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Naval wargames in the Great War - rangefinders
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BarrandStroud



Joined: 09 Jun 2006
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PostPosted: Fri Jun 09, 2006 5:48 pm    Post subject: Naval wargames in the Great War - rangefinders Reply with quote

Gentlemen, just discovered your site - facinating stuff. My friends and I have fought Great War naval battles fro many years. We use a unique gunnery system that attempts to focus on achieving straddles as well as scoring hits. It's very much a two stage process, that gives initial advantage to those with the best rangefinders (and best visability if appropriate) and then advantage switches to those best able to maintain the range - in effect those with the best fire control systems.

Now my question for you relates to our latest forays into the Med' and the employment of French, Italian and Austro-Hungarian warships. Have you information regarding the types and size of rangefinders used by those navies. Barr and Stroud information indicates that the French and Italians used B&S equipment - presumeably the 9 foot version - but I cannot confirm that. The A_H army certainly used B&S equipmewnt - but we have pondered the possibility of the navy using Zeiss rangefinders as (we believe) did the more modern Russain capital ships. Any thoughts?
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tone
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PostPosted: Sat Jun 10, 2006 1:30 pm    Post subject: Reply with quote

Hi, Phil -- good to hear from you.

I might be able to find some info on French equipment. Let me see if I can rouse an expert to come see your question.

One thing I note about RF is that none of them perform to the level catalogued for them in manuals or in peacetime practice, and the reasons why seem to be lighting conditions, smoke, spray and vibration.

tone
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BarrandStroud



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PostPosted: Sun Jun 11, 2006 1:47 pm    Post subject: Rangefinders Reply with quote

Thanks for your efforts Tone whatever the success -

I note your comments about conditions etc and whilst I don't totally disagree, the evidence of quite a few engagements/or parts of engagements suggests to me that in similar conditions initial gunnery performance was not constant. Now that's unlikely to have much to do with Director control etc - that comes into play as the gunnery duel continues. I'd accept that crew quality might well have been an issue, but at ranges over say 12,000 yards British gunnery was generally pretty poor, except where the 15ft B&S rangefinder was in action. Consider the 5th battle squadron and the battlecruisers in the runto the south. The conditions must have been fairly similar and yet the former achieved more hits at a longer range. Admittedly not under effective fire, but even so. As for the argument that Beatty's ships were affected by their own manouvers, this just doesn't stack up. The Dameresqe and the plotting table should have coped well with those changes. And yet British salvoes were repeatedly well over. Indeed intial salvoes two-three thousand yards over suggests a complete over estimation of the range and not just the rate of closing. And why did most of Hipper's ships get the range almost immediately. I can't believe that it was crew quality and let's face it they had first sighted each other at over 25,000 yards so it wasn't visablity. No it must have been the rangefinder effectiveness at longer ranges.

You may be interested to know that we have played a number of naval war games for this period and our house rules have produced both traditional results and give a good feel how it must have been as a gunnery officer. The rules use a one minute game turn and a seperate salvo/ hitting routines. I suspect this has led us to be rather protective about the key role of the rangefinders - but nothing else we've tried over the years (and our first games were over thirty years asgo now) has ever come close.

Sorry I don't mean to preach - i'm sure you know foir more about the topic than we do but I hope your open to be convinced by our arguments!!

Thanks agin for nay information you can get for us.

Phil
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jwduquette1



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PostPosted: Sun Jun 11, 2006 10:42 pm    Post subject: Reply with quote

Visibility issues as a function of spray obscuration on optics is rather ubiquitous in the after action reports generated following Dogger Bank. A large number of officers commented upon this problem – this was particularly true with gun telescopes. Although Range finders were also not free from visibility issues associated with spray obscuration. Moore on HMS New Zealand indicated that water accumulated on the upper decks would be sprayed upward from the muzzle blast of their own guns. The spray would douche the periscope sights and range finders. Spray from the wind direction, the ship’s speed, as well as German shorts also handicapped sighting and ranging. Various suggested solutions included: screens, improved hoods, sponges(?), and/or swabs(?), etc.

