Tension to vibration electric generator

Status: Not yet posted to Halfbakery.com
Idea:
The goal is to get the power from a large sail on land, that moves slightly but with much power (torque) then typically releases the power (slacks) and then catches the wind again.

The way I do it is by investing a bit of energy in getting a horizontal string with a weight attached to its middle, to turn vertically. When pulled tight a strong vibration and rapid turning of the weight results. The vibration is the addition of power from the original turning, plus the extra power from the pull.

(To explain this in other words: Hold a rope that has a bead in the middle of it, loosely between your hands and start moving one hand back and forth till the bead is rotating in a large circle, first coming up, then going back down the other side.
Now pull it tight, and the winding turns into a strong vibration which turns the middle very quickly).

Generating power: There are two types of this motor:
a. Power from the vibrations can easily be retrieved by a magnet connected to the wire and a coil. This contraption would be near the tips of the rope. (Google for Windbelt)
b. Another possibility is to get the rotational energy transferred into the middle weight, if the weight is a "bead" magnet free to rotate inside a coil moving with it.

Steps to make: (for 'a' type motor)
1. String: Hold string loosely at two ends.

2 'Weight'. Put a bead through the middle of the string.

3. Generators (Magnets and Coils): Tie two magnets about 1/6th of the way from each end, each magnet in the middle of a large coil. (You can start with one "generator" on only one end of the rope for testing).

4. Structure: You need two poles.
"Head pole": On one you tie the end of the rope. It must be able to sustain the full pull of the sail, so you may need an extra rope tying this pole to the ground (or use a tree).
"Secondary pole": This pole holds the string in its lax position but allows the string to be pulled tight by the sail.

5. Pulley to sail: Connect the most tensive part of the sail to the rope with an extension rope and pulleys. The rope should be free to allow the weight in the middle to be a bit low when the rope is lax, but fully tense, when the sail is tugging.

6. Initiating Propulsion: Add a windshield wiper to the bottom of the motor to move the rope back and forth, so as to give the motor its initial propulsion. Or just add another magnet and coil (electromagnet) somewhere on the rope so its is "pulsed" strong enough for rotation.

7. Controller: Add digital control (or try it manually) so that the rope gets its "starting energy" only when the big power is on its way. (At typical 6 m/sec winds you have quite the digital time to check this and do something about it), and is removed once the big power is coming in.

Note: The whole contraption could be held vertically, but then you would need to hold the weight in the middle, and somehow to cause circular movement and not a pendulum. This could easily be achieved by two controlled electromagnets close to the end of the string.

For a 'b' type motor:
Add four strings connected to the main string and stabilizing the generator-coil in place when the string is tightened, but allowing the bead-magnet (also serving as weight) to turn freely. Two of these stabilizer strings would be the current wires.
Another way to do this, is to connect a magnetic bearing to the rope without allowing it to turn, and connect a weight on one side of the bearing. The outer part would then be the rotor, while the inner part would be the stator, and the string itself could be the two ends leading the generated power.