1939 Battleship Forces: US Navy vs Royal Navy

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Garyt
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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby Garyt » Mon May 18, 2015 7:53 pm

... Yamato was comissioned in 1942,
and in the 1939 RN and USN battlelines there wasn't any rangefinder remotely similar in performance to the mammoth 15meters baselength installed on the Japanese battleship.


Longer range finders seems more of an axis thing then i guess. V Veneto class had a 12.5 meter rangefinder, the Bismarck was 10.5m.

Though even though the Yamato was comissioned in 1942, it's radar (and the Japanese radar in general) seemed to be a few years or a generation behind US and British radar.

I believe Yamato's optics actually were head and shoulders above anyone else's


I've heard they were the best optically, the Germans probably second, but was not aware of that great of disparity between the Japanese and the Allies. I guess "How good were their optics?" is not the easiest question to quantify.

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby Garyt » Mon May 18, 2015 7:55 pm

USS Heerman used the rain squall for several succesful surprise attacks this seems to be impossible if the Japanese used radar for tactical purposes.


As Dave said above, even those with blindfire capable radar preferred to corroborate with optics as well.

I must say though, the general hypothesis of this conflict reminds be of Bywaters War, just a decade or two later.

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby Dave Saxton » Mon May 18, 2015 10:25 pm

Thorsten Wahl wrote:
Yamato could have used radar ranging. Although it did not have a firecontrol radar capable of blind fire,

this appears as questionable, when the US CVEs entered the rain squall cease fire was observed.
USS Heerman used the rain squall for several succesful surprise attacks this seems to be impossible if the Japanese used radar for tactical purposes.


Hi Thorsten,

Yamato did not possess radar capable of locating a target accurately enough for bearing to provide blind fire. Hence once the target became shrouded it had to cease fire (in the case of optics only and IF it was using radar ranging in combination with optical bearing). The Japanese were working on a firecontrol radar (Type 32) with fine bearing capability via lobe switching, but they never got it deployed.

The Japanese 10 cm Type 22 radar (which Yamato was equipped with) makes an interesting study. The Japanese 10 cm radar used the same wavelength as Type 274 and Mk8, and Type 273, SG,...ect.... but was not in even the same ball park in terms of performance. The bearing resolution was extremely coarse, being about that of the British 7.5 meter wavelength Type 79 because of the use of such small antenna horns. This coarse bearing resolution would have inhibited its utility for tactical purposes. However, the range accuracy of 100 meters could have come in handy for determining more accurate range to target for long range gunnery, even with the exceptional optical rangefinder gear.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby alecsandros » Tue May 19, 2015 6:15 am

... Visual spoting at 40km does not imply firing at that range. Graf Spee, with an excellent 50x Zeiss optical rangefinder and Fumo23 radar set, and guns with range >36km, did not open fire until 21km.

1939 battlelines would be dependent on doctrine, and available guns and equipment. Most of the guns installed had maximum ballistic ranges of below 30km, and effective ranges below 27km due to elevation limitations (and many below 24km), so firings beyond 19km (70% of range) would have been remarkable, especialy without radar assistance.

British doctrine called for firings between 12 and 17km, and that was the band range for which the battleships and battlecruisers made firing trials.

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby Dave Saxton » Tue May 19, 2015 2:05 pm

alecsandros wrote:...Graf Spee ...and Fumo23 radar set, .


Not to nick pick, but just to set the record straight so errors are less likely to get repeated by future readers: Graf Spee was not equipped with what was later designated retroactively as a FuMO-23. It was designated the DeTe-I and operated on 60 cm instead of 80 cm. :D
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby alecsandros » Tue May 19, 2015 3:50 pm

Dave Saxton wrote:
alecsandros wrote:...Graf Spee ...and Fumo23 radar set, .


Not to nick pick, but just to set the record straight so errors are less likely to get repeated by future readers: Graf Spee was not equipped with what was later designated retroactively as a FuMO-23. It was designated the DeTe-I and operated on 60 cm instead of 80 cm. :D

ok :)

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby Garyt » Tue May 19, 2015 6:23 pm

Most of the guns installed had maximum ballistic ranges of below 30km, and effective ranges below 27km due to elevation limitations


While this is true for those having 15 degree max elevation, the ship with limited to 15 degrees where outnumbered by those with a 30 degree or better elevation, at least in the US Navy.

There were a few that underwent reconstruction in the 30's and one of the changes was their maximum elevation was increased.