The report by a Lieutenant G.P. Bowles of A-Turret, HMS Lion, is typical of the spray related sighting challenges:

“About 8.50 I heard "B" turret ordered to stand by to fire single shots at the rear cruiser, which ship we were then trained on, I found it was extremely uncomfortable with my head through the sights hood with "B" firing, also the spray was then pouring over the turret making it extremely difficult to see the enemy, so I partially closed the top and went to my periscope in turret which was ready to fire, as I had loaded the guns directly I saw we were chasing the enemy's cruisers. I was then ordered to stand by to fire single shots. We then commenced firing by order, neither I nor the gunlayers could make out clearly the fall of shot which at first appeared to fall short, the range being 20,200 yards. Soon after this "A" and "B'" commenced firing salvos, and finally all turrets engaged the rear cruiser, who I imagined we were hitting. About this time the right gunlayer reported that he could not see anything through his periscope, so I gave orders to the left gunlayer to carry on firing. This, of course, made the fire slower from the turret. The left gun must have fired six rounds before the right gunlayer reported he could see again; but all the time he was getting a tremendous lot of water into his hood…(Later in his report) Difficulties. – Spray in the glasses very bad when steaming fast into the wind; also feel the effect of short salvos throwing up water.”

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JD
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JspencerCE



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PostPosted: Mon Jun 12, 2006 6:11 am    Post subject: At Anthony's request... Reply with quote

The French used B&S RFs from 1907 through to WWI and beyond. Most would have been 4ft to 9ft models.

In the dustruction of the Zenta, one French BB straddled on the first salvoe at maximum gun range. There had been time to gather information, to allow accurate calculations to be done. Whilst not director controlled, fire was directed from the blockhouse (had been on French warships since 1896 and maybe before), orders and details sent to a calculation room (below armour) onto FC plotting tables that have several refinements over the Dreyer system and several differences (no bearing plot, but range plot sloped up to face the user for example).

French opinion on RFs, is that they are not reliable (heat, atmosperic effects etc) and one must always spot. In the case of bad visability, the gunnery officer should deliberately shoot short and creap towards the target.

I would add that constant training (something Beatty's ships lacked) is required for excellent gunnery. A 15ft RF contains no advantages in terms of magnification over a 9ft RF and the difference in performance between the 5BS and the 1BCS cannot be put down to a wider base alone. However the 5BS was exceptioanlly well drilled. German RFs could halve the magnification of there RFs - this allows you to see a target twice as bright.

Postwar the French intorduced stereoscopic RFs into their warships. Most ships were completed with both types for a while and then just before 1940, we start to see vessels carrying only one type.
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tone
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PostPosted: Mon Jun 12, 2006 9:25 am    Post subject: Re: Rangefinders Reply with quote

BarrandStroud wrote:
As for the argument that Beatty's ships were affected by their own manouvers, this just doesn't stack up. The Dameresqe and the plotting table should have coped well with those changes. And yet British salvoes were repeatedly well over. Indeed intial salvoes two-three thousand yards over suggests a complete over estimation of the range and not just the rate of closing.


I agree that maneuvers should not throw a RN ship's range or deflection off at all for reasons we both seem to understand, even though this fallacy is often cited. Indeed, the British ships with their gyrocompass-informed dumaresqs had a completely automated capacity for this.

John Brooks, however, suggests that Beatty's heading and line of bearing in combination with the wind condition conspired to wreath his line in smoke throughout the crucial phases of the Run to the South. Such would have been a killer to any visual range-taking endeavors.

Quote:

And why did most of Hipper's ships get the range almost immediately. I can't believe that it was crew quality and let's face it they had first sighted each other at over 25,000 yards so it wasn't visablity. No it must have been the rangefinder effectiveness at longer ranges.


One wonders how many actual rangetakers contributed, however, to Beatty's gross overestimation of the range. Considering that turret rangefinders often had trouble seeing the object, it could actually have been just a single operator at a single instrument -- the Argo instrument in the armored gunnery control tower. Even if doctrine supported it, the gaffe of firing before the flagship who is obviously nearer in range implies that no ship would want to open fire before Lion, even if they had better ranges indicating that they were already within reach.

Quote:

You may be interested to know that we have played a number of naval war games for this period and our house rules have produced both traditional results and give a good feel how it must have been as a gunnery officer. The rules use a one minute game turn and a seperate salvo/ hitting routines. I suspect this has led us to be rather protective about the key role of the rangefinders - but nothing else we've tried over the years (and our first games were over thirty years asgo now) has ever come close.


