British BL 18in/40 gun

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Re: British BL 18in/40 gun

Post by Bgile » Sat Oct 03, 2009 9:59 pm

My thinking was that if you have two spashes and they are far apart, you don't know which one was an error. With three, if one gun is mismatched you will usually have two together and the bad third one is obvious. You get even more insurance with four.

With regard to radar targeting, I have this quote from Capt Ben W. Blee, USN (ret), the USS North Carolina Intelligence officer. He was discussing the process of coaching the main battery FC director onto a surface search radar target:

"We became so proficient at it that at ranges of as much as 35,000 yards, day or night, we were confident of our ability to open fire and straddle the target with our first salvo. We were capable of doing this within two or three minutes after initial radar contact".

This is one of the reasons I make these claims of the superiority of radar assisted fire that Karl likes to make fun of.

With regard to getting "on" for line, I'm sure I've seen a quote from someone on Bismarck stating that they were usually on for line with their very first salvo and opened with a ladder ... 12 shells, 4 from A&B, then 4 from C&D, then 4 from A&B again, all before the first salvo hit the water. I don't know whether they always did it this way; it was not an official log or anything like that.

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Karl Heidenreich
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Re: British BL 18in/40 gun

Post by Karl Heidenreich » Sun Oct 04, 2009 12:34 am

Both of them, R&R and G&D (but specially R&R), are very clear that the gunnery experts (at least the British and German ones) preferred the twin turret over any other arragement. In the R&R book that is quite clear and specific to the quote. Sadly as I said my R&R is now in Costa Rica and I got here Garzke and Dullin. However before doing a direct quote from G&D in this regard I will quote myself (if I´m allowed to do that) from a previous post of the Bismarck and her Contemporaries thread which is obvious was not read or simply ignored:
The design comprised of two quadruple turrets and one twin turret. For the Naval Staff and the DNC the optimum arrangement was four twin turrets which was what the artillery experts recommend. The war lessons and the “ladder” firing principles called for a four turret design that the Germans were already using in their Bismarck Class. Anyway the 14” of the KGV Class were based in the successful twin gun mountings and Vickers twin gun mountings. One of the issues that the quadruple mountings presented was a severe complexity of the interlocks (at least compared to the twin 15”) because of the need of made them as flash tight as possible.
That´s a summary of the comments from R&R. Now, using a direct quote from a very good source that it´s quite critical to the German design and Bismarck in particular we have this from G&D, page 13:
...For ships designed after the naval holiday, the treaty displacement limitations, coupled with pressures for higher speed and improved horizontal and underwater protection, led to many weight saving expedients... However, more weight savings were possible in the adoption of the triple or quadruple turret because more guns could be carried per total turret weight and the armor of the citadel could be reduced in lenght... German rejection of the triple turret in the Bismarck and Tirpitz, despite its success in the Schanhorst and Gneisenau, emphazised a widely held conviction that twin turrets permitted more effective gunnery with greater dispersion of the main battery and relatively added displacement
The previous statement from G&D echoes hard with R&R´s one. It is clear, in any case, that the adoption of triple and quadruple turrets do not obey to any qualitative criteria but to that of a weight saving to abide the treaty impositions. From R&R we have a precise and unavoidable idea that if the British could have avoided the triple and quadruple turret they would have done it! It is clear that the Nelsons with their triple 16" turrets was very dissapointing to them to the degree that the Naval Staff and the DNC were adamant in not use it never again.

It is also clear that both, Friedman and R&R warn about the concentration of firepower in less turrets. Statiscally this procedure puts at risk the overall firepower of the ship being the Richelieus the ones with the extreme case of this "issue" (the word "flaw" can only be applied to Bismarck).. to this "flaw". Both, Friedman and R&R, mentioned, specifically this. And for the time being everrybody seem to be keen to ignore this. As they have been ignoring quote after quote that I have been bringing with evidence that many prejudiced criteria has no solid footing.

Please read the information that I have been bringing forth, since the Yamato vs. Iowa thread which is rich in order to see the other side of the coin. Let´s be more intelectually open!

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Re: British BL 18in/40 gun

Post by Bgile » Sun Oct 04, 2009 1:23 am

Karl Heidenreich wrote:It is clear that the Nelsons with their triple 16" turrets was very dissapointing to them to the degree that the Naval Staff and the DNC were adamant in not use it never again.
We all know why the Nelson arrangement had problems.

Now please explain why the British planned to use triple turrets in the Lion class, since "the Naval Staff and the DNC were adamant in not use it never again".

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Re: British BL 18in/40 gun

Post by Karl Heidenreich » Sun Oct 04, 2009 2:24 am

Now please explain why the British planned to use triple turrets in the Lion class, since "the Naval Staff and the DNC were adamant in not use it never again".


They had no other choice at that time. But in their design exercises the twin turrets were considered. If we read carefully the last Conference allowed for an escalation up to 45,000 tons which the USN used for the Iowas. The British self imposed themselves, because of restrictions in their docks and ports, to the 40,000 tons. That still calls for a bit of weight economy. The triples help on that.

