Thanks Chuck, it seems that our docent that day was less than well informed
and that some of the projectiles did include explosive charges. Also, the
maximum projectile weight was ~1/2 ton, not 3/4 ton. Now I wonder what
other misinformation we were given. Oh well, at least we didn't pay for the
service. :-)
Cya,
Johnny
---------------------
Johnny Johnson
Cleveland, GA
On Mar 10, 2012 9:57 AM, "Chuck Norcutt" <chucknorcutt@xxxxxxxxxxxxxxxx>
wrote:
> For those of you so inclined here is the entire 136 page "user's manual"
> for the 12-inch Mortar Model 1890MI.
> <
> http://www.scribd.com/doc/17375868/TM-9456-12inch-Seacoast-Materiel-12inch-Mortar-M1890MI-Mounted-on-12inch-Mortar-Carriage-M1896MI-and-M1896MII
> >
> All of the info about the various forms of ammunition is found on pages
> 77-101 (according to the index) :-)
>
> Chuck Norcutt
>
>
> On 3/10/2012 8:52 AM, Johnny Johnson wrote:
> > Don't know the answer to your question Chuck but when I was there I was
> > impressed by the sheer size of the projectiles and the range. If I
> remember
> > correctly they were on the order of 3/4 ton each and had a range of seven
> > miles with a maximum altitude of ~three miles. They didn't contain
> > explosives, just depended on the weight of the projectile to do the
> damage.
> >
> > I do remember seeing the photograph that has you puzzled. My only
> reaction
> > was to think of how neat it was that they caught the projectile on film,
> > not the technicalities of how it was done.
> >
> > Cya,
> > Johnny
> >
> > ---------------------
> > Johnny Johnson
> > Cleveland, GA
> > On Mar 10, 2012 8:00 AM, "Chuck Norcutt"<chucknorcutt@xxxxxxxxxxxxxxxx>
> > wrote:
> >
> >> As a possible answer to my own question it occurred to me that the
> >> projectiles (at only about 1/300 second after firing) are probably being
> >> illuminated by the bright flash of the guns. So the film was probably
> >> exposed by the flash of the guns and not the ambient light. Sort of a
> >> built-in strobe and not requiring a fast shutter or fast film. Sound
> >> reasonable?
> >>
> >> Chuck Norcutt
> >>
> >>
> >> On 3/10/2012 7:34 AM, Chuck Norcutt wrote:
> >>> Yesterday we went with some friends to Fort DeSoto Park for a picnic
> and
> >>> a bit of beach lounging.<http://en.wikipedia.org/wiki/Fort_Desoto>
> >>>
> >>> While a very large public park today, Fort DeSoto was originally
> >>> constructed between 1898-1906 as a coastal defense battery to protect
> >>> Tampa Bay. If you scroll to the bottom of the page linked above you'll
> >>> see some of the artillery and mortars originally installed here and at
> >>> Fort Dade a short distance away. With 12" bores the mortars are rather
> >>> impressive beasts. They were first fired in 1903 and were deactivated
> >>> not later than 1917.
> >>>
> >>> In a long corridor of historic photographs of the guns and emplacements
> >>> there is one very faded shot of two mortars being fired at the same
> >>> time. Much to my amazement the projectiles of both guns are clearly
> >>> visible perhaps some 30 feet above the muzzles. According to the
> >>> details I've been able to find about these guns the muzzle velocity
> >>> ranges from about 1,000 to 1,500 feet/second depending on the weight of
> >>> the projectiles whose length ranges from about 3-4 feet.
> >>>
> >>> Now the shutter speed mystery. How was this photo taken? At 1/500
> >>> second the projectiles moving at 1,000 feet/second move 2 feet or 4
> feet
> >>> at 1/250 second. The angle of view from the camera's position probably
> >>> creates some foreshortening of the projectiles but it *appears* to me
> >>> that the shutter speed would have been not longer than 1/250. I don't
> >>> know whether shutters of the period operated that fast but, even if
> they
> >>> did, I don't know how it would have been captured on a film emulsion of
> >>> the time.
> >>>
> >>> So, how was this photo taken?
> >>>
> >>> Chuck Norcutt
> >>>
> >> --
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> >>
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