I have been studying this for several years now in great detail, and have to suggest that it would be easy indeed to overemphasize the role that rangetaking has after fire is opened, when spotting becomes the litmus test of finding deflection, and then range and then the rate.

A primary characteristic of RN (or, for that matter, any service's) gunnery in this period is that spotting, rangetaking, and statistical inferences of enemy course and speed achieved through plotting are not simply inputs to a black box that spit out a range and deflection. That is, they ARE inputs, but they may provide contradictory information and the choice made as to which to grant credibility is an important element and one which might well not consider each information source with equal value.

After all, if you were the gunnery officer and someone with binoculars tells you your shells, when they can be seen at all, appear to be straddling the target, and your plotting staff, while admitting that few ranges are being taken at all indicates that the gun range in use appears suspiciously high relative to the plotted range, you are not apt to trust the visual range estimates in preference to spotting. Spotting is simply the more forensically proximate indicator to what is actually going on.


Quote:

Sorry I don't mean to preach - i'm sure you know far more about the topic than we do but I hope your open to be convinced by our arguments!!


No one convinces me, alas. :) But I don't mean to say I'm obstinant here. I maintain a loose "feel" for how these things work. If I can throw a possibility back at you, it would be that you might have convolved spotting and rangetaking a little here and still come up with a good model. My own sense is that rangetaking played its greatest role in the RN during the opening phases of the battle and almost lost its sway once shellfall was being observed, for the twin reasons that the act of firing further militated against being able to take ranges at all and because the spotting was simply the more trustworthy observation.

One possibility to consider here is obtaining a copy of the newly reprinted Jutland Despatches. While they are less rigorous than they might be, an effort was made to ask each ship to submit its range plot and that few delivered on this request. Sadly, the reasons for the failure are not always spelled out, but the reason cited by enough ships to create a strong impression is the unthinkable: no usable range plot was maintained.

One would think that this really takes the wind out of the Argo vs Dreyer debate, but while it has been insufficient somehow to accomplish this, I feel it should at least indicate that conditions of visibility due to some confluence of factors rendered range taking nearly impossible for the RN.

tone


Last edited by tone on Mon Jun 12, 2006 9:35 am; edited 1 time in total
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PostPosted: Mon Jun 12, 2006 9:31 am    Post subject: Reply with quote

jwduquette1 wrote:

The report by a Lieutenant G.P. Bowles of A-Turret, HMS Lion, is typical of the spray related sighting challenges:

“About 8.50 I heard "B" turret ordered to stand by to fire single shots at the rear cruiser, which ship we were then trained on, I found it was extremely uncomfortable with my head through the sights hood with "B" firing, also the spray was then pouring over the turret making it extremely difficult to see the enemy, so I partially closed the top and went to my periscope in turret which was ready to fire, as I had loaded the guns directly I saw we were chasing the enemy's cruisers. I was then ordered to stand by to fire single shots. We then commenced firing by order, neither I nor the gunlayers could make out clearly the fall of shot which at first appeared to fall short, the range being 20,200 yards. Soon after this "A" and "B'" commenced firing salvos, and finally all turrets engaged the rear cruiser, who I imagined we were hitting. About this time the right gunlayer reported that he could not see anything through his periscope, so I gave orders to the left gunlayer to carry on firing. This, of course, made the fire slower from the turret. The left gun must have fired six rounds before the right gunlayer reported he could see again; but all the time he was getting a tremendous lot of water into his hood…(Later in his report) Difficulties. – Spray in the glasses very bad when steaming fast into the wind; also feel the effect of short salvos throwing up water.”


I am always bollixed by how many sources there are, and so I get confused, but I though I should point out the surprising fact in the above that the Lieutenant seems to indicate that Lion was firing on the gong in local firing, and not in director firing. Were she in director fire at this stage, the gun layers would be following the pointer and (at best) using their periscopes to satisfy their curiosity of how the action was going. They would certainly not be triggering the guns.

tone
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jwduquette1



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PostPosted: Mon Jun 12, 2006 5:41 pm    Post subject: Reply with quote

There is a comment from another gunnery officer regarding the initial shoots from Lion at Blucher. Apparently Turret-B opened the engagement because Turret-A was constantly awash in spray – or something to that effect. I’ll try to hunt down the exact wording and post it.

