re the datums yes i agree on that , reminds me of a famous warship that hit a very large rock in the SOUTHERN HEMISPERE.did not check DATUM on chart! datums currently being used
wgs 84 osgb36 then ned and lots more ( more and more now printed WGS84)
i would steer clear of directories
and never plot a bouy as a way point , last year Sunseeker delivery hit a bouy
at night and yes it was lit , much better to set it to one side of a bouy so you get a visual fix as you pass , and if using 6 min rule great as a back up.