Using unlinked GPS and ‘head-up’ radar to find an isolated buoy in poor visibility can be frustrating, especially when the radar screen is dotted with targets and you can’t tell which is the one your want. Here’s how to sort them out: enter the mark as a GPS waypoint and hit the ‘GoTo’ button. Note its bearing on the GPS ‘page’ and translate it into a bearing relative to your heading. Set the radar’s electronic bearing line (EBL) to this, and the variable range marker ring (VRM) to the distance – also given by the GPS. The buoy should be the blip on the intersection, or very close to it.