"1895-1918 Naval Gun Ranges" Topic

Does anyone have a reference source, or the data for naval guns ability to "hit" targets in the 1895-1918 period?

By "hit" I mean, not what was the maximum range of a weapon, but what was the range that a ship commander had a decent change of hitting a target at.

At the Falklands in 1915 it appears that both sides could hit at 14,000 yards and under in clear conditions, but that the British BCs could not hit at 16,000.

By Jutland it appears that ranges had increased somewhat to the 16-18,000 range.

In the pre-dreadnought period (say before 1907) I've read that 10,000 yards was the maximum that a ship's gun was expected to be able to hit a target with some chance of doing so. Did not the Japanese destroy the Russians in 1905 at ranges under 7,000 yards?

Your thoughts and data. Thanks.

Dan

Well.. so many variables.

In the pre-dread period, there were no rangefinders, guns were trained by eye and hand, and spotting was limited to the distance at which a human eye could distinguish a shell splash. I'd expect the range to be 7,000 – 10,000 yards, yes.

I am not sure that the BC's at Falklands had (then) modern range finders. They were a relatively new thing in 1912 and not all ships started the war with them. That may explain the fall-off after 14,000 yards. There may have been some threshold of ballistic performance between 14,000 and 16,000 yards too.

Good questions.

Dan,

That is a particularly tough question to answer given the breadth. I don't know that I can provide any hard answers but at least I can give you some food for thought.

The ability of a gun to hit its target (assuming it is in range, of course) is, excluding all the environmental (visibility, sea state, etc.) and tactical considerations (speed, maneuvers, range, etc.), more a factor of the fire control being employed than anything else. Over the course of the 1895 to 1918 period fire control systems ranged from A) Basic gun-sights, no fire control instruments, no director control and manual stabilization to Z) Telescopic gun-sights, mechanical computer, optical range-finders, director control system and gyro-assisted stabilization. So, the better your FC system, the better chance you have of getting a hit (all else being equal).

Of course, once you get below circa 5000 yards, the need for precision becomes somewhat less important due to the flat trajectory and short time-of-flight. Rear Admiral Sotokichi Uriu, IJN in his Special Instructions to the Fourth Division, 1904, had this to say: "At ranges of more than 4,500 meters (4,900 yards) all the adjustments of the sights are to be very carefully made, but at less than 4,500 meters it will be better if adjustments for the enemy's speed are neglected, and the bow aimed at."

Like Vsb said, so many variables…

Too many variables to give you any accurate information with any specificity as stated above. Perhaps you could refine your question a bit? Might help with at least some better attempts to answer it?

I read somewhere that durng wwII at anything beyond short range within visual sighting range resulted in around 5% hits. The US suffered a lot in the south Pacific because at night they dipped will below this while the Japanese did not.

At Jutland,

The British: 4598 heavy (9.4" and above) shells were fired, there were 100 hits total, or 2.17%

The Germans: 3597 heavy shells were fired, with 120 hits, or a strike rate of 3.33%

Many or even most ships had directors by this time.

I find that it is too easy to find maximum gun ranges for the period, but hardly any information on FC ranges.

Gamers being gamers, they want to use the maximum ranges. I, being I, want to have a reasonable FC range.

Knowing that a British 13.5" 45 gun can fire 23,000 yards in 1910 is fine, but what is the practical range that a ship equipped with such a weapon would open fire.

I've got a gut feeling (just a guess) that prior to the introduction of modern FC equipment in the 1912/1914 period that about 10,000 yards was that maximum, with the range going up a thousand or so yards a year after that. War practice and experience also increased the range.

One notes in most war histories that commanders tried to close range for their weapons to bear at ranges that were less than their maximum weapon ranges. One assumes then that the weapons could fire much farther than spotting could be observed and corrected.

Dan

Same goes for torpedo firing as the weapons seemed to have had several times the maximum range that they were usually fired from (10,000 yards maximum, but destroyers trying to close to 3,000 to 5,000 yards to fire).

Dan

One of the biggest problems is that at long and extreme range it is impossible to spot off your own shell splashes, as the image is so small that they become indistinguishable.

