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    Re: recommendation for slide rule ?
    From: Greg Rudzinski
    Date: 2009 May 20, 09:38 -0700

         Thanks for the heads up on SLIDE RULE FOR THE MARINER. I just
    ordered a used copy. There are more available if anyone else is
    On May 20, 8:56�am, Hewitt Schlereth  wrote:
    > A useful book is Henry H. Shufeldt's "Slide Rule for the Mariner." He
    > goes quite thoroughly into use of a 10" K&E Log Log Duplex Trig rule
    > for cel nav. Checking with Amazon I found 2 copies of the book @
    > $15.49.
    > Hewitt
    > On 5/20/09, Brad Morris  wrote:
    > > �The slide rule was used everywhere, not just the moon landing. �Consider, 
    the electronic 4 function (+-*/) calculator was marketed the early 1970's. �I 
    still fondly recall my first calculator and marveled at the decimal digits 
    and the speed. �I wouldn't let anyone touch my precious instrument! �Any 
    engineering that was done before 1973 either used a mainframe computer or a 
    slide rule.
    > > �Mainframe computers were gigantic beasts. �Nothing like the desktops of 
    today at all. �Remote operations happened (at least for me) at 110 baud. 
    �Yawningly slow. �Even when you were local to the mainframe, things took 
    time. �You submitted a job and the answer, after a period of time, popped 
    out. �They were expensive to operate and maintain. �Associated with the 
    mainframe was a staff. Your job was scheduled in, there was no instantaneous 
    > > �The slide rule offers immediate results, with an answer that almost 
    always is "good enough". �The 10" rules were like a sword on your belt. �Very 
    awkward to wear. �I still have my pocket slide rule which did not suffer from 
    that, at the expense of even further resolution issues. �I kept the 10" at my 
    desk and the small one in my pocket. �The small one popped out in meetings.
    > > �The slide rule offers something that all the electronics in the world 
    does not. �It is the Order of Magnitude of the problem. �That is, you are 
    forced to estimate the answer in your head first and then stick the decimal 
    point where it belongs. �Essentially, you solve the problem before hand and 
    the only thing the slide rule does is to refine the decimal digits of 
    accuracy. �Since you only have 2 or 3 digits after the decimal point 
    (typically), you are forced to be conservative in your calculations. �That's 
    why many structures that were created with slide rules appear to be "solidly 
    constructed". They were compensating for the inability to resolve the 
    > > �I don't want to discourage you, yet I believe that the solution to the 
    spherical triangle on a 10" slide rule will not be of sufficient accuracy to 
    suit for navigation. �There simply isn't enough resolution. �Dutton 
    recommends that each navigator equip himself with one, but I believe that 
    this is to perform simple rate equations and trigonometric solutions, not for 
    the solution of a spherical triangle.
    > > �Mind, you will get a solution. �That solution will put you on the map. 
    �The only thing is just how accurate your answer is and how much do you need!
    > > �Best Regards
    > > �Brad
    > > �-----Original Message-----
    > > �From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Greg Rudzinski
    > > �Sent: Wednesday, May 20, 2009 12:50 AM
    > > �To: NavList
    > > �Subject: [NavList 8330] Re: recommendation for slide rule ?
    > > �Gary,
    > > � � �You have succeeded in getting me interested in slide rules. I
    > > �have never owned or used one but after some internet research I see
    > > �that they have been to the moon and back. Now I will have to get one!
    > > �So far I am leaning toward the purchase of a Pickett N3-ES which is of
    > > �aluminum construction. The slide rule could very well be the pinnacle
    > > �of low tech achievement. Right there with the mechanical chronometer.
    > > �Greg
    > > "Confidentiality and Privilege Notice
    > > �The information transmitted by this electronic mail (and any attachments) 
    is being sent by or on behalf of Tactronics; it is intended for the exclusive 
    use of the addressee named above and may constitute information that is 
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