On a more serious note, there are a couple of real world issues. First, any such device would only work when the boat is experiencing some degree of "rolling" motion. It's unlikely you would get much on that perfect broad reach in calm seas. Like wind
, you can only collect it when it's there to collect.
Next, I think you would have to choose what kind of motion you want to harvest. My whole professional life was coming up with this kind of device and, although I haven't really given it a lot of thought, I think it would be a very complicated device that could function with both pitch
Finally, as far as an actual device, I can think of several ways to do this job. As always, the devil is in the details, but here are a some ideas for what it's worth.
First, a generator of any kind uses a coil passing through a magnetic field. That said, several device configurations come to mind. You could make a pendulum device that has a permanent magnet on the pendulum passing through a fixed coil. The pendulum would swing with the motion of the boat, either pitch
or roll, generating a pulse of electricity as it passes through the coil. Kind of like your inclinometer.
Another possibility would be a device like a gas spring similar to those used to hold car hoods open. Picture a cylinder containing a piston with one end open and the other sealed. Just a piston, no piston rod. The piston would be a permanent magnet and a coil would be wrapped around the cylinder. The "open" end would be connected to the sea below the boat. As the boat moves up and down, water pressure on the piston would move up into the cylinder, passing through the coil and generating an electrical
pulse and compressing the air in the closed end of the cylinder. When the wave passes and the water pressure decreases, the air pressure would push the piston back, generating another pulse and resetting the device for the next cycle.
Any such device using the motion of the boat would produce power intermittently, so you would have to charge a battery
to make usable power. That means that you would have to reach charging
voltage with the device and put small bursts of energy into the battery
. Since it would be at work all the time, you might be able to accumulate enough power in the battery to run whatever device it is you want to run. You might be able, for example, to charge a capacitor and discharge it into the battery when the charge reached an adequate level.
It would be a simple matter to make a proof of concept
model but, as I said earlier, the devil is in the details. How big would the coil have to be to generate a reasonable amount of power? For the cylinder device, you would have to move a lot of water quickly, so a big hole in the bottom might be required. Who knows, the infernal machine might be as big as a house. The world is full of good ideas. The really hard part is turning concept
into workable reality.