I was thinking about auto-pilots and their inputs. My gut tells me they must have an actual heading input: sat-compass, or gyro, or magnetic (electronic) xxx.x input. Some situations you also get a derived COG, course over ground, and that also translates to a xxx.x number. If you’re bopping around near a dock, that number will fluctuate wildly, but you’d never be using autopilot tied to a dock. The more I thought about it, using COG for auto-pilot should work. Does that make sense? Bad idea? Why?
Oooo yup. You’re exactly right. With any swell, the COG would shift pretty quick. Of course, the actual HDG would also shift… but it would act very differently. My gut tells me this is a horrible idea - but it the idea really got me thinking.
Ended up fixing the sat-compass, and using standard HDG for the auto-pilot. Thanks all! Exercise in thought I suppose