KGV Class Battleships

Warship design and construction, terminology, navigation, hydrodynamics, stability, armor schemes, damage control, etc.
dunmunro
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RPC in the SoDaks

Postby dunmunro » Tue May 25, 2010 12:06 am

Early in 1943 when we ran around the Coral Sea with the North Carolina and Saratoga, we had a problem with the hydraulic power drives on the 5 inch gun mounts when they were put into automatic they would oscillate wildly. At one time we had seven out ot the ten mounts acting up. C.P. Royce at that time 2nd class fire controlman (called home La Jolla, CA I believe) DeRose (Fairmont, WV) S1c at that time and myself, also S1c worked with the gunners mates tearing into the system searching for the problem. The oil was drained and we took apart the receiver regulators and cleaned the fine pilot pistons with pink lady (alcohol rendered unfit for drinking) it didn't work, it left a pink film on the valves and shortly the mounts again began to oscillate. Royce decided we needed pure grain alcohol to clean the valves. Gannarelli at that time a Warrent Gunner was custodian of the alcohol and was probably reluctant to release any but we finally got a little and it did not work either. No one drank any either, to the best of my knowledge. Well, finally a factory represenative from Ford Instrument Co. was flown out there (Neumea, New Caledonia) and he discovered the oil was contaminated with an acid. The gunner mates drained the oil and we recleaned the valves and new hydralic oil was put into the drives with no more problems with oil.
Whitner Livingston Griffin, Jr., Fire Controlman 1c, FA Division

http://ussindianabb58.com/remembrances/ ... nces1.html

When I went aboard in Newport News or Norfolk, (I don't remember which), I was assigned to the Sixth Division, and was assigned to Mount 10 where I spent my entire cruise the next four years or more. The Chief Gunners Mate over me and I got along pretty well as I had pretty extensive hydraulic equipment experience prior to the Navy so I had plenty to keep me busy the first few months. On those 5" twin mounts the control valves and hydraulic motors were mounted in the girders below the mount deck which meant all of the valve blocks and motors had to be worked on from the upper ammo handling room deck. This meant every hydraulic motor and valve block was over your head and oil, that is free oil, always runs down hill which meant to me that I probably drank more hydraulic fluid than I ate beans for breakfast. When you work on any Navy equipment you are extremely limited as to what you can do or not do to correct any problems. These five inch guns were primarily AA batteries. The upper hoists for the shells had to be very exacting in their operation and I had a couple of hoists that did not want to operate that way. They would continually fail to stop until the jumped the detent latch and that would mean that the gun was out of business until I could get down off my mount captains perch or stand and back them up by hand to put them in firing order again. The Gunnery Officer would not let me increase to a heavier size spring so I had that problem whenever we fired AA fire. In fact I spent the entire time on the shake down cruise to Maine working on that problem. When we left Virginia for Panama I had one hoist apart and unworkable.

http://ussindianabb58.com/remembrances/ ... nces5.html

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Re: KGV class

Postby Bgile » Tue May 25, 2010 12:53 am

Of what relevance is the above? I had lots of problems I had to fix when I was in the Navy, some of them exasperating. It was good gear though, and once we found the problem and fixed it it worked well. Very little equipment is trouble free, especially new installations. This is one guy's vexing problem with his gear. We already know the rpc for the 5" guns had hunting problems early on.

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Re: KGV class

Postby dunmunro » Tue May 25, 2010 2:13 am

Bgile wrote: Very little equipment is trouble free, especially new installations.


Exactly. RPC and the automated hoists with integral fuse setters sound like great innovations, and eventually, they were. However, this doesn't mean that fresh from the builders that a BB equipped with such a system will out perform a system with FtP FC and conventional fuze setting trays.

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Re: KGV class

Postby Bgile » Tue May 25, 2010 4:04 am

dunmunro wrote:
Bgile wrote: Very little equipment is trouble free, especially new installations.


Exactly. RPC and the automated hoists with integral fuse setters sound like great innovations, and eventually, they were. However, this doesn't mean that fresh from the builders that a BB equipped with such a system will out perform a system with FtP FC and conventional fuze setting trays.


