Having been invisible to 3 boats on wrong side of a channel who seemed more interested in bringing the charter fishermen home, it made me realise how vulnerable I was to boats not keeping a proper lookout so investigated these things on the chance that someone in the wheel house might spot me on their radar.
However, after reading this article, decided that without a bigger boat with 4m mast and £500 I would be just as invisible.
http://www.yachtingmonthly.com/fileB...ce_ym_june.pdf