GPS Anchor Alarms
The accuracy figures that most people use (including Garmin) are:
1. GPS with SA: 100 meters
2. GPS w/o SA: 15 meters
3. Differential GPS: 3-5 meters
4. WAAS: 2-3 meters
While 12 a meter error (a boatlength) could certainly make a difference navigating a narrow channel in very poor visibility, it is unlikely that the graphic display on a WAAS GPS would even render that level of detail.
So, for me, it''s not really an accuracy issue. I''ll buy a new GPS unit for the chartplotter and for the built-in navaid database.