Well, those hoists had been in service for a number of years at that point.

I used to do trials certification on SSNs. There were always all kinds of problems, but if you look at a boat of the same class that had been in commission for several months, the problems were all gone.

dunmunro
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Re: KGV class

Postby dunmunro » Tue May 25, 2010 5:00 am

Bgile wrote:

Well, those hoists had been in service for a number of years at that point.

I used to do trials certification on SSNs. There were always all kinds of problems, but if you look at a boat of the same class that had been in commission for several months, the problems were all gone.


I've read enough to know that the USN experienced a lot of difficulty with their RPC FC systems, and the fact that Indiana was still having major problems in early 1943 simply reconfirms what I've read previously.

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Re: KGV class

Postby Bgile » Tue May 25, 2010 5:25 am

dunmunro wrote:I've read enough to know that the USN experienced a lot of difficulty with their RPC FC systems, and the fact that Indiana was still having major problems in early 1943 simply reconfirms what I've read previously.


All we know is that one technician was having troubles on Indiana in early 1943.

Your statement is all inclusive. All I know about is some problems with 5" guns in RPC. The 40mm Bofors used RPC, and they shot down a lot of aircraft. The British used it as well. How bad could the problems be?

What does this have to do with the fuse setters in the hoists? As far as I know, they were relatively trouble free.

I'm guessing that if you looked into the lives of British maintainers during the war you would find a few with serious maintenance problems to deal with. For some reason, we don't hear about them. A read of the pom-pom problems during the loss of force Z is instructive. IIRC one 8 gun mount on Repulse had one gun firing.

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Re: KGV class

Postby dunmunro » Tue May 25, 2010 8:41 am

Bgile wrote:
All we know is that one technician was having troubles on Indiana in early 1943.

Your statement is all inclusive. All I know about is some problems with 5" guns in RPC. The 40mm Bofors used RPC, and they shot down a lot of aircraft. The British used it as well. How bad could the problems be?

What does this have to do with the fuse setters in the hoists? As far as I know, they were relatively trouble free.

I'm guessing that if you looked into the lives of British maintainers during the war you would find a few with serious maintenance problems to deal with. For some reason, we don't hear about them. A read of the pom-pom problems during the loss of force Z is instructive. IIRC one 8 gun mount on Repulse had one gun firing.


I know that the RN had problems with RPC as well, but also that the RPC used on the Bofors mount, which, IIRC, was derived from UK (Admiralty Research laboratory) technology used by the British Army for the Kerrison Predictor ( http://en.wikipedia.org/wiki/Kerrison_Predictor ) , did not use the USN RPC system and was pretty much free from the problems in the other USN RPC systems. I have commented adversely on the RN Hazemeyer system in the past.

If the hoists aren't working, then neither are the fuse setters...

Despite the defective ammo, Repulse's pom-poms still shot down two aircraft. Technically, PoW's CIWS was far superior, but it proved more fragile, and it failed to perform up to the same levels as it had in Aug/Sept 1941 during Operation Halberd. Why this was the case, has never been adequately explained, IMHO.

The point, again, is that it is wrong to assume that because a particular system appears to be technologically superior, that in actual service, that it was. The RN needed robust systems that could work with minimal maintenance under very adverse conditions, and it took the USN some time, which was a luxury the USN had, to work out the bugs, but the RN was in the thick of it from 1940 onward and the same kinds of problems would have been catastrophic. I'll quote from Mindell again:

