... How important are they on a boat, with no gas/oline engines/appliances ? No generator, no heater. Do have propane / stove, and a Propane Fume Detector. I have a couple CO Detectors at home, plugged into the wall outlets. On the boat, are they battery operated or hardwired ... and how much current do they draw ? Where's the best location to put one, down low, up high, sleeping area(s) ? Are they all the same or is one model / make more recommended ? Thanks, cheers, John