Re: BB & 18-in. Gun Tubes (Response)

[<geminiad@whidbey.com>]

To All,

> MUSHASHI is the correct name for "Yamato" BB, second ship of the class..

Mushashi was laid down at Mitsubishi Yards, Nagasaki on March 29, 1938.

During Battle of the Leyte Gulf action, she formed part of the Central
Group
battle force, which departed Brunei on October 22, 1944. 

Subjected to a long-range carrier based Navy air attack from 8 carriers 
on October 24th,  the Mushashi was mortally damaged - hits 
 included 20 torpedo and 17 bomb hits, the ship  at 1915 hrs had
a 12-deg. list to port and was failing to respond to the helm,
eventually
foundering. Abandon ship was ordered at 1920 hrs.

> SHINANO was originally  "Warship No. 110"  - or thrid ship
of the "Yamato" class.  Battleship was laid down at Yokosuka Navy
Yard on May 4, 1940, built in Drydock No. 6.

The decision to convert the ship from a battleship to a large carrier
was the result of war's initiation in December 1941. For a 62,000 ton
ship, she could only accomodate a relatively small air group of 47
aircraft.
There were but two decisions considered : scrap the hull as thus far 
completed; or] convert the upper hull area to an aircraft carrier.

The ship was commissioned November 19, 1944 but still lacked four
boilers intended for the ship.  She was attacked after departing
Yokosuka
for Kure to load the air group, on Nov. 29th , by USS Archerfish
(SS-311).
No doubt the result of U.S. SIGINT and "5-Num" naval code intercepts.  

Six torpedoes were fired  and four struck the ship. 
Starboard forward oil storage bunker and air compressor  room and  					
and boiler room No.3 were flooded  by the first two hits; 
starboard outer Engineering Room was flooded by
hit #3 and a starboard stores room and gasoline storage bunker were
flooded
by hit #4.  Had 70-75% of the crew not been recruits and not previously
seeing 
action, the ship probably would have survived -  subsequent failures in 
damage control doomed the ship.

Because of the wars progress against Japanese resources and demands
on the shipbuilding industry, the origional projected battleship
completion
date was not far from the actual November '44 date; but resources for
completion of another battleship were viewed as better devoted to 
carriers and destroyers than battle wagons. Given the growing shortage
of
fuel oil by late '44, it would have made little difference if the ship
was 
built as a BB or CV, ultimately. 

Had greater priority been given to the ship, it might have commissioned
in time for participation in the Battle of Leyte Gulf, but whether it
would
have contributed successfully to some outcomes of the battle is
problematical - either as a BB or  CV..  

Was the beach debris from Shinano? Some may have been but it was
not uncommon to leave shipbuilding debris around areas not likely to
be attacked from the air and to remove them from the immediate dockyard
construction area when not needed.

> Warship No. 111 -  This ship was never  named.

Also laid down in November 1940 - after the launching of Yamato. Ship
would
have resembled the Shinano, with modified 6.1 inch gun turrets and other
modifications proposed after Yamato design was approved. 

Primary armament would still have been the 18.1"/45cal (460mm) guns 
- 						three triple turrets. 
Shell weight: 3,219-lbs (1460-kg.)
Muzzle velocity: 2,559 ft/sec (780 mteters/sec)
Range: 45,275 yards (41,400 meters)

>  Future BB Programs -  

The IJN did have pre-war plans for expansion of the "Yamato" class,
and under the Fifth Fleet Replenishment Program (Fiscal 1942) -
"Maru Go Keikaku" -  three  further hulls were planned, as Warship No.
797, 798, 799. 
These were considered "Improved Yamato" class ships, with 2 x wing 6.1
in turrets
removed and new  twin 3.9in. automatic AA turrets substituted and number
of such mounts increased to 24 on the design. Same design as used
on the Type B / "Akisuki" fleet destroyer.

The 6th Fleet Plan envisioned another 4 super-battleships -with 8 x
20-inch
main guns in four twin turrets and potential displacement as high as
100,000
tons (comparable with "Nimitz" CVN today).  This dream fleet would have
ten comprised 19 BB, 20 CV, and 43 cruisers (incl. 2 x battlecruisers). 

> Future Plan, January 1941.

As the IJN envisioned future strategy, it was fundamental that their 
battleships be superior in quality over a future American fleet. By 
mid-January 1941, this translated to a future fleet (1950)  6 BB
Divisions
comprised into 1st, 2nd, and 3rd Fleets (Reserve) - latter only being
IJN Kongo and Haruna (other two of class retired by this date).

Had the war not broken out until 1945 as some envioned in Tokyo,							
Japan would have had 4 Yamato BB completed by late-44 and a 
further 7 under construction. 

This would have comprised a fleet of 11 battleships - 4 with 18.1 inch
guns -
against an American fleet of 17 new battleships with 16 inch guns -
comprising the "North Carolina" through "Montana" classes. Not all 17
would be completed by that date either, the USN likely to have only 
three "Iowa"  + 3 building + 5 "Montana" building.

When the US Navy passed the "Two Ocean Navy" program  -
Part I (CNO 20 May 194) approved 3 CV's (No. 9, 10, 11 Essex class) -
11% Expansion
Part II (CNO 16 Aug 1940) approved 7 BB (BB-65 - 71), 
	 6 large cruisers 	(CB, Alaska class) and 
	7 CV (CV-13-19)  - 70% Expansion act.

In both the USN and IJN, the battleship admirals were still in charge in
1940-41.
The original contract awared for USS Essex (CV-9) did not have
compleetion
until April 15, 1944 !  Had  peace prevailed until 1945, the USN would
have
had but 3 "Essex" CVs completed - and a whole lot of battlesships coming
!
Can Japan's planners be falted so heavily in '40-41 was such thinking.

[Good source on US Navy carrier development up to this period  is:				
"American & British Aircraft Carrier Develoopment, 1919-1941" by
T. C. Hone, Norman Friedman & M.D. Mandeles [ USNI Press, 2000].

> BB Development Source - 

Best single source is: "Battleships, Axis and Neutral Battleships in
World War II" by William H. Garzke and Robert O. Dulin  [USNI Press,
1985]
--------
Part II will follow ref 16" and 18.1" gun development......

Keith Jacobs