Sea multicopter
A large nuclear-powered ship, such as a repurposed aircraft carrier or a large cargo ship, is outfitted with a plurality of large downward-directed subsurface mixer propellers secured on its sides and/or ends. The propellers are positioned below the bottom of the ship and have blade lengths in the range of 10-60 m. They are coupled to the ship's steam turbines by drive shafts and gearing compatible with the required propeller power and rotational rates, typically 25-150 MW per mixer propeller and with blade tip speeds typically around 40 m/s. They produce a large-diameter low-velocity downward plume of surface sea waters below the ship that induces upwelling of cold nutrient-rich deep waters in areas where the cyclone genesis index is high. The downward mass-flow magnitude (typically 3-30 times the flow rate over Niagara Falls, but at only a few m/s) is on the scale needed for a small number of such ships to essentially end cyclone genesis in the Atlantic. At the same time, the induced upwelling of nutrient-rich deep waters is expected to lead to the newly mixed areas becoming highly productive fishing areas.
1 . A nuclear-powered sea-mixer ship for inducing mixing of ocean surface waters with deep waters, said ship comprising:
a plurality of steam turbines,
a plurality of downward-directed mixer propellers mounted on multiple sides to the ship,
a plurality of drive trains, each drive train of the plurality of drive trains comprising a high speed drive shaft, speed reduction gears, and a high torque vertical drive shaft for coupling power from a steam turbine of the plurality of steam turbines to a mixer propeller of the plurality of mixer propellers,
said mixer propellers are configured to be driven by the plurality of high-torque vertical shafts such that a net torque in the vertical drive shafts is less than a largest torque applied to any single mixer propeller.
2 . The ship of claim 1 in which at least two of said mixer propellers are further characterized as having diameters greater than 20 m.
3 . The ship of claim 1 in which said mixer propellers are further characterized as having ratio of mean pitch to diameter less than 0.5.
4 . The ship of claim 1 further characterized as having multiple rearward directed propulsion propellers and means for driving said propulsion propellers at rotational rates that are independent of the rotational rates of said mixer propellers.
5 . The ship of claim 1 in which said turbines are further characterized as having combined shaft power greater than 100 MW.
6 . The ship of claim 1 further characterized as having a landing deck sufficient to accommodate small winged aircraft.
7 . The ship of claim 1 in which said plurality of mixer propellers is further characterized as being an even number.
8 . The ship of claim 1 in which said drive train is further characterized as including a clutch, said ship is further characterized as having a control system capable of separately adjusting the amount of steam applied to each said turbine in response to control signals, said control system further characterized as being capable of quickly disengaging the clutch in said drive train in response to control signals.
9 . The ship of claim 1 wherein the plurality of steam turbines comprises four steam turbines, each steam turbine is coupled to the mixer propeller through the drive chain that further includes a clutch.
10 . The ship of claim 1 in which said high-torque vertical drive shaft is further characterized as being supported by a plurality of bearings between said mixer propeller and said speed reduction gears.
11 . The ship of claim 9 further characterized as being a re-purposed Nimitz-class aircraft carrier and having one clockwise driven propeller on each side and one counterclockwise driven propeller on each side.
12 . A method of cooling surface sea waters by utilizing a nuclear-powered sea-mixer ship for inducing upwelling of deep waters by driving a large-diameter low-velocity plume of surface sea waters downward, said method further characterized as utilizing an even number of subsurface downward-directed mixer propellers attached on multiple sides to the ship and driven by drive shafts and gearing coupling the ship's power to the mixer propellers.