Q: Is it dangerous to the driver?

A: Not in this configuration. It's a lot safer than any wind-turbine boat yet made. The blades are adjusted so that they never travel faster than the windspeed. (This is known as a 1:1 tipspeed ratio).

This is marked contrast to the other well-known design below which uses blades which travel over 100 miles an hour.

Secondly,  these blades are very light and are in fact made mostly of balsawood.

Thirdly, the blades don't pass near the driver anyway.

Q: How does it differ from this craft?

A: The boat above uses a much larger rotor (about 40ft) which is designed to extract the maximum power out of the wind, but with little consideration of the practicality of putting it on a boat. It cannot be allowed to rotate in harbour or near other boats because the diameter is much greater than the beam of the boat. Because of the thin blades it has to rotate very fast and therefore contact by anything with the rotors (human or boat) is very dangerous. This kind of rotor with low blade area does not work well in light airs. By contrast with "Jensa" (top of page)  which will move in very low windspeeds.

Although the "party trick" of this boat is that it can sail directly against the wind, the designer has not given any consideration to optimising this. The thick "mast" remains circular cross section, when a lot of drag could be saved by making it a teardrop streamlined shape. Also the large upper windscreen is another drag producing appendage that will tend to limit its speed directly to windward. You can only assume that the designer was not concerned about getting the best performance.

The design philosophy of "Jensa" (the boat at the top of the page) is one of safety and practicality. The rotor does not extend beyond the beam of the boat and it rotates much slower but has more blades. There is no loss of performance and it will work even in the lights airs, as should be apparent from the video on Youtube.

More information on Horizontal Axis rotary sailing