the first multi-rotor drone capable of filling its buoyancy chamber to sink underwater, tilt 90 degrees and move around beneath the water's surface.
The solution, the SeaStar XI, is a propeller driven craft powered by a 12v, 125W electric motor and lead acid battery arrangement contained within a watertight buoyancy chamber. It would cost [pounds sterling]249.99 to buy, moves at up to 3kph, weighs 8.7kg, and is able to run for 55 minutes off a single battery charge.
Turbine supports of the buoyant type are the only economic solution for large turbines in deep water and as they become increasingly available there will be the opportunity to use the buoyancy chamber for compressed-air energy storage.
The buoyancy chamber of a 6MW turbine in 80m water depth when pressurised to a relatively modest 10 atmospheres contains enough stored energy which, when released through an expander-driven generator, could provide 3MW of power over a one-hour peak demand period.
It is frustrating that more space is not given to more attractive energy storage systems, such as using the buoyancy chambers of floating wind turbines for the storage and recovery of energy as compressed air.
The vessels were called back to dock 48 hours after safety checks discovered some craft were defectiveA total of 38 of the boats had broken buoyancy chambers - meaning they would not have properly inflated in an emergency.
It primarily consists of a vessel with a circular cross-section that sits vertically in the water and is supported by buoyancy chambers (hard tanks) at the top, a flooded mid-section structure hanging from the hard tanks, and a stabilizing keel section at the bottom.