Originally Posted by wwilson
A + or - 2˚ compass sighting of an object 1nm away is pretty good on flat water and unobtainable on a pitching deck. That alone can produce 47 meters of error!
I guess the point that I would make is that if you have something that is 47 metres away, you should have no interest left in the chart - only in whatever is 47 metres away!
There is an old adage that I have always applied to navigation - "You are NEVER where you think you are". As far as my navigation goes, if there is something near me that represents a danger to me, nothing beats a look out the window.