That was one of the main complaints about the last of the pre-dreads- those with mixed calibre big guns. On a Danton class pre-dred for example the 9.4's splashes could not be distinguished from a 12" at anything but short range.

Pre WW 1, 10,000 yards id very long range. Pre Percy Scott, ranges were even shorter. Look at accuracy in the Spanish-American War, The Sino-Japanese War, and the Russo-Japanese War. I'm pretty sure that people were surprised by the long engagement ranges in the RJW…

-Kle.

I've been doing a little research on this sort of thing for one of my own design projects.

Gunnery took place at much, much less than the theoretical maximum range for the guns. Doctrine, or what there was of it anyway, and lack of good fire control kept gunners from opening up at "wargamer" range.

Most of the gunnery action between Lissa (1866) and the Spanish-American War (1898) took place at 4000 yards or less. I'd venture to even say that most of it took place at less than 3000 yards.

By the Russo-Japanese War in 1904-1905 accuracy at range had increased to allow engagements out to about 8000 yards. My primary period of interest for my current project stops there, so I can't say about ranges after 1905. The 16,000 yard range sounds about right for WWI.

In the game design I'm working on now, allowable gun range is restricted to the actual engagement range for the period. It has an interesting effect on scale, so that Tsushima f'rinstance can actually be done on a large tabletop with 1/6000 scale miniatures, using the same surface scale as the miniature scale. I think Span-Am War and Sino-Japanese War could be done in scale on a large tabletop using 1/3000 scale ships, but all my ships for those periods are 1/1000 scale. Oh well.

So, a reasonable guess would be that actual ranges would be:

1895-1900 under 4,000 yards (maybe under 3,000)

1900-1910 under 8,000 yards

1910-1915 under 12,000 yards (maybe under 14,000)

1915-1920 under 16,000 yards

Dan

Yeah, something like that.

I think they opened fire at 20K during Jutland, but I don't think it was what you'd call effective range.
-Kle.

At Jutland, the battlecruisers opened fire on each other at near 18,000 yards. Within six minutes the range fell to 13,000 and several hits were scored by each side during that interval – Moltke and Princess Royal being each heavily hit.

Dear All,

I know it's not much help right now, but back in 1977 our rules "Cordite And Steel" provided the exact information for all naval guns from around 1890 to 1920 (and ultimately to 1945). Mind, only the smallest selection of this data was actually in the one edition of the game as we expected to produce supplements that would complete the collection, but with TSR this never happened.

It took two years of sneaking main frame computer time back in the mid 70's to complete the computer program, but using books on exterior ballistics printed before 1920, we were able to compute the maximum range of any gun, and the consequent danger spaces for all targets in 5' increments, from 5' to 50' above the water.

The one factor virtually all naval wargames rules writers ignore is the importance of "danger space" as the measure of a gun's potential to hit a given target at a given range.
Danger Space is that area behind a target into which if a shell were to fall, it would in fact strike the target first. As a shadow falls behind an object, and a rock would be thrown to land in that shadow, it would strike the object instead.

This danger space varies with the height of the shell above the water, the angle at which it is falling (and only very low angles before the late 1920's and later), and the height and width of the target. And this is exactly what the computer program developed by my late colleague, Eric Just, could do, among other things.

Where Danger Space info was provided in sources such as "Janes" and "Brassey's" for the years of interest to us, we found our figures were always within a few percentage points--when not identical--to those calculated at the turn of the 20th Century.

Further, we were able to calculate full penetration values in 1/2" increments at all ranges against a calculated standard of armor effectiveness based on Krupp Cemented.

Factors required by the program included muzzle velocity, shell weight, and form coefficient (shell shape). Factors were "zeroed out" included barometric pressure and humidity.

The ship cards for each class indicated armor thickness on the same scale for relative effectiveness. For example, if a vessel was built with 10" of iron as armor on a given section, it's calculated equivalent protection was 5" of Krupp Cemented.

We still have around 40 pounds of fanfold computer printout with all this data on hand, as well as our own original reference forms to which we transcribed all the relevant data.

