M&G, your heart is the right place. The technology is here, available and intrinsically safe. New machines, when well maintained and responsibly used are, much quieter and less polluting, and when kept from swimmers, other watercraft, and each other, are safe. Speed limiting is quite simple but not accepted just as your car is not limited to the maximum speed limit. The root of the problem is and almost always has been human error. Whether it is neglect of maintainence, speeding, trespassing too close to shore, ignorance of instruction and training, or simple negligence it is always human factors that create these tragedies. I agree that restricting their range and licensing with mandatory safety courses for owners and users would help. When rules and regulation are introduced into a free market economy, independant policing is required though. That, I suggest, is a challenge.