Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!att!cbnews!military
From: welty@lewis.crd.ge.com (richard welty)
Newsgroups: sci.military
Subject: Just Mortars
Summary: was Re: Mortars & Tanks (and tracers)
Message-ID: <8481@cbnews.ATT.COM>
Date: 21 Jul 89 04:09:44 GMT
References: <8033@cbnews.ATT.COM>
Sender: military@cbnews.ATT.COM
Organization: New York State Institute for Sebastian Cabot Studies
Lines: 65
Approved: military@att.att.com



From: welty@lewis.crd.ge.com (richard welty)

In article <8033@cbnews.ATT.COM>, pierson@cimnet.dec.c writes: 
*Historical interlude: ca 1890/1900 "seacoast mortars", typically around 12",
*were popular for coast defense.

12" sounds a bit high.  4.2" was very common.  the only 12" seacoast
defense weapons i know of were guns, sometimes on a `disappearing' mount
(the gun was on a lever arm mounting and the recoil would drop the gun
behind a revement where it would be reloaded.)

[mod.note: A quick perusal of _Weapons of the Third Reich_ shows a 28cm
Ku:stenhaubitz (coastal howitzer) which is essentially a mortar, left from
pre-WWI, and a similarly-dated impressed  French 27cm coastal mortar.  Seems
large mortars were around at the time. (28cm = 11")  - Bill ]

at Ft. Desoto park, just south of St. Petersburg, Florida, a 4.2"
battery of mortars has been preserved in fairly good condition.
the fort is actually a very representative sample of the kinds of
coast defense installation that the US was building on all of its
possessions at the time.  there is a twin fort on the other side
of the shipping channel on Egmont Key; there is no surface access
to the key, and no effort has been expended on preserving this
installation.

the earliest 4.2" mortar installations grouped 4 such weapons
into each bay of a fort; the concussion of simultaneous firing
was such that the crews were incredibly abused; later installations
went to 2 guns per bay.  the watervliet arsenal has a nice picture
of a 4 gun/bay site; they are trying to find one of the mortars for
their collection but have so far been unsuccessful.

*  The objective was to shells drop onto the
*lightly (some times un) armored deck of battleships, etc.

it was only during wwi that ship designers realized that
with increasing angles of elevation on the main batteries
of ships, that the distances of engagement would increase,
which would therefore make plunging fire an issue.  post wwi
designs were much less vulnerable to this type of coast defense
weapon.

and now for a question: until i toured the arsenal museum last
saturday, it had never occured to me to think about recoil and
mortars.  the 4.2" coast defense weapons had no particular
provision for recoil, and the stress on the mounting and the
concrete foundation underneath must have been tremendous.
one of the museum staff informed me that an 81mm mortar
recoils with a force of 400g's; i guess that all of this is
handled by the large baseplate.  are there any mortars with
special provisions for recoil, or is this considered an
unnecessary frill?

richard

[mod.note: From the same source, I note a number of recoil-compensated
mortars.  These include a 5cm model designed for Stalingrad street-
fighting and a large 15cm (6") model.  Neither was successful.  - Bill ]
-- 
richard welty               welty@lewis.crd.ge.com
518-387-6346, GE R&D, K1-5C39, Niskayuna, New York
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