Navigating in dense fog requires 100 percent of your attention to monitor the radar, keep an eye on the AIS and listen for noises such as approaching craft, the sound of a buoy or crashing waves on a jetty, not to mention pilot the boat. That’s why a VHF radio with an automatic foghorn feature can be a great — I say essential — safety feature when it’s socked in. State-of-the-art VHFs such as the Icom M605 (about $800) and Standard Horizon GX2200 Matrix AIS (about $320) offer automated foghorns when connected to an external hailer. You can select from foghorn modes for use while underway, stopped or on anchor. There’s also a listen-back feature that amplifies sounds such as other boats and aids to navigation.