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby alecsandros » Wed May 20, 2015 9:00 am

Garyt wrote:
Most of the guns installed had maximum ballistic ranges of below 30km, and effective ranges below 27km due to elevation limitations


While this is true for those having 15 degree max elevation, the ship with limited to 15 degrees where outnumbered by those with a 30 degree or better elevation, at least in the US Navy.

There were a few that underwent reconstruction in the 30's and one of the changes was their maximum elevation was increased.

I was thinking of the some of the British R-class and some QE class, limited to 20* and 23km max range, IIRC.

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby Garyt » Wed May 20, 2015 7:31 pm

I was thinking of the some of the British R-class and some QE class, limited to 20* and 23km max range, IIRC.


Here are some notes on the the 15"/42 gun and mount,the most common battleship weapon for the Royal Navy in this hypothetical 1939 campaign:

During modernizations carried out during the 1930s, Queen Elizabeth, Valiant, Warspite and Renown had their turrets lifted off the ship and sent to the Vickers-Armstrong ordnance works at Elswick for modifications to increase the maximum elevation from 20 degrees up to 30 degrees.


By the mid-1930s the Admiralty saw these guns as growing obsolete, as other nations had developed more powerful weapons, capable of longer ranges and firing heavier projectiles. Along with this, the ships carrying these guns were approaching twenty years of service and starting to show signs of wearing out. Inhibited by treaty restrictions from replacing the battleships, the British instead sought to rectify the situation by initiating a "modernization" program whereby the ships had major overhauls performed and had their weapons upgraded. There were two significant improvements made to these guns during the modernizations: 1) The upper elevation limit of the mountings was increased from 20 degrees up to 30 degrees, which raised their maximum range with 4crh projectiles from 23,700 yards up to 29,000 yards (21,670 m to 26,520 m), and 2) The projectiles were redesigned to add a more streamlined ballistic cap (6crh), which increased the range still further to about 32,000 yards (29,260 m) at 30 degrees elevation. Thanks to these modifications, in July 1940 HMS Warspite made one of the longest hits ever scored by a naval gun on an enemy ship when she struck the Italian battleship Guilio Cesare at approximately 26,000 yards (23,770 m).


The rate at which these ships could be modernized was limited and by the start of World War II Malaya, Barham, Repulse and the five Royal Sovereign class battleships had not yet been upgraded. Royal Oak, Barham and Repulse were sunk early in the war, but the remaining unmodernized ships were given a "Super Charge" which consisted of the largest possible propellant charge that the guns and mountings could safely handle. These were issued starting in late 1941 and at the maximum elevation of 20 degrees allowed a range of 28,700 yards (26,240 m). However, from a study of the records, it would appear that no ship ever fired a shot using Super Charges, although they were used by the coastal artillery at Dover. Super Charges were not issued to ships with 30 degree mountings as the increased barrel wear and mounting stress was not considered to be acceptable. For this reason, sources which quote HMS Vanguard as having gun ranges in excess of 32,000 yards (29,260 m) are somewhat misleading, as such a range would have required the use of super charges, which she never carried.


The Hood MK II mounts already were capable of a 30 degree elevation from their inception.

Here are the ranges based upon elevation with the streamlined projectile (which would have been used in 1939) and normal charge:

2.6 degrees -5,000 yards (4,570 m)

5.6 degrees- 10,000 yards (9,140 m)

9.3 degrees- 15,000 yards (13,720 m)

13.8 degrees- 20,000 yards (18,290 m)

19.2 degrees-25,000 yards (22,860 m)

26.1 degrees-30,000 yards (27,430 m)

30.5 degrees-32,500 yards (29,720 m)

So it looks like in the British Navy as well, the amount of guns capable of a 20 degree elevation would be about 50/50 with guns capable of a 30 degree elevation, as Hood, Rodney and Nelson also all had 30 degree capability.

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby alecsandros » Thu May 21, 2015 5:40 am

alecsandros wrote:I was thinking of the some of the British R-class and some QE class, limited to 20* and 23km max range, IIRC.

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby Garyt » Thu May 21, 2015 6:33 pm

I was thinking of the some of the British R-class and some QE class, limited to 20* and 23km max range, IIRC.


Good point

I guess I was in essence re-iterating your comment. :D

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Re: 1939 Battleship Forces: US Navy vs Royal Navy

Postby alecsandros » Thu May 21, 2015 6:58 pm

Garyt wrote:
I was thinking of the some of the British R-class and some QE class, limited to 20* and 23km max range, IIRC.


Good point

I guess I was in essence re-iterating your comment. :D

:)
I was thinking that quite some BBs from the 1939 battleline could not shoot further than 25km, and that would imply a much smaller effective range.

It would be amazing if fire was opened before 20km.


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