Triples that were of a complete different nature of those used by the Nelsons. Triples that were never finnaly produced, by the way.

Now please, please: let´s read the sourced information (which is blatantly ignored) and discuss on it.

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Re: British BL 18in/40 gun

Post by tommy303 » Sun Oct 04, 2009 3:20 am

Bgile,
"We became so proficient at it that at ranges of as much as 35,000 yards, day or night, we were confident of our ability to open fire and straddle the target with our first salvo. We were capable of doing this within two or three minutes after initial radar contact".
I believe at this time the Washington had SG search radar and the Mk 4 gunnery radar sets. The latter could range on a battleship at about 28,000 yards and spot to about 20,000. The SG on the other hand could detect a battleship at 40,000 yards and range on it at about 35,000. What I suspect the officer in question was saying was that they used the SG, once it detected an enemy vessel, to bring the directors onto target. Although range accuracy of the SG was probably a little less than the Mk 4 gunnery sets, it was still vastly superior to optical means of range finding and first shot acquisition of the target would have been easier. Later when the Mk 8 Mod 0 and Mod 1 became available, it was no longer necessary for SG radar to be used to help direct the main battery, as the Mk 8 could range to over 35,000, though it was still unable to spot to that range; this let the SG get on with its primary role of search independent of the gunnery problem. The 1945 Mk 8 Mod 3 and the similar Mk 13, also introduced in late 1945 could also spot to 35,000.

That said, the quote shows how effective and flexible US radar doctrine became during the course of the war.
My thinking was that if you have two spashes and they are far apart, you don't know which one was an error. With three, if one gun is mismatched you will usually have two together and the bad third one is obvious. You get even more insurance with four.
That is very true.

For Karl,

The use of twin turrets entail the advantages you mention, of course, and they allowed for smaller diameter barbettes and openings in the decks to accommodate them, but there are also a few disadvantages besides the need for a longer citadel if you use four twins instead of three triples. One was shell wave and blast interference. In the former, if one had a shell which left the muzzle slightly after its partner from the other barrel, the slower, trailing shell could find itself flying through the turbulent air in the wake of the the shell ahead of it. This causes more drag, resulting in less range and the shell falling shorter than its partner. With two guns, relatively close together, muzzle blast could also affect one or both shells by inducing a slight amount of yaw over that normally inherent in spun cylindrical-conoidal projectiles. This in turn creates more drag and will cause the affected shell to fall shorter than its companion. Finally, if the barrel axis are not exactly aligned (in US service alignment was normally within .5 degree) two shells leaving the muzzles at the same time with the same velocity could touch somewhere down range. While rare, such events, known as kissing, have been observed through binoculars.

There were several ways around these phenomenon. One was the British salvo method with twins where one salvo was fired with the right barrels of all turrets able to bear on the target, follow at an interval by the left barrels as the right ones reloaded. Thus alternating salvos could be fired in a steady manner without any interference between guns or shells. In German turrets the guns could be elevated independently, but the ammunition hoists arrived in the gun house at the same time and were not independent. This pretty much dictated why the Germans fired in turret group salvos instead of all right and then all left guns (at least in their WW2 twins). To get around interference, delay coils were incorporated so that the guns in a turret did not fire at the same time.

This solved the interference problem but created another one in twin turrets. This was turret whip where the off center recoil of one gun could cause the turret to whip slightly if there was any play in the training mechanism, just as the delay coil fired the second gun. This created a situation where the lateral spread of shot was increased slightly, and might explain in part the slightly longer lateral dispersion pattern noted in German salvos. In triples, where the delay coil was used in the centre gun and the two outer barrels fired together, whipping did not occur.

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Re: British BL 18in/40 gun

Post by Karl Heidenreich » Sun Oct 04, 2009 12:38 pm

tommy303:

Thanks for the additional information on this issue of the turret arragement. Now I do understand much better certain comments done in the bibliography I´m using and that were a bit obscure.

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Re: British BL 18in/40 gun

Post by Bgile » Sun Oct 04, 2009 2:34 pm

Karl Heidenreich wrote:
Now please explain why the British planned to use triple turrets in the Lion class, since "the Naval Staff and the DNC were adamant in not use it never again".


They had no other choice at that time. But in their design exercises the twin turrets were considered. If we read carefully the last Conference allowed for an escalation up to 45,000 tons which the USN used for the Iowas. The British self imposed themselves, because of restrictions in their docks and ports, to the 40,000 tons. That still calls for a bit of weight economy. The triples help on that.

Triples that were of a complete different nature of those used by the Nelsons. Triples that were never finnaly produced, by the way.

Now please, please: let´s read the sourced information (which is blatantly ignored) and discuss on it.

Best regards,
Of course the new British triples were never produced. The class was cancelled. US triples worked just fine. As far as I know, so did IJN, Italian, and German triples.

Weight economy is ALWAYS important. It's important in a 40,000 ton design and it's important in a 65,000 ton design and it's important in a 95,000 ton CVN. You never get away from that. The USA continued to use triple turrets in CA's right through the war and when they designed the automatic guns for the Salem class they used triple turrets for them as well. The British used triples in their new CLs. Wartime experience didn't cause them to go to twin turrets. Sometimes twins are appropriate and sometimes triples are. It has nothing to do with whether you have more design experience.

