I believe U-Haul has demo videos on exactly this

It sucks to learn a lesson this way when they could have learned it by reading any of the paperwork that came with each component, or watching a video about it, or not ignoring all the various people who have already likely tried to explain it in person.

At worst, the slowest of those methods of learning the lesson would have been an hour or less of their time. This way is gonna cost hundreds or thousands of hours. And worse, could have cost forever, or someone else's forever, or multiple.

Motorcycle wobble can be resolved in two ways:

Slowing down: this makes the wobbles frequency slower but bigger (til it disappears)

Speeding up 😱: wobble frequency gets faster so actually more stable. Gotta have the HP to do so though.

Here it feels like it's just uneven loading or just not made for those speeds.

It’s because they suddenly switched from going downhill to going uphill, and didn’t correct their driving to account for that. Going downhill, they were likely accelerating to get past the traffic. So the boat was actually being pulled downhill. Then when the slope began to change, they stopped accelerating because they were past the traffic.

This means the boat’s inertia was suddenly pushing the car, rather than being pulled by it. If they had continued accelerating up the hill, (and thus, kept pulling the boat) they would have been fine. But since they were starting to slow down, (and the boat was pushing them from behind) they essentially got PIT maneuvered as soon as the back end wasn’t perfectly straight.

Either way, the correct solution would have been to accelerate. But inexperienced trailer drivers often panic and brake as soon as a wobble starts, which only makes it worse. Imagine the trailer being held by a rope instead of a ball hitch. You’d want to keep tension on that rope constantly, so it doesn’t go slack. Because if you put slack in that rope, the trailer will try to veer off in one direction or the other, and you’ll be along for the ride. That’s essentially what happened here. They went from pulling the trailer to being pushed by the trailer.

They were going downhill towards that bridge. Once they reached the lowest point (the bridge), they would naturally start slowing down and the boat would be pushing into the car, making the connection point want to go in a perpendicular direction from where the vehicles are going + at the same time the wobble gets worse because of the deceleration.

If they had been descending slower in a controlled manner, then they would have had enough power margin at the bottom to accelerate out of the pickle, but instead it seems like they sped downhill at max power, so they had no margin left. The vehicle was probably more than adequate for the job, but speeding down hill is usually not part of the job description of towing.

You think? this cretin is passing not one but TWO cars at high speed, uphill, towing a boat! might is below understatement.