Radar
Have used it on board a schooner cruising the New England coast. Does a great job supplementing the usual bearing line fixes for navigation, particularly at night. And, during limited visibility it offers some indication & assurance of "what's ahead" that GPS doesn't.Is it "right" for every boat -- probably not. Daysailors, or those who do limited daytime cruising restricted to fair weather, don't really need it, particularly with cheap handheld GPS these days.On the other hand, I believe EVERY boat in the water that ventures out of a harbor should be equipped with a radar reflector or transponder to make them "electronically" visible, particularly to search & rescue craft. There are new passive devices with all aspect angle lunenberg lens technologies that can be fixed at a mast top with minimal weight & windage. They could be very reasonably priced in an environment where they are installed as original equipment during mast production.