The biggest reasons Bismarck had a higher weight devoted to armor than anyone else are:

1. The four turret design. Total turret weight was greater and the citadel had to be longer.
2. The unnecessarily thick armor protecting the sides above the Panzerdeck. Too thin to do more than fuse battleship shells and just added a lot of weight.

What is the sourced information I'm blatantly ignoring? I really don't know what you are talking about there.

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Re: British BL 18in/40 gun

Post by Karl Heidenreich » Sun Oct 04, 2009 5:19 pm

The German triples worked just fine as G&D regard in Schanhorst and Gneisenau, but even then they went, for the bigger battleships Bismarck and Tirpitz, back all the way to the twin mountings. Also, if we read carefully my previous post it becames evident that the British would have returned to the twins if possible. Weight saving issues deterred them to do so.

About all other issues regarding Bismarck I hope that I could dealth with them in the thread from Bismarck and her Contemporaries, which is why it is there.

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Re: British BL 18in/40 gun

Post by RF » Mon Oct 05, 2009 7:47 am

I still don't find the arguments for twin mountings over triples convincing. for me maximizing firepower for a given weight would be key.
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Re: British BL 18in/40 gun

Post by lwd » Mon Oct 05, 2009 4:43 pm

Bgile wrote: ...The biggest reasons Bismarck had a higher weight devoted to armor than anyone else are....
My understanding was that the biggest reason was the way in which the Germans calculated the armor weight.

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Re: British BL 18in/40 gun

Post by Karl Heidenreich » Sun Oct 11, 2009 2:51 am

I just read that Hitler asked Raeder to consider the mounting of a Gustav like gun of 800mm (31,5") in the new BBs. It seems that Raeder had a hard time explaining Hitler that a ship to carry such a gun would have been imposibly big, at least bigger than the H 44 if such a thing was possible.
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Re: British BL 18in/40 gun

Post by lwd » Sun Oct 11, 2009 4:44 am

The one fault no one can legitimately accuse Hitler of was "thinking small".

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Re: British BL 18in/40 gun

Post by Brad Fischer » Sun Oct 11, 2009 3:12 pm

tommy303 wrote: I believe at this time the Washington had SG search radar and the Mk 4 gunnery radar sets. The latter could range on a battleship at about 28,000 yards and spot to about 20,000. The SG on the other hand could detect a battleship at 40,000 yards and range on it at about 35,000. What I suspect the officer in question was saying was that they used the SG, once it detected an enemy vessel, to bring the directors onto target. Although range accuracy of the SG was probably a little less than the Mk 4 gunnery sets, it was still vastly superior to optical means of range finding and first shot acquisition of the target would have been easier. Later when the Mk 8 Mod 0 and Mod 1 became available, it was no longer necessary for SG radar to be used to help direct the main battery, as the Mk 8 could range to over 35,000, though it was still unable to spot to that range; this let the SG get on with its primary role of search independent of the gunnery problem. The 1945 Mk 8 Mod 3 and the similar Mk 13, also introduced in late 1945 could also spot to 35,000.

Actually that’s not correct regarding spotting range and the Mark 8 Mod 1 (and later). BuOrd listed the max reliable spotting range for the Mark 8 Mod 1 as 30,000yds because when they were conducting their formal testing of the Mod 1(with Wisconsin) the weather was such that they couldn’t satisfy the optical safety checks to conduct the run at 35,000yds. BuOrd usually provided a caveat, such as in OP 658 (Mark 8 Mod 1/2 radars) that the radar could spot 16-inch AP to at least 30,000yds and noted that several reports to the fleet indicated spotting was obtained to 35-36,000yds.

Our own research for the Fast Battleship Gunnery article in W.I. we found eleven instances of fire beyond 30,000yds -- all but one with reliable spotting -- and 4 out of 5 at 35,000yds. Of those 5 at 35,000yds, all but one were calibration shoots that employed single gun salvos. This is significant because there is a marked tendency for reliable spotting range to increase as salvo size increases. Alabama noted in an October 1943 report that spotting to maximum gun range was possible with 6 or 9-gun salvos from the forward Mark 8 installation.

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Re: British BL 18in/40 gun

Post by tommy303 » Sun Oct 11, 2009 4:10 pm

I stand corrected.
This is significant because there is a marked tendency for reliable spotting range to increase as salvo size increases
Presumably this is because the radar return for a larger salvo is stronger than with a single shot?

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Re: British BL 18in/40 gun

Post by Dave Saxton » Sun Oct 11, 2009 7:43 pm

Bgile wrote:
With regard to radar targeting, I have this quote from Capt Ben W. Blee, USN (ret), the USS North Carolina Intelligence officer. He was discussing the process of coaching the main battery FC director onto a surface search radar target:

"We became so proficient at it that at ranges of as much as 35,000 yards, day or night, we were confident of our ability to open fire and straddle the target with our first salvo. We were capable of doing this within two or three minutes after initial radar contact".
.
Steve, what time period is this?
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