Best of all, however, is that some thirty years later, we are revisiting the rules and the computer program and are actively trying to bring the game back, but this time with some improvements to game mechanics and rules, and ALL the gun data tables at once. "Cordite And Steel II" should be ready for release by the end of the year, and the data will end all the searching and guesstimating gamers have been doing for decades.

And perhaps the most significant additional information we will now be able to provide are the statistical percentage chances to hit with each gun at all points along its range against targets of all height. Thus the game can still be played in miniature on floors or table tops, in scale with the models of choice, using player range estimation, or by using percentile dice, whichever is preferred.

The presence of centralized Fire Control, as opposed to the essentially pre-Dreadnought practice of fire control by individual gun crews, is crucial to determining at what ranges actions could be opened, no matter what the physical range of a gun might have been. This can also be reflected in the use of the base percentages to hit, as well as crew training, experience, physical condition, and more.

To Dan Cyr, if you have a specific gun in mind, you are welcome to send its specifics (size, caliber, mark number, nationality, etc) and I can summarize it's capabilities for you.

TVAG, thanks for the offer. At this point I'm just trying to narrow down the "effective" range of all weapons, not a particular few. Knowing that a German armored cruiser in 1914 equipped with 8.2" and 5.9" guns, both of which have different maximum ranges, but that would only be fire at a maximum range of 12k yards, that is what I want to know. Perhaps a British 12" gun could fire 20,000+ yards, but if the maximum "effective" range is 12,000 yards, then I can restrict firing beyond that range.

As suggested earlier in a post, 2-3 percentage hits makes firing at long ranges silly as the ship would run out of ammo before damaging (enough) or sinking an enemy ship.

Dan

<p>"As suggested earlier in a post, 2-3 percentage hits makes firing at long ranges silly as the ship would run out of ammo before damaging (enough) or sinking an enemy ship."</p>

I dunno…. figure most BB's carried around 80-100 rounds per gun, that could be 20-30 hits for a 10-gun BB. That was enough to put Lutzow down, and most BB's and BC's that were sunk by gunfire went down with fewer hits.

Now… silly is firing at a speeding weaving destroyer at 39,000 yards, radar or not.

I agree with you about the hits on Lutzow, but then most of the hits were at much shorter ranges than maximum weapon ranges, right?

Lots (most) of the firing was at 14-16,000 yards, not the 22-26,000 yards the weapons could fire if desired.

Dan

And, not to flog a dead horse, but would Lutzow have survived if not forced to sail as hard as she did, what with the "death charge" and then the escape?

The German ships seemed to die by inches, not in one blow as did the British BCs.

Impressive ship building, plus the problem the British had with bad shell design and manufacturing.

Dan

to The Virtual Armchair General,

I have Cordite and Steel that I picked up back in 1979.

Is there a way to get your other gun tables for 1890-1918 that are not in your rule book?

Here's how I see it based on my readings:
First, it's a matter of range finding and building up a course and speed plot to get an idea of where the target ship will be in 15-60 seconds (basically the rounds time of flight). That can take up to 10 minutes depending on visibility, rangefinder type, and course plotting method (if any).

Then fire some spotting rounds to get consecutive under and over shots. Ladder method is best and quickest. That can take another 3-5 minutes.

Ideally, by now you have determined the target range to within 5% to 10%. A target at 12,000 yards would be estimated at 11,000 to 13,000 yards or +/- 1000 yards. Spotters and rangefinders send readings to the central control/plotting room to track the target and speed/course changes and salvo results. Poor environmental conditions can degrade this to a great degree.

Next start firing half salvos in an attempt to straddle the target. If the salvo sheath is too long you have a better chance of a straddle but it would be too spread out to get a hit. A salvo sheath that is too short will have a lesser chance of a straddle but could achieve multiple hits if it does straddle.

If you estimate the target to be in a +/- 1000 yard area (2000 yards) then a 400-yard salo has approximately a 20% chance to straddle, a 500 yard one a 25% chance. A battleship with a 30-yard beam and a 20 yards danger space takes up an area of 50 yards. A 4 round salvo of 400 yards length that straddles should deliver about a 50% chance for 1 hit and 0% chance for 2+ hits.

