I had a great idea today to save time. So, I thought! I rented a dumping trailer today for a removal. When it came time to fell the tree I had the idea of felling the tree into the trailer while the trailer was in the up position. I made a 6:1 mechanical advantage pulley system with a lock on it. I made my notch shallow so that when the tree was pulled over it would gently lay into the trailer bed.
Well, I pulled it about one foot from the trailer bed and I was at the end of system. (The pulleys stopping eachother from moving any further) So, I had to release the tree with the saw. Where I made my notch the diameter was a little over 3'. The height of the rest of the tree was only about 12'.
What happened next never crossed my mind as to what could have happened. My truck was slightly down hill, maybe a 1% grade. When the tree hit the trailer, it poped my truck out of gear (e-brake broken), rolled the truck and trailer into a car! Good news. The customer collects cars for scrap. I counted nearly 12 Datsun 280Z's in his yard. The one I rolled into was not to worry about. The customer didn't care.
So, I had a great plan to cut a corner and didn't see that one comming. (See attachment for graphic example)