when they shut everything down and go to sleep 10 miles off shore. When I say shut everything down I mean turn off the outboard motor and the 12 watt rear chevy tail light bulb they have hanging from the stick nailed to the side. I missed one by about 20 feet and he turned on his light AFTER we passed him. Their wasn't so much as a dot on my Radar screen and I have a pretty good unit. It was in the middle of the night with no moon and choppy sea's. The seas were choppy but not to the point where I had the sea clutter turned up so he just gave off a zero target and we could have had some pretty extensive damage.