Dead reckoning

Posted by R. Berg on July 31, 2005

In Reply to: Dead reckoning posted by Donald Cook on July 30, 2005

: : : : : : In the explanation for the origin of the phrase "dead ringer" it is noted that :

: : : : : : "Dead, in the sense of lifeless, is so commonly used that we tend to ignore its other meanings. The meaning that's relevant here is exact or precise. This is also the sense it is used in the term 'dead reckoning'."

: : : : : : I was given to understand that the orinal phrase was rather "ded reckoning" which was an abbreviated form of "deduced rekconing" a nautical term for estimating position by use of speed, elapsed time and direction to "deduce" a vessel's position. I cannot remember the source; am I totally wrong about this origin?

: : : : : I don't know. Interesting theory. The previous discussion of the phrase is at www.phrases.org.uk bulletin_board 3 messages 420.html

: : : : Forget the "deduced" explanation. The Oxford English Dictionary has a separate entry for "dead reckoning" as a phrase. That entry refers to the sense of "dead" defined as "unrelieved; unbroken; absolute; complete; utmost." (Return to ESC's post for the link to a previous discussion.)

: : : I do not think "[f]orget[ting] the 'deduced' explanation" will serve. As I believe, Oxford is landlocked but for the Thames, and perhaps ought to be a secondary source for information maritime such as the derivation of "dead reckoning".

: : : In the U.S. we have had an organization since the beginning of the 20th which publishes a handbook called, "Piloting and Seamanship". It referred to the "deduced" lineage many decades ago, in my own recollection.

: : : Militating to the correctness of this explanation is the fact that the Oxford cites "absolute; complete; utmost" as the sense of "dead reckoning", which is plainly in error: dead reckoning is in fact imprecise, and is a method of shorewise navigation without the use of tools such as a sextant. It uses assumptions, probabilities and guesses as a basis for arriving at a probable position for a vessel.

: : : That is not to say that it is unreliable. Dead reckoning was used by many, including myself, before the advent of more precise tools such as GPS.

: : : As the Oxford Dictionary ascribes a level of precision to dead reckoning which it has never owned, and there are other sources which ought to be expected to know what they are talking about, I submit it is in error in its description of the lineage of "dead reckoning".

: : This 'deduced reckoning' idea is one of those folk etymology explanations that won't lie down. As usual with these all that's needed is an element of plausibility and the aptitude to put two and two together to make five. The plausibility is supplied here by the fact that 'dead reckoning' uses deduction.

: : Dead doesn't mean deduced so, if the phrase originated as 'deduced reckoning' and then migrated to 'dead reckoning', it would have been as a misspelled version of 'ded reckoning'.

: : I can't find any reference in print to either 'deduced reckoning' or 'ded reckoning' until WWII, whereas the OED has many citations of 'dead reckoning' from as early as 1613.

: : So, should we believe a 20th US handbook or the OED as the best source of information about a phrase that originated in the early 17th century? (It's a pity Oxford isn't on the coast - think of the reputation they would have by now).

: : Anyone who is familiar with researching the origins of phrases knows very well that, once a phrase is part of the spoken language, it soon appears in print. Things happen faster in that regard these days but a 300 year wait is diff icult to believe. That goes double for any maritime language which is especially well-documented.

: : Dead here means absolute, as in dead centre, dead ahead or (how can I put this politely?) dead wrong. Unless you are willing to believe those mean 'deduced centre', 'deduced ahead' etc.

: If, a s you say, there are references to "dead reckoning" from early C17, then I probably need to defer to that. I wouldn't mind if you had posted a few examples from OED, though, even though I believe your statement.

: As for "ded" being transformed to "dead", that argument has no substance. In C17 and later spelling was slippery, at best, and "sounding out" ded could give one "dead", a conventional spelling of the sound. Which process, BTW, persists to this time of more standardized English spelling.

From the OED:
Dead reckoning. _Naut._ [DEAD a. IV.] The estimation of a ship's position from the distance run by the log and the courses steered by the compass, with corrections for current, leeway, etc., but without astronomical observations. Hence _dead_ LATITUDE (q.v.), that computed by dead reckoning.
1613 M. RIDLEY _Magn. Bodies_ 147 Keeping a true, not a dead reckoning of his course. 1760 PEMBERTON in _Phil. Trans._ LI. 911 The latitude exhibited by the dead reckoning of the ship. 1840 R. H. DANA _Bef. Mast_ xii. 124 We had drifted too much to allow of our dead reckoning being anywhere near the mark. ...