Ron,
Quoting from AMERICAN PRACTICAL NAVIGATOR-BOWDITCH,1977, Defence Mapping
Agency Hydrographic Office, page 56: "The expression "dead reckoning"
probably originated from use the Dutchman's log, a buoyant object thrown
overboard, to determine the speed of the vessel relative to the object,
which was assumed to be "dead" in the water. Apparently the expression
"deduced reckoning" was used when allowance was made for current and wind.
It was often shortented to "ded reckoning" and the smilarity of this
expression to "dead reckoning" was undoubtedley the source of the confusion
that is still associated with these expressions."
I hope this helps, but I'm not sure it will.
Bill