As to indirect lay – I don’t know – I’ll bow to your superior understanding of gunnery techniques of that period. I assumed the comment regarding the right gun layer not being able to see through his telescope and thus the right gun wasn’t firing was significant. My gunnery experience is with tanks. Obviously mostly direct fire training, but we did sit through lectures on indirect lay. These sorts of shoots would be done with a gunner’s quadrant and azimuth indicator – with appropriate adjustments to elevation and deflection for spin drift, angle of site, non-rigidity effects, wind, etc., etc. Of course we were not moving, nor were we pitching and rolling, although we did have to account for cant. But we didn’t need to see the target to conduct the shoot. We just needed an observer who could see the target, and who could direct our fire onto the target. Add, drop, left, right so many meters to keep our spotting rounds along the observer target line -- till we brakected the target -- than a platoon or company sized fire for effect. I suppose the ground combat version of spray obscuration would be analogous to a fellow randomly pitching mud onto the forward observers binoculars every 20 or 30-seconds. The observer than needed to clean off the binos and make his fall of shot sensing before the next blob of mud got chucked into his face.

However, the comments about spray being a problem with spotting and ranging is fairly rife throughout the various RN after-action-reports generated right after Dogger Bank. I assume that since British were chasing the German sterns that the German RFs and sundry optics would have been better shielded from the effects of wind driven spray. Conversely, I suppose their own funnel smoke should have been an issue for ranging and sensing fall of shot.
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hn



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PostPosted: Mon Jun 12, 2006 6:12 pm    Post subject: Reply with quote

Have been following this current thread with a deal of interest. I agree with the comments made. There is one or two things that occur to me, that may be relevant or not. Am I am correct in remembering that Chatfield wanted to open fire before they actually did but Beatty wasn't available at the time to make the decision. I also wonder if there was a problem in information handling, re ranges and plots on individual ships during The Run to the South. Although it does seem improbable that all the BCF had a similar problem. It would be interesting to know how much practice they had been getting with the equipment. I know the BCF was short of gunnery practice, but I wonder how much the crews in the TS, range taking stations and spotting stations had been working through their procedures, or, when it all started to happen for real they were refreshing memories on the job and there followed a degree of improvisation. I don't know I may way off the mark, but I do know that even with the regular "Thursday war" procedures don't always run how they should and sometimes once errors creep in they can accumalate. I suppose what I'm saying is there could have been a combination of human and technical errors that combined with the prevalant situation to cause the gunnery problems.
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JspencerCE



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PostPosted: Tue Jun 13, 2006 1:09 am    Post subject: Correction.. Reply with quote

Actually, having checked, the French Dreadnoughts all entered service with 15ft B&S RFs, although they were supposed to recieve 9ft initailly.

The Bretagnes had a triplex arrangement (3 RFs, one on top of the other), in order to provide a few readings from which an average could be taken.
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PostPosted: Tue Jun 13, 2006 11:14 am    Post subject: Reply with quote

jwduquette1 wrote:

As to indirect lay – I don’t know – I’ll bow to your superior understanding of gunnery techniques of that period. I assumed the comment regarding the right gun layer not being able to see through his telescope and thus the right gun wasn’t firing was significant.


The point is surprising (to me), but crystal. In director firing mode, the elevation and training angle for the guns is determined at the director, and the entire scope of duty for the gunlayers and trainers (actually, turret director trainers) at the guns became one of simply orienting their guns until they matched the angles on special receiver instruments showing what the director wanted. The guns would fire when the director layer pressed the trigger. The layers in the gun mount would watch a receiver and handle only the hydraulic valve to elevate the gun to satisfy the receiver. They'd have no time to look at their periscope except perhaps when the gun was being reloaded, and at this time, the depression of the gun for reloading would have had them seeing only water anyhow. The trainer, on the other hand, would have little to do (the training is done by that turret director trainer below in director fire) and would probably be providing a play-by-play to others in the turret.

In local fire, the gun layers would do just as described in your quote: they would have looked through their periscope, and pulled a trigger to fire the gun when the crosshairs next approached the aim point after hearing a firing gong chime. I am not wholly sure how one layer could fire the other gun accurately. I would have to guess that he'd read off what his elevation receiver indicated was his elevation angle, and have the right layer apply the same angle to that gun, and that the trigger wiring allowed cross-firing. That last bit I am really uncomfortable with, as I have seen wiring diagrams for this, and have not perceived that this was part of the design (but I am not great shakes at reading wiring schematics).

tone
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BarrandStroud



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PostPosted: Wed Jun 14, 2006 7:49 am    Post subject: Reply with quote

Gentlemen, thank you all for your comments/evidence/information - especially that regarding the triple 15ft rangefinders for the French. Presumeable they played a role in the demise of the Zenta.

