Map coordinates - lat/long & BNG

Hi, I have a couple of questions about coordinates displayed when I save a man overboard (MOB) position:

based on the gps tracks my watch records on the map when I run or hike, my watch clearly knows where I am but the MOB coordinates displayed are not correct. Having checked on multiple mapping sites they are out by quite some way (definitely much more than typical gps error). Has anyone else noticed this? Can this be corrected?
this is more for uk based people. The BNG coordinates are displayed as 2 letters followed by 5 numbers. I’m used to seeing 6 or 8 number grid references. How do you interpret a 5 figure grid ref?

thanks!

0 tmk2 over 5 years ago

3854086 said:
the MOB coordinates displayed are not correct. Having checked on multiple mapping sites they are out by quite some way

Can you provide some examples? Are you sure the same coordinate system is used both on your watch and the mapping site?

0 3854086 over 5 years ago in reply to tmk2

Hi, it took me a while to getting around to this but I finally took a MOB location at a trig point so that I could determine the exact grid location and it turned out my watch was pretty accurate (wl within gps expectations). It turned out that I was reading the grid coordinates incorrectly!