However useful and innovative, this feature exceeded the limits of BuOrd’s or its contractors’ technical knowledge. The feedback loop on the Mark 37,“a previously untried closed-circuit servo,” had a stability problem: the output of the computer moved the director, which in turn affected the input to the computer. Both the computer and the power drives had time lags, so the two could push and pull each other and make the system oscillate. How these loops interacted and fed back on each other was poorly understood and caused severe problems in operations. When radar was added in the equipment was already in production, and the navy was preparing for war. The noisy, often erratic signals instigated a complete breakdown. But The stability problem in the Mark 37 was the most prominent example of a complication arising throughout naval fire control. Wherever sensitive instruments and intricate computers drove powerful servos on heavy gun mounts the systems could become unstable.“It is well known,” a 1937 report read, that “the guns, because of their enormous inertia, do not respond instantaneously to a signal from the director . . . for similar reasons the guns tend to swing too far when coming to alignment with the director after such motion, giving rise to ‘hunting’ or oscillations.” Adjustments could make these systems stable, but only at the cost of unacceptably degraded performance. A series of tests identified an “inherent weakness”in the Ford system of control and in the hydraulic speed gear with which it was used. BuOrd’s precious machines suffered from “insufficient ‘stiffness’ or ‘rigidity’ or a lack of prompt response to the director system.” Naval fire control systems, for all their precision, ruggedness, and sophistication, had run up against a problem the engineering culture could not solve: how to make a feedback loop move a large mass at high speed without making it unstable. Solving this problem required more theoretical analysis than the engineering culture of fire control could provide, so the navy turned to institutions that had developed different types of knowledge about feedback, including Bell Labs and MIT.

Mindell, David A. Between Human and Machine : Feedback, Control, and Computing before Cybernetics.

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Re: KGV class

Postby Bgile » Tue May 25, 2010 1:30 pm

In 1937. And no reference to problems with the 40mm Bofors hunting, with years of use from 43 on. And hundreds of references to the 5"/38 firing thousands of rounds of ammo against all kinds of targets and nothing about hoist problems. And you find one guy who had a problem with a hoist and all of a sudden the system doesn't work anymore. References to using the Mk51 with Bofors and with 5" and how that corrected some of the problems with rapid engagement of aircraft, and nothing about it not working because the weapons "hunted". You just have this continuous barrage of things ... very few weapons are trouble free when introduced.

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Re: KGV class

Postby dunmunro » Tue May 25, 2010 8:22 pm

Bgile wrote:In 1937. And no reference to problems with the 40mm Bofors hunting, with years of use from 43 on. And hundreds of references to the 5"/38 firing thousands of rounds of ammo against all kinds of targets and nothing about hoist problems. And you find one guy who had a problem with a hoist and all of a sudden the system doesn't work anymore. References to using the Mk51 with Bofors and with 5" and how that corrected some of the problems with rapid engagement of aircraft, and nothing about it not working because the weapons "hunted". You just have this continuous barrage of things ... very few weapons are trouble free when introduced.


I stated ealier:
"I know that the RN had problems with RPC as well, but also that the RPC used on the Bofors mount, which, IIRC, was derived from UK (Admiralty Research laboratory) technology used by the British Army for the Kerrison Predictor ( http://en.wikipedia.org/wiki/Kerrison_Predictor ) , did not use the USN RPC system and was pretty much free from the problems in the other USN RPC systems."


The USN appears to have ironed out the problems in their RPC systems by the late war period, but I know that this was not the case in 1942.

Our training schedule took on more importance and the tempo picked up. As Assistant Gunnery Officer, I attended the Gunnery Officer’s School held on DIXIE once a week and heard the Squadron Gunnery Officers expound on the arcane art. One could read all about the technical details of our guns and firecontrol in the manuals, but hearing how to handle the equipment from the best in the fleet brought it all to reality. Automatic Gun Drives were still new in the Fleet and were plagued with reliability problems. The intricacies of the Mk-10 Rangekeeper were baffling to most officers. I found it all fascinating and listened with relish.
http://www.destroyerhistory.org/goldplater/crest01.html

A proper history of RPC has yet to be written.

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Re: KGV class

Postby alecsandros » Wed May 26, 2010 10:54 am

A side note: German RPC was well functioning from 1941. Bismarck used it with the known results in the engagements 24-26th of May.
The Royal Navy introduced it on HMS Vanguard ~ 1945.

The US Navy was well aware of the advantages such a system had, but they delayed it's thorough implementation because of different war-time priorities. Hence, only the Iowa class received a fully integrated RPC from the first stage. North Carolina and South Dakota classes were fine-tuned in these aspects in 1942-1943.
The final "product" - the integrated fire control system aboard American ships - proved to be an exceptional complement to the 3x3 guns turrets, as practice tests during and after the war proved.

