I'm interested in origin of the term "dead reckoning". I read somewhere that it came from "ded' reckoning" i.e. "deduced reckoning". Any thoughts?
Tony Moss. Tony and all, I doubt if "dead" reckoning has anything to do with "deduced" reckoning. There is a parallel nautical case where "dog" watches, the half watches used to change watch order in successive days, was supposed to be derived from "docked" watches. I recently wrote to the "Mariner's Mirror" as follows: That the word "dog" is a corruption of some other word, as "dock", or "dodge", seems to me unlikely. Is it not more probable that the word is one of a family of modifying prefixes used to signal that the substantive is not the real thing. Examples include dog-latin, french leave, dutch courage, horse-chestnut and cat-silver. Other examples are easily supplied and the usage is so common that this seems a sufficient explanation. Dog-watches are not real watches but only half watches. In the same way I think we should concentrate on possible meanings of "dead" and not look for corruption of other words. There are similar problems with "neap" and "spring" tides. -- Frank Evans