Once you straddle shorten your salvo sheath (if your fire control allows it) to achieve more hits. The target can maneuver to get out from under the salvos but will most likely not be able to keep his guns on the target. To counter this ships often went to rapid fire once they achieved a salvo.

I have not played the popular naval games much but they seem to overly complicate the process.

At longer ranges, the angle of descent is about 1.5x the elevation angle.

My translation is you don't have a % chance to hit with each gun except at short distances. At long distances, you can only attempt to straddle the target.

Seas of War has a good simulation of the gunnery procedures and accuracy factors. I have Cordite & Steel which is good too.

I made my own tables and have a different plotting method using an AOD method to determine a hit on the superstructure, deck, verticle armor or waterline/underwater without die rolling.

Links:
link

We had a detailed discussion on this stuff a few years ago: TMP link

Wolfhag

One limiting factor is gun elevations. These late 19th Century guns and early 20th century guns often had about a 15° maximum. So whatever range you could get with that would be a hard limit.

Thanks Guys….will look them over…..

Hi Brigman2000 –
What is the goal of your project? I ask because naval gunnery during the period in question (1890-1918) went through quite dramatic changes on multiple fronts. Gun data alone will not provide the answer.

B

looking for penetrations for guns 1890-1902 for ranges out to 9000 yards and/or with the falling angles of shot at ranges over 5000 yards. This is to be able to calculate penetration of flat deck and sloped deck armours out to 9000 yards or greater.

To use with Later Pre-dreadnought rules.

Sloped deck armours?

Part of the pre-Dreadnought range limitation was the fact that before rangefinders every gun captain did his own aiming and firing. Not just the controversial "mixed calibre" problem, but each main turret was firing on its own and each of the several smaller guns was doing the same. This meant as many as ten different shell splashes to distinguish from your own single gun. This meant that prior to 1900 effective battle range was really about 2000 yards or less.

Another thing I don't see mentioned often is loadout. The armour-piercing shell was a new thing and not readily trusted. During the early pre-Dreadnought era the usual shell loadout for heavy guns was 20% armour-piercing, 40% lyddite (or HE) and 40% solid shot!

Brigman2000 wrote –
"looking for penetrations for guns 1890-1902 for ranges out to 9000 yards and/or with the falling angles of shot at ranges over 5000 yards. This is to be able to calculate penetration of flat deck and sloped deck armours out to 9000 yards or greater. To use with Later Pre-dreadnought rules."

- – -

Hmmm ….. very tall order, as the period 1890-1902 was note of profound advancement in both armor and projectile technology.

On the armor front: between 1890 and 1902 the following type of vertical armor were developed: compound, nickel steel, Harvey and successively improved version of Krupp. All of these plates differed in their relative resistance.

On the AP projectile front: between 1890 and 1902, AP projectile design advanced from cast iron to cast steel and then to forged steel. Add to that the addition of piercing caps after the arrival of face-hardened (cemented) plates.
Some AP projectiles were solid shot, some black powder filled and latterly HE (melinite/lyddite/etc) filled. Also, delay-action fuzes suitable for attack of heavy armor did not exist. No HE-filled projectile (AP, Common or HE) had any hope of reaching the vitals of an armored warship; only a solid shot AP would have been able to do so.

Each combination of armor plate and attacking projectile (and striking angle in many cases) would give different piercing performance and damage effect – some fairly dramatic. In short, we are dealing with a really complicated issue – probably not what you want to be reading here.

Finally, in the period 1890-1902, the typical "effective" battle range would have been </= 2000 yards. Guns were being fired over open iron sight with absolutely no centralized fire prediction or control of any kind. 6,000 yards was considered <<<extreme range>>> in 1904.

If you are agreeable to provide your email address and I'd be happy to send (MSWord doc) notes I took from a USN manual ("Gunnery Instructions, U S Navy, 1905") that discussed the results of extensive fleet gunnery tests and trials undertaken by the US fleet in 1904. Lots of interesting data.