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Re: KGV class

Postby dunmunro » Wed May 26, 2010 7:47 pm

The USN certainly benefited from having RPC in the MK37 system, especially when VT ammo became available.

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KGV speed and displacement

Postby alecsandros » Fri Jul 22, 2011 11:14 am

I'm having a problem with PoW's claimed performance during DS:

It's about speed.

Before the battle:
WIth PoW at ~ 41500-42000 tons, and maximum overload power, it probably could have probably exceeded 29kts for brief periods of time. However, when actualy attacking, I doubt very much that Hood and PoW could mantain the same 29kts speed while moving against the wind and on moderate sea.

The Germans considered PoW speed at 28kts during the battle, and this is also the probable correct speed at which these 2 ships could mantain against the wind.

After the battle.

The captain reported speeds of 26-27kts max after suffering hits from Bismarck. At least 400 tons of water entered the ship (if not 600), and I don't know if counterflooding was ordered ? This would have increased the tonnage by quite a bit.

The Germans reported PoW at 25kts after the battle.

The propeller shafts were turning at 230rpm and the pitometer log shows speed > 28kts throughtout 6:00 - 7:00. Again, I'm at a loss to understand how a ship which was heavily manouvreing to avoid Hood's wreckage, and then to turn away from Bismarck and escape, with 2 underwater holes, could mantain a continous > 28kts speed. Turning a ship affects the speed quite a bit.

=====

So, I don't find it plausible at all that a heavy manouvreing ship, with 400+ tons of water coming in, could mantain about the same actual speed as it had while navigating on a straight course and undamaged.

My guess is that captain's Leech report is correct, and his ship could do 26-27kts at best after the battle, with occasional speed drops while turning. I do not know why the pitometer log shows 28.4, but it is very suspect that it is almost the same speed the ship had before the battle.

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Re: KGV speed and displacement

Postby dunmunro » Fri Jul 22, 2011 7:13 pm

RN captains don't report the ships overload speed capability when giving their estimated best speeds.

Here's PoWs' track before and after the battle:

http://www.hmshood.com/history/denmarks ... Wtrack.jpg

and here's some tactical turning data from Hood:

http://www.hmshood.com/ship/hoodspecs4.htm

As long as KGV did not use full rudder, the speed loss in turns is minimal. One of the design features of the KGV class, was a fairly small rudder. This caused a large tactical turning radius, but a side effect was less loss of speed in turns.

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Re: KGV Class Battleships

Postby RF » Sun Jul 24, 2011 6:36 pm

I find the fact that the KGV class had a small rudder making turns at a loss of speed interesting, as it poses the question why. Particulary as it affects the battle readiness of the ship.

Would I be right in surmising that this factor contributed to the sinking of POW by Jap torpedo bombers?
''Give me a Ping and one Ping only'' - Sean Connery.

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Re: KGV Class Battleships

Postby dunmunro » Sun Jul 24, 2011 10:09 pm

RF wrote:I find the fact that the KGV class had a small rudder making turns at a loss of speed interesting, as it poses the question why. Particulary as it affects the battle readiness of the ship.

Would I be right in surmising that this factor contributed to the sinking of POW by Jap torpedo bombers?


The KGV class and Hood had rudders of approximately the same area.

I not quite sure what you are saying, but rudder design is always a trade off. Bismarck had twin rudders giving a much smaller tactical turning radius than KGV. Did Bismarck's twin rudders save her? A smaller, single rudder may have enabled Bismarck to steer with her props after the rudder became jammed.

PoW may have avoided some torpedoes with a smaller turning radius, but the resulting loss in speed may have allowed others to hit. Phillips decided to manoeuvre at 25 knots, but an increase to 26 or 27 knots might have caused the port side torpedo hit to miss astern. If PoW had been hit on the rudder and it became jammed, she could have steered with her engines...Its simply not possible to isolate one design factor like the rudder, since there are always pluses and minuses in each design.


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