Go get you some 5/8 braided dock line 25 foot long and attach a heavy duty clip/snap on each end. I have been using this trick for years. The extra length lets you pull the truck and trailer up without it coming up to the boat ramp.
This. I've been doing this since the 1970s, and have never had a problem. Quick, easy, and inexpensive. No need for gimmicky items, either. Dock line, 2 bowlines, and two carabiners do the trick. It's then very easy to unsnap the 'biner from your trailer, push the boat out, and pull it to the side so other people can use the ramp....kind of the ideal solution, IMHO.