Just as an add on to the thread. I went on a sailing refresher course recently and was taken aback by the amount of time that people were taking finding position on a paper chart using lat longs from a gps. Particularly in view of the fact that the approx position was known. Time spent below was counter productive in a very busy shipping area I thought.
Coming from an aviation background, It occurred to me that whilst flying along at 130 kts I never had time to bugger around with lat longs and always used VOR/DME. What this system comprises of is a ground station (they are everywhere) that sends out 360 signals so you can always work out which spoke you are on from the compass rose on the map. DME is another signal that shows your distance from the station in miles. therefore you can now see where you are on the map very accurately.
Whilst in the cockpit on the sailing course I decided to make use of a virtual VOR on my marine chart. Of course they are there already. there are compass roses on all charts usually with the lat long shown. All you need to do is programme in chart compass rose as a waypoint on your handheld GPS, then with folded chart in hand, you can see where you are using a straight edge scaled with distance for your chart (if you use a scale distance ruler, you need to watch the scales of the charts of course)
At any time, the gps will give you distance and bearing to your compass rose and you can see where you are.
Is this too simple and should I climb back in my cockpit, or is this idea of any use to anyone . Aviation shops sell those stick on compass roses so you can position them over any suitable waypoint and use the straight edge on that.