For anyone who became interested in this discussion.... I finally got in touch with a knowledgeable person at Garmin. It took several calls and a lot of time on hold. Basically he told me that the electronic compass feature on the Garmin 76S and a couple of other Garmin units are pretty much for walkers but not for sail or aviation use. In other words, one can use the unit to obtain heading over the ground when moving (just like any other GPS) but the compass is not great for obtaining direction steered. In order for the electronic (fluxgate) compass on the Garmin 76S to work well the unit has to be held flat and not be around any metal or magnetic fields, both of which are pretty common in a cockpit. He suggested disarming the electronic compass (which I cannot figure out how to do) or at least changing the factory default setting so that the unit utilizes the GPS to obtain heading at low speeds and not the compass (easy to do and the instructions in the manual are straightforward).