Just messed around in the driveway today. With the boat on the trailer, I deployed the Powerdrive motor with the I-Pilot. Turned on the spot lock feature, and within moments, without moving the trailer, the steering function moved the motor about 45 degrees. The propeller did not start. Moved the truck about 18 feet forward before the motor turned 180 degrees and the propeller started running. Then moved the truck straight back about 14 feet and the propeller stopped and the steering turned back towards the original position. So with just a straight path and reversing direction, there was about an 18 foot movement of the boat from moving off the original spot and then back to it. It's my opinion that with the built in error function with the Govt GPS signal, it's probably about as good as you can expect. I don't believe it is possible to have the spot lock feature keep you positioned over a brushpile, verticle jigging and not get hung. It's great for the Canepole pee hold function and great for casting to a brushpile, but you are going to be able to suspend a bait in a brushpile and not expect to get hung when the boat starts drifting off. Gene and I welcome anybody else to do the simple experiment of deploying your motor and setting the spot lock, then moving you truck about, measuring what distance is required for the steering or prop function to start.