Some closing thoughts -
> Some ways to simplify things do exist. It is possible to crudely enumerate the relative resistance offered by the various types of armor, for example. But that will not address the failure velocities of cast iron and cast steel projectile against the more modern armors.

> Try contacting th SeeKrieg guys (Jack Joyner and Rich Sartore). They have done a mountain of research or naval ordnance for their game and IIRC they go back as far as 1895. Might be worth a "shot".

B

Sailor Steve is spot on re heavy caliber AP projectiles in the late-19thC. They were provided in limited quantities (<20% of shell outfit)and were intended to deliver 'coup de grace' blows at point-blank ranges upon otherwise crippled opponents.

B

Which guns are we looking for?

Thanks, Guys

To Blutarski,

I should have written 1890-1909 instead of to just 1902 as I wanted to cover max ranges out to the Russo-Japanese and Great White fleet periods with the ranges that's where the 9000-yard ranges come from.

Would you have the differences or thoughts regarding those ranges from the 1904 to 1909 period?

Hi Brigman2000 -
Here is some material on spotting from the USN circa 1905 -

Results of Spotting at Experimental Firing Tests

The following brief summary of experimental firing shows the results of spotting at the longer ranges. The purely spotting tests, where the fall of shots varied widely, were discontinued at 3,500 yards, though spotting was carried out up to 6,000 yards during strings which were fired to test the accuracy of the gun.

(1) At 2,000 yards.- Mean average errors of officers, 35 yards; mean of the maximum errors made by each individual officer, 78 yards; men, 90 yards. At this range there was a pronounced tendency on the part of the officers to overestimate the error of the shot. The men, on the contrary, underestimated the error. The largest error made by any officer on the Board on this test was 100 yards. The half-danger space of a 20-foot target (2,400 foot-seconds, 6-inch gun) is 138 yards. During this test shots were fired so as to fall at various points between 350 yards short to 300 yards over. Spotting may therefore be said to be very accurate at 2,000 yards, both in estimating errors and in calling hits, since, with but two exceptions, all 15 observers accurately spotted the two hits which were made at this range, though the enlisted men were inexperienced and had glasses of low power.

(2) At 3,000 yards.- Mean average errors of officers at spotting test, 55 yards; men, 82 yards. Mean of maximum errors made by each individual officer, 144 yards; men, 185 yards. Maximum error made by any officer, 200 yards. Hits on the target were correctly spotted by nearly every observer. The half-danger space at 3,000 yards is 76 yards for a 6-inch, 2,400 foot-seconds gun. Therefore the average mean error is less than the half-danger space of a 20-fot target. The shot , therefore, be brought on the target on the second shot at this range. The shells are followed at this range with ease, and after a little practice it would seem that the error might be sensibly decreased over that shown above , which was the first experience at 3,000 yards.

(3) At 3,500 yards.- Average error of officers, 88 yards; men, 75 yards. Maximum error, 350 yards. This observation was made with a long glass and smoke interfered. This shows that at this range the errors begin to increase rapidly. Following the shell through its entire flight at this range, especially with low-power glasses, becomes difficult. The half-danger space at this range is 60 yards. This range may therefore assumed to be the limit for accuracy in spotting the 6-inch gun of this velocity. This, however, be no means indicates that spotting can not be successfully done beyond 3,500 yards, but simply that here the average error exceeds half the danger space of a 20-foot target. Spotting is considered of the very greatest value at all ranges, since even at long ranges spotters can always tell whether the shot hits sufficiently far away to justify an alteration in the sight-bar. When shots fell near the target there was rarely any large error in estimating its fall. Large errors in estimating were made only when the shot fell a long way from the target.

(4) At 4,000 yards.- The accuracy test was started with the establishment of a fork, which afforded excellent experience in spotting at this range. The observations showed the average error of officers to be 24 yards; men 44 yards. Maximum error, 100 yards (though shots went 200 yards over and 200 yards short). The results would not have been so accurate had the dispersion been greater. This is practically the last range at which the 6-inch projectile can be followed throughout its entire flight. As the half-danger space for the 6-inch, 2,400 foot-seconds gun is only 46 yards at this range, it may be considered the practical fighting limit of the 6-inch gun, and hence the spotting of a 6-inch beyond this is not of much value. That is, a large percentage of hits could not be expected. If, however, day-tracers prove of practical value, thus enabling the spotter to follow the projectile to a much greater distance and thereby identify its splash, considerable success may be achieved at longer ranges. It should be remembered that the above firing was done under the most favorable possible weather conditions, with the ship at anchor and the target stationary.