I didn't mean to underate the importance of spotting after the initial salvoes - apologiesif I gave that impression - but I wonder if spotting splashes is somewhat easier if your relatively near the target to begin with? All the excellent material on the site about the deflection calculations etc seems to imply that a better input quality for range speed and course is essential to getting a good estimate. After all you would presumeable be looking at the target waiting for the splashes?

I guess overall I am convinced enough to give a bit more thought to the effect of spray - does anyone have any evidence of ships being manouvered in battle to minimise this effect. We know that commanders tried to get the best of the light but I've never heard of one trying to minimise spray effects. Admittedly the requirements of the engagement may often have prevented it, but surely not always? For example I don't recall von Spee fleeing in a particular direction to interfere with Sturdee's gunnery and one would imagine conditions were quite good for this be effective?

Again, thanks for all your help etc - and should you come across any further data on Austrians or Russains.......

P.S. if any of you would like a copy of our rules for this period please feel free to drop me a personal e-mail (philutzow@aol.com)
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PostPosted: Wed Jun 14, 2006 9:40 am    Post subject: Reply with quote

BarrandStroud wrote:

I didn't mean to underate the importance of spotting after the initial salvoes - apologiesif I gave that impression - but I wonder if spotting splashes is somewhat easier if your relatively near the target to begin with? All the excellent material on the site about the deflection calculations etc seems to imply that a better input quality for range speed and course is essential to getting a good estimate. After all you would presumeable be looking at the target waiting for the splashes?


For myself, I only mean to share my own uncertainty as to how the various systems of fire control actually wound up using the data they were designed to use. Certainly, you have no call to apologize at all.

Argo and Dreyer systems were conceived on the assumption that ranges and bearings would be fairly easy to obtain and could form a basis for a continuous depiction of enemy speed and heading, and that by subtracting out the motion of own ship, a relative motion could be arrived at reliably and, it bears repeating, continuously. This knowledge should allow the firing ship to regularly straddle the target and obtain hits at reasonably high frequency. If all worked as simply as this, spotting, one would guess, would be helpful merely as a sanity check and to provide an early means of detecting a change in enemy speed and heading before such alteration would manifest itself in plotted form.

However, I think in few test of battle did this prove the norm. Ranges were grossly erratic when they were obtained, and failed in any manner to conform to the modest errors forecast in their manuals. The reasons seem varied, and each ship tells a slightly different story, but when accounts repeatedly state that the ship being fired at blew up and sank when we know no such event occurred, one must wonder how reliable the much finer visual test of determining are the halves of the image of the object bifurcated or in coincidence could be considered.

While I have not studied it in detail, I am told that one of the post WW-I concepts chosen in creating the Admiralty Fire Control Table was to place greater emphasis on visual estimation of target inclination and less on plotted observations.

tone
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PostPosted: Wed Jun 14, 2006 11:41 am    Post subject: Reply with quote

tone wrote:

In local fire, the gun layers would do just as described in your quote: they would have looked through their periscope, and pulled a trigger to fire the gun when the crosshairs next approached the aim point after hearing a firing gong chime. I am not wholly sure how one layer could fire the other gun accurately. I would have to guess that he'd read off what his elevation receiver indicated was his elevation angle, and have the right layer apply the same angle to that gun, and that the trigger wiring allowed cross-firing. That last bit I am really uncomfortable with, as I have seen wiring diagrams for this, and have not perceived that this was part of the design (but I am not great shakes at reading wiring schematics).


I think I should retract this rambling bit. There is nothing in the above to indicate that the left layer was firing the right gun. I think what they are implying is that the right gun fell altogether idle for a period.


tone
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jwduquette1



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PostPosted: Wed Jun 14, 2006 7:19 pm    Post subject: Reply with quote

BarrandStroud wrote:
P.S. if any of you would like a copy of our rules for this period please feel free to drop me a personal e-mail (philutzow@aol.com)


I have been an avid wargamer for as long as I can remember. I would be interested in reading a copy of your rules. I will forward along an email.

Thanks
Jeff
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