From: phs172m@vaxc.cc.monash.edu.au (Stephen Harker)
Subject: Re: Alaska Class Cruisers
Organization: Physics Department, Monash University, Australia
Date: Tue, 22 Dec 1992 17:27:58 GMT


From phs172m@vaxc.cc.monash.edu.au (Stephen Harker)

In article <BzEyz9.EpG@law7.DaytonOH.NCR.COM>, "david.r.wells" <drw@cbnewsg.cb.att.com> writes:
> 
> From "david.r.wells" <drw@cbnewsg.cb.att.com>
> 
> In article <BzB9L8.zv@law7.DaytonOH.NCR.COM> "david.r.wells" <drw@cbnewsg.cb.att.com> writes:
>>
>>In article <Bz20C9.89v@law7.DaytonOH.NCR.COM> Lee Short <short@asf.com> writes:
>>>"david.r.wells" <drw@cbnewsg.cb.att.com> writes:
>>>>
>>>>OOH! Speculation! Fun Fun Fun Fun Fun!
>>>>I'll put my money on the Alaska. The Alaska actually had better range on
>>>>its 12" guns than the Renown had on its 15" guns. (38,500 yds vs 35,700 yds
>>>>if I remember my Dulin & Garzke correctly) 
>>>
>>>My reference [admittedly not the best, a wargame manual] showed an
>>>even greater disparity (40,600 yds vs. 29,000).  In fact, a majority
>>>of the heavy cruisers produced during the war outranged the Renown.  
>>
>>I'll admit that I used data from the Vanguard for the Renown, but I believe
>>that the Renown got the same 30 degree elevation as the Vanguard had.
>>Perhaps the 29,000 yd range was derived from WWI data, assuming 15 degree
>>elevation? Dulin & Garzke are usually pretty reliable. Which wargame did
>>you get your data from?
>>>
> OOPS! Mea culpa time! I didn't remember my Dulin & Garzke terribly well.
> the 36,700 yd figure for the Renown was from a table which listed elevations
> up to 45 degrees. At 30 degrees, it was 32,100 yds. At 15 degrees, 21,800 yds.
> At 25 degrees, it was 29,300. Perhaps that is the figure used in your wargame.
> But the Renown did have 30 degree elevation. 

	Peter Hodges has the following information (somewhat cut down) for
the British 15" gun:

     max elev   weight	veloc   range
     deg	  lbs	 fps	 yds

15in  20	 1920	2400	23,387 (4crh)
      20	 1938   2575	28,732 (6crh with supercharge)

      30	 1920	2400	28,972 (4crh)
      30	 1938   2400	32,218 (6crh)

So the 29,000 yds range would be for the 15" gun with the old (WW1) less
aerodynamic shell at 30 degrees or for the unmodified guns with 20 degrees
maximum elevation plus a supercharge and the new shell.  The 6crh shell was
introduced between the wars, while the supercharge was used in some of the
old British ships that were not modernised and so still had the 20 degree
maximum elevation.  As you mention the Renown was modernised and had the 30
degree elevation guns.

	Major factors involved in the range are clearly the elevation,
aerodynamic form (crh), speed of shell and its mass.  Newer guns had
greater elevation as well as better aerodynamic shells, I think the KGV
class 14" guns had shells that were 8crh (see Peter Hodges book for
definite information).  On the whole the British preferred heavy relatively
slow shells, the major exception being for the 16" designed for the G3
(1921) battlecruisers and used on Rodney/Nelson though cut down from L50 to
L45.

>-----------------------------------------------------------------------

	The Big Guns - Battleship Main Armament 1860-1945
	Peter Hodges, Conway Maritime Press 1981 (reprinted 1989)
	ISBN 0-85177-144-0
	also US Naval Institute Press 1981

-- 
Stephen Harker			phs172m@vaxc.cc.monash.edu.au
Monash University		Baloney baffles brains: Eric Frank Russell

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