(5) At 5,000 yards.- It is impossible always to follow shot throughout flight. A marked tendency was shown to underestimate errors.

(6) At 6,000 yards.- Same as above. Even the 13-inch at this range could not be followed through its entire flight. In the five shots fired, the errors were spotted with a high degree of accuracy from the splash on the water. The number of shots fired at this range was too small to make it at all conclusive. Spotting must, however, be recognized as of very great value even at this long range in the case of guns of large caliber.

Summary.- In general, 6-inch spotting may be considered sufficiently accurate to bring shots on a target up to 3,500 yards, and 13-inch can be spotted by the splash with a considerable degree of accuracy up to 6,000 yards. At short ranges there is a tendency to overestimate errors; at long ranges to underestimate them.

Smoke and hot gases are prohibitive to spotting. When a low position is chosen it must be to windward of the gun. If the day is calm it must be well away from the firing gun, especially if at long ranges, for the smoke and gases will spread out slowly and shut out the projectile before it reaches its target. No general rule can be laid down about smoke. The firing experiments were carried out in calm weather or with a light breeze blowing from the direction of the target, and almost the only location where smoke at no time interfered was the upper top, or above it. When smoke rose to the lower top it did not reach upper top in time to shut out projectile. The shock and vibration in the tops was not objectionable.

Spotting shells during flight quickly reveals any peculiarities of flight, such as wobbling, tumbling, etc.

Importance of observing the shell in flight.- Owing to the fact that most officers have only spotted at target practice ranges, they have grown accustomed to depend too much on the shape of the trajectory. When ranges are changing, the trajectory will change so greatly as to be entirely misleading. Therefore, the only way to spot is to watch the shell and see where it goes, and pay no attention to the shape of the trajectory. Even the increase from 1,600 to 2,000 yards range greatly changes the shape of the trajectory. If the shell itself is actually watched to the very end of its flight its fall can be closely estimated.

For spotting at variable ranges a table of danger-spaces and vertical projections of the water in front of the target are a great aid, and every fire-control officer should be so provided.

Shock.- No definite rule can be laid down about the shock. It seems to go in waves and is sometimes experienced at the most unexpected places. Its effects seem to almost disappear when all guns are firing together.

Observation of shell by gun-pointers.- Only in exceptional cases can gun-pointers see their own shell in flight. The shock knocks them off, and even if the wind does blow smoke aside they can not tell their projectile from any other. With one gun firing and a long range and a stiff breeze, this is different. The gun-pointer can usually see the splash of his projectile, however. This is principally a question of smoke, gases, wind, and time of flight. When all guns are firing he can not distinguish his shell, hence his observations are of little or no value. With one gun firing (an officer for pointer), and a light breeze blowing from the direction of the target, the latter could not be seen for two or three seconds after discharge.

Spotting with range-finder.- The Barr & Stroud range-finder could not measure the distance of the splash, but when using it as a glass very fair estimates could be made as to the fall of the shot. Shot could not be followed with it with certainty.

Observations of splash alone.- Although estimates can be made as to the amount of error, by observation of the splash alone, such estimates are very liable to be wild. Following the shot in all cases materially increases the accuracy of the estimated error.

Spotting wide shot.- The error in range of shots which fall very wide of the target laterally are very difficult to estimate; such estimates were frequently very much in error.

Tendency to underestimate errors at long range.- At long ranges the tendency is to underestimate errors. Large errors are almost always underestimated. Those shown in the summary of observations as being overestimated are usually small, e.g., 75 yards instead of 50 yards, while the errors of shots which are underestimated are frequently large, such as 50 yards for a 300 yard error.

Best spotting location.- Unless there is a strong wind, the bridge deck would be too low for general spotting, owing to smoke; also for the range-finder. The upper top is recommended as the best place for fire-control.

