The Nautilus 4D Bathymetric Charting System from The Capn shows bottom contours in real-time and lets users build their own accurate three-dimensional charts as they drive their boats. The PC-based charting system uses real depth soundings from a connected depthsounder to collect data and place it on an electronic chart via a connected GPS unit. Nautilus 4D requires a computer equipped with a Pentium III or better processor, at least 512 MB RAM, at least 16 MB Video RAM, a serial port and an NMEA-output depthsounder. The system comes in Recreational, Sportsman and Commercial models and starts at $395. The Capn by Nautical Technologies, Bangor, ME; (800) 637-4020; www.thecapn.com.