[R-390] Magnetic compass and true north

[Roger Gibboni]

yes sir but pilots navigate to magnetic north always. boats---for some
reason---are different. they use true north. Don't know why. Maybe avoids a
conversion from celestial sightings when they used that--R

Roger Gibboni
Chief Operating Officer
Dulye & Co
Spectator Free Workplace
(Office) 845-987-7744
(cell) 845-325-8760


On Tue, Sep 9, 2014 at 9:33 AM, Sheldon Daitch <SDAITCH at bbg.gov> wrote:

> Roger,
>
> The wet compass points magnetic north/south, not true north.  But you'd
> know true north from the magnetic declination charted information.
>
> 73
> Sheldon
>
>
>
> -----Original Message-----
> From: R-390 [mailto:r-390-bounces at mailman.qth.net] On Behalf Of Roger
> Gibboni
> Sent: Tuesday, September 09, 2014 4:01 PM
> To: Blair Batty
> Cc: R-390 at mailman.qth.net
> Subject: Re: [R-390] OT: Submarine navigation
>
> Directional gyro that was reset with star sightings when they could
> surface.  The longer between star or sun shots the more th DG drifted.
> Same as in an airplane.  Enen today the only true north pointing instrument
> in an airplane is the wet compass.
>
> Roger Gibboni
> 845-987-7744
>
> > On Sep 9, 2014, at 8:40, Blair Batty <blairbatty at gmail.com> wrote:
> >
> > Sorry for the off topic, but I know there are lots of ex-military
> > types here; I don't know where else to ask.
> >
> > How did a submarine navigate during WW2? Did a compass work underwater
> > inside an iron tube? Did they just look thru the periscope to see
> > where they were going? Dead reckoning? Or were they mostly a surface
> vessel.
> >
> > I suppose today they have all sorts of magic, electronic gps devices,
> > so they can travel for months without every surfacing. But what was
> > available, say in the 60's-70's?
> >
> > Sincerely
> > /b
> >
> > Questions inspired by a cold war submarine movie last night...
> > ______________________________________________________________
> > R-390 mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/r-390
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:R-390 at mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net Please help support this email
> > list: http://www.qsl.net/donate.html
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>