Conditions governing tests.- Concerning all the above tests of spotting. It should be borne in mind that the conditions were such as to give the maximum results possible, though the same observers with more practice would doubtless do better under equally favorable conditions. These conditions afforded the following distinct advantages:

1. Ship and target both stationary.
2. Ample time allowed for observing the splash alongside the stationary target
3. Smooth sea – no swell and no waves.
4. Perfect weather as regards light, etc.
While opportunity was not afforded on this occasion for experiments under conditions less favorable than the above, it is nevertheless realized that the difficulties of spotting would be increased with any unfavorable change in the above conditions, particularly with target and ship changing their relative bearing and distance continuously, and with considerable rapidity, and with the necessity of observing rapidly. To what extent these disadvantages would decrease the effectiveness of spotting can be learned by actual trials only. Therefore the inferences drawn from the result of spotting in this experiment should be regarded as of definite value, but rather as a probably correct indication of the nature of the results to be expected from future experiments carried out in a manner more nearly approaching the normal conditions of battle practices.

- – -

Conclusions of board of officers conducting experimental firing.- The following were the conclusions of a board of officers which conducted experimental firing in 1904:

Limit of efficient spotting.- With a 6-inch gun of 2,400 foot-seconds initial velocity, spotting can be done, under favorable conditions, with a high degree of accuracy, up to 3,500 yards, and with a less degree of accuracy it is practicable and useful even at the extreme fighting ranges of the various classes of guns.

Spotting, even at long ranges, is as accurate as gun-fire from shipboard, including the combined error of gun, ammunition, and pointer. That is to say, if we had a perfect gun and a perfect pointer, a spotter should be able to put him on the target in three or four shots, even at long ranges.

As a method of establishing the range by gun-fire, spotting is superior in every way to the establishment of a fork, sometimes called the "Bracket method".

Whitecaps have little effect upon the accuracy of spotting by the horizontal method.

Twelve-power stereo binoculars are the most efficient of any glasses tested for spotting, though it is thought that 20-power stereo-binoculars of as large a field as practicable should be procured and given a test. High power glasses are not, however, essential, as excellent results up to 3,000 yards have been obtained by unskilled enlisted men using ship's glasses.

Spotting individual shells when several guns are firing.- Following a 6-inch shot from a certain individual gun is entirely practicable when all guns are firing, and after a little experience it would be less accurate than spotting when one gun is firing, only on account of the effect of the smoke and splash. There is no difficulty in identifying the shell from any particular gun and in following it throughout its flight.

Best position.- Spotting from an elevated position is usually better than lower down, owing to the interference of smoke from the other guns. The upper foretop was the only place where no record was made of interference from smoke, and would therefore probably be the best place for the fire-control officer, so far as non-interference from smoke is concerned.

A division officer on the deck above his guns could nevertheless probably spot his shots with a great degree of accuracy and thereby control his fire during action after communication with the fire-control officer had been broken. To do this he should select some one gun (and preferably the one next to leeward of his position) and follow its shots and, by altering the sight-bars of all the guns of his battery to conform to that gun, bring his shots so the center of impact is on the target.

Experience necessary.- The great improvement in the ability of all observers to follow shots after the first experiment demonstrates the necessity of experience at spotting when all guns are firing. This experience can be obtained only at fighting-efficiency practices. Exercise of the officers at spotting should be considered as an important part of every practice where guns are firing, especially all practices where all guns are fired at once. It is only at such times that officer can gain the experience necessary to observe shots with sufficient ease and assurance to enable them to control the fire of their on guns in action after communications are all shot away.

Comparison of results with long-range spotting.- The results obtained at this 2,000-yard range could hardly be expected to be duplicate at long ranges, as, owing to the time of flight, there would be more chance for interruption from smoke. Still, this is simply a matter of relative accuracy of spotting at various ranges and in nowise affects the soundness of the principle.

