This is a good time of year to be ruminating over boat improvements. My own experience, as well as anecdotal info from others, suggests that shipping traffic does not always maintain a radar watch. But do container and cargo ships have AIS receivers? What do people think about class B transponders for coastal and offshore a tool to reduce risk of bumping into a ship? I am also interested in the cost part of the equation....both in terms of money and power. My boat is set up for sailing with low power load: Monitor steering offshore, LED tricolor, NASA AIS receiver, no chart plotter, no radar, etc. The little NASA "Radar" unit is one of the best purchases I have made and draws only about 50 mA; 100 mA with the backlight turned on. How much power does a class B transponder require? I think Culebra and perhaps a few others have a transponder installed...any thoughts?