do most fishing boats so while I love my AIS I still rely on Radar. IMHO, on a small sailboat AIS is just another adjunct. It's just another thing that helps. If you stack enough things around yourself you're less likely to get hurt. It's like a depth sounder, or a chart plotter, or a RAM mic in the cockpit. You can get by with out them but why would you want to. If you can afford it, install it. It's just one more level of protection. As for if watch keepers on ships are watching, when ever I call a ship I never get an answer on the VHF. I get crickets. My wife on the other hand gets an answer every time. Make that every time!