Old age has caught up with me help. On my navionics map it says 'line of leads 238 D'
What does the D represent. ( t, mag, grid ?)
thanks.
in looking up the same same map in beacon to beacon it shows 238t . Perhaps an error or other language for true by navionics.
edit.
If I am correct D is for Deg. Ie degrees

I recon you've cracked the code