General conclusions from all spotting tests.- From the results of the various spotting tests, showing the accuracy with which spotting can be done at all ranges when guns are firing singly, combined with the results of spotting tests where several guns were firing simultaneously, which shows that spotting can be done under those conditions with great facility, the board is of the opinion that spotting is useful not only for target practice, but must be regarded as of real value for use in action. This will be particularly true in the later phases of an action when range-finding devices and the interior communication system may reasonable be expected to be broken.

In such cases spotting may be most successfully used from a position sufficiently elevated to avoid the effects of smoke and gases, but it will, in all probability, even be practicable for a division-officer, isolated by the interruption of his communications, to employ it, though with somewhat greater difficulty in controlling the fire of his own group of guns.

MISCELLANEOUS NOTES ON SPOTTING

Long-range spotting.- The following extract from the report of an expert spotter, who spotted the long-range practice of a certain vessel, is of value. The ship was at anchor and guns firing singly:

The long-range practice of this ship was conducted with guns of the following calibers: 6-inch, 3-inch, 3-pounder, and 1-pounder. Seven strings were fired from the 6-inch guns on the first day at 4,100 yards. The fall of each shot was recorded by the spotter. Assuming the target-umpire's report as correct, the average error of the spotter in estimating the fall of shots was 82 yards. The errors in estimating the fall of particular strings ranged from 49 yards to 115 yards. On the second day, six strings were fired from the same guns at 4,050 yards. The average error of the spotter was 50 yards, the errors of strings ranging from 30 yards to 68 yards. The better results of the second day's work are due to better weather conditions and the experience of the previous day. With the 12-power stereo-binoculars there was no trouble in following the projectile throughout its flight, and most of the hits made were observed and reported in the correct squares. It was unnecessary to place the binoculars in front of the eyes until after the gun had been fired. Most of the spotting was done from the deck above the firing gun and a little to windward of it. It is easier to locate the fall of the shot by being several decks above the firing gun, but it then become more difficult to follow the shot after it has lost the sky for a background. It is preferable to have as much of the target as possible standing above the horizon. It is also much easier to spot the hits when most of the target stands above the horizon. It was found to be difficult to estimate the fall of shots that went considerably to the right or left of the target. The sliding leaves on the 6-inch guns varied from 3 to 5 knots with a wind of from 3 to 4 (Beaufort scale) blowing across the range.

The 3-inch were fired from a range of 2,200 yards. They were followed easily, and many hits spotted in the correct squares. The average error in estimating the fall of the 3-inch was about 60 yards. No doubt this average could have been reduced had more 3-inch pointers fired.

Little success was had with the 3-pounders or the 1-pounders at this range. The few shots that were picked up were lost before they reached the target, and we were dependent almost entirely upon the splash of the projectile. It ought to be observed that it is very important to spot guns of small caliber from a position below the guns. This holds for spotting guns of all calibers, but it is especially true of guns of small caliber. The small projectiles must be kept against a clear background as long as possible.

Re Fighting in the RJW, go here – link
- for a good summary. Keith Allen is a good man (i.e., not a fanboi with an agenda).

By 1906, Jackie Fisher was arguing that HMS Dreadnought, employing salvo fire with its uniform main battery armament of 12in guns and elementary FC methods could effectively engage and destroy an opponent at 6,000 yards.

By 1914 RN Battle Practices were being conducted at 8,000 yds (highly orchestrated exercises conducted pretty exclusively under fine weather conditions).

On the eve of WW1, Beatty had to apply for special permission to conduct a long range practice shoot with his BCs at 14,000 yds.

@ Blutarski:

That is some good information that I had not seen before! Thanks for posting that.

One of the things that struck me in this document was that things like variations in powder indexes and temperature, inconsistencies among projectile weights, deviations of parallelism between gun-sight and gun bore, defects in vessel construction regarding proper vertical and horizontal alignment of the gun turn-tables both with respect to true verticality and with respect to one another of the ship's various gun-mounts were just starting to be studied in 1904/1905 (at least by the USN); the importance of precision scientific calibration of guns, ammunition, sights and mounts had hitherto not been understood.

B

I haven't heard of this half-danger space before. I assume 2 x half-danger space equals danger space.

There are a number of excellent books on this thread

TMP link