Hi Craig, ALWAYS USE CHOCKS ....................!!!!!!! I became a firm believer in using chocks when I saw a pickup and trailer in the salt water in Clearwater Florida. He didn't use chocks. Ramp was wet. He was a cowboy. Backed the trailer into the water - con brio - stood on the brakes, and .......................with truck wheels firmly locked, trailer and truck continued sliding gently into the water, and finally came to rest with water over the hood of the truck. Oooops! I also recall seeing a picture of a Rolls-Royce (with trailer) in a similar predicament - water over the hood. Chocks behind the wheels limit your rearwards movement. They are an indispensable mechanical safety device. Even if parking brake is weak, the chocks will keep you firmly in place. I made mine out of 6" x 6" about 18" long by cutting off (at 45 degree angle) enough from each side so that a 1/2" to 3/4" flat ridge was still left between the slanting surfaces. They are painted red, for visibility, and a piece of rope is glued into a hole bored into the end of the chock. They are in constant use, and the Admirable is "Imperial Keeper and Positioner of Chocks". I also needed chocks for the car and the trailer before I got a trailer tongue extension for the M15. Back in my learning days with the MICRO, we would back down the ramp and stop. Then the Admirable would put chocks behind the trailer wheels (at the water's edge). I would disconnect the trailer from the car, pull forward 6 to 8 feet and stop. Put chocks under rear wheels of car. Then I would use an old piece of anchor rode and tie it to the trailer and the car. Next pull forward slightly to put tension in the anchor rode and release the trailer chocks. Reposition the car's chocks about 15 feet down the ramp (firm stop no matter what happened) Now, with Admirable pushing or pulling trailer tongue to guide boat into the water, I would back down to preset chock stop. With boat floating in the water, the operation was reversed. I drove up the ramp with trailer on end of anchor rode: Admirable got the car chocks out of the way, and I parked the car and trailer, removing the anchor rode and hooking up trailer to car hitch. Now we were ready to head home with car and trailer (a B&B) that evening, after sailing to the marina. With chocks it's a "no sweat" operation, and there is no danger of your car getting an urge to go swimming! Connie