Steve wrote:
Were is vertical clearance measured from (what datum)?

Should be Mean High Water.

I can't seem to find this information in any of my reference books.

Could have sworn it was in Chapman's, but my copy is on my bedside table
and my wife is still asleep.

Chart 1 (http://www.carolinaglobalmaps.com/pr...cal/chart1.htm)
says: the shoreline is "usually the mean high water line" (p 4) and
heights of landmarks and structures are "referred to the shoreline plane
of reference" (p8).

regards,

dave
M/V Auspicious
"a sailor fallen from grace"