[GreenKeys] Enigma machines

[surplus1]

Hello Everyone,  I was responsible for the ECM machines on the Battleship
North Carolina BB-55 during WW2..   The ones that we used were the Mark VII.
They had seven rotary wheels in them, operated electro-mechanically.  These
were changed every hour using predetermined order.  The first two and the
last two five letter groups in the message were used to start or stop the
decoding or incoding.  I saw one machine advertised years ago at a very
large price.  The people on the North Carolina have borrowed one to use as a
display so if you are around Wilmington, NC  you can probably see it.  I
can't tell you about the operation as long ago (1943) I made a solemn
promise never to discuss this with anyone.  I guess that after 66 years it
might be O.K.  Really enjoy reading the chats on GreenKeys.  John in WV

----- Original Message -----
From: "John Nagle" <nagle at animats.com>
To: <greenkeys at mailman.qth.net>
Sent: Monday, July 13, 2009 9:18 AM
Subject: Re: [GreenKeys] Enigma machines


> > Date: Mon, 13 Jul 2009 09:42:54 +0100
> > From: "Craig Sawyers" <c.sawyers at tech-enterprise.com>
> > Subject: Re: [GreenKeys] Fwd: GIZMAG & ENIGMA
> >> Does anyone know of selling prices of Enigma machines?
> >>
> >> I seem to remember one selling for twenty thousand or so a while back.
>
>     I've had the opportunity to operate an Enigma machine.
> Someone had a museum's machine on loan, and they brought it by
> Stanford about ten years ago.
>
>     The thing has the worst keyboard feel of anything ever built.
> You don't type on it, you push down keys with almost 1" of travel,
> and you're pushing against heavy resistance.
> The machine is powered by the key presses, which advance the rotors
> mechanically.  The only electrical parts are contacts, lamps, and
> battery.
>
>     The reason it only has three rotors is that if they added more, the
> key forces required would be hopelessly high.  There was a 4-rotor
> Enigma variant, but that never caught on.  Machines with more
> rotors were built, but they were motor-driven, not manual, and
> the WWII-vintage ones were bigger than a Teletype model 15.
>
>     They'd run into the limits of what one could build as a portable
> mechanical device.
>
> John Nagle
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