Since we're on the subject, I'm curious.
How exactly is the speed verified at a UIM kilo? Is it calculated distance/time, or do they use some kind of laser and/or radar device at the end? If it's the former, how do you precisely measure exactly 1km on the water? Laser range-finder? Surely not GPS, I hope. What's used to mark the start and stop? Buoys that drift and wobble? Land-based positions? And how does one ensure that a timing devices triggers exactly when a boat enters the kilo and exits the kilo? And who certifies/calibrates the devices in question?