Practical ranges

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alecsandros
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Re: Practical ranges

Postby alecsandros » Tue Dec 11, 2012 6:34 am

Neoconshooter wrote: Again, gun fights at short range are nor similar to those at long range. At ranges where the side armore must per perforated to inflict significant damage, it takes many hits to sink a BB, even an old one. But at long range, all hits will perforate the deck armor.


I also think so - that's why I mentioned the hit on Musashi's boiler room.

The problem is how likely such a hit might be (as there are zero occasions when such a thing was achieved). Plus, WW2 combat and WW2 navy doctrines show that any range > 27-28km is "extreme", and firing beyond it was simply a waste of ammo (and this was proved several times)
Moreover, a ship isnt' a floating bathtub filled with explosive charges. Only some small portion of the internal volume is dedicated to storing powder charges, so there is only some small volume of vulnerability.
HItting the machinery spaces also causes damage, but as we know all BBs had reserve power, and could mantain their speed even with part of their machinery inoperable.

Again, an agressive captain would probably open fire at 30km+, conditions permiting. IF he would manage to obtain a hit though is a matter of pure luck, as the shell's falling angle, salvo dispersion and enemy movement would make actual hits extremely improbable...

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Rick Rather
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Re: Practical ranges

Postby Rick Rather » Thu Dec 13, 2012 7:21 pm

sandym wrote:Hmm, remember that New Jersey was sent to bombard Lebanon in 1984 and missed its targets by as much as 10,000 yards. In fact, it didn't hit anything it aimed at.


My recollection is that she knocked-out 30 Syrian gun batteries and the Syrian army HQ in Lebanon.

A BB FC explained to me that she had one "bad barrel" (the nature of the problem was described to me but the beer I was consuming at the time interfered with both my comprehension and memory). This barrel caused the over-publicized (compared to what else was happening) misses.
Just because it's stupid, futile and doomed to failure, that doesn't mean some officer won't try it.
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Re: Practical ranges

Postby paulcadogan » Fri Dec 14, 2012 2:07 pm

Neoconshooter wrote:How many ships besides Hood have been sunk by plunging fire?


Hood was not sunk by plunging fire - she was sunk at 16,500 yards - a flat enough trajectory that it would have been virtually impossible to reach the magazines through exclusive deck penetration.

Bretagne, I believe the only other capital ship sunk in WW2 by a direct shell hit causing a magazine explosion , was hit at about 17,500 yards.
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Thorsten Wahl
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Re: Practical ranges

Postby Thorsten Wahl » Fri Dec 14, 2012 7:56 pm

the plunging hit came at 16min:40sec here
free falling shell :cool:
http://www.youtube.com/watch?v=KUfN2hg8 ... re=related
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!

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Re: Practical ranges

Postby paulcadogan » Sat Dec 15, 2012 2:35 am

Thorsten Wahl wrote:the plunging hit came at 16min:40sec here
free falling shell
http://www.youtube.com/watch?v=KUfN2hg8 ... re=related


:lol: :lol: :stubborn: :stubborn: :negative: :whistle:

Good one!
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delcyros
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Re: Practical ranges

Postby delcyros » Sat Dec 15, 2012 9:18 pm

At ranges where the side armore must per perforated to inflict significant damage, it takes many hits to sink a BB, even an old one. But at long range, all hits will perforate the deck armor. In addition, the target area is much larger than at short range.


Some aspects to consider:
[I] Long range hitting of maneuverable targets from mobile platforms is not a trivial task
[II] Projected target area is SMALLER for long range than for short range targets owing to the relationship between target area and angle of fall geometry.
[III) confirmed armour deck hits by 11in or larger are extremely rare in both world wars compared to hits on superstructure, exposed vitals (like turrets, barbettes, CT and other exposed equipment like RF) or hull hits (involving belt armour). Even diving hits were more frequent than deck armour hits.
[IV] There is a range of obliquities, where deck armour hits may be blinded due to insufficient fuse sensitivity at high angles of attack. By ww2 only very few grace fuses (the USN had no) were capable to work with some reliability at obliquities of 70 deg and between 60 and 70 deg obliquity reliability was poor by all fuse designs.
[V] I am still looking for a single case where a cruiser or BB in either war was sunk from what has ultimately been described and confirmed as a main armour deck penetrating hit.

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Re: Practical ranges

Postby Byron Angel » Sun Dec 16, 2012 3:02 pm

Delcyros raises a good point. Conventional wisdom has it that the incidence of decks hits exceeds that of side hits beyond 15deg angle of fall (assuming line of fire to be more or less normal to target ship keel line). But that assertion is very much an arbitrary and somewhat misleading trigonometric generalization. It takes into consideration only beam versus freeboard and effectively defines "deck hit" as any hit that strikes the weather deck, as opposed to reaching armored deck; there is a vast difference between these two cases.

The only proven occasion of successful penetration of a heavily armored capital ship protective deck that comes to my mind is the hit made by USS MASSACHUSETTS upon JEAN BART at Casablanca, which reached and detonated within her (thankfully empty) aft 6in magazine space.

B

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Re: Practical ranges

Postby alecsandros » Sun Dec 16, 2012 4:53 pm

Byron Angel wrote:The only proven occasion of successful penetration of a heavily armored capital ship protective deck that comes to my mind is the hit made by USS MASSACHUSETTS upon JEAN BART at Casablanca, which reached and detonated within her (thankfully empty) aft 6in magazine space.
B

A small note: IIRC, there were 2 x 16" shells fired by Massachussets wich managed to perforate Jean Bart's horizontal protection...

Another possibility, allthough small, would be the explosion of Bretagne... under fire from 15" guns... firing at 16km...

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Re: Practical ranges

Postby paulcadogan » Sun Dec 16, 2012 7:06 pm

alecsandros wrote:Another possibility, allthough small, would be the explosion of Bretagne... under fire from 15" guns... firing at 16km...


Bretagne was pretty much broadside on to the incoming shells so given the trajectory at that range, it was most likely side or below the waterline pentetration.
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sineatimorar
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Re: Practical ranges

Postby sineatimorar » Sun Jan 20, 2013 10:06 am

The answer is in 'line of sight'. Visual range from the highest point of the ships superstructure ( fore top). On average the for western and European battleships maximum effective range was around 23,000 meters in perfect conditions. Add to this is the height of the targets fore top would add to 'sighting distance' and the use of scout planes changes this distance again.

To this let us add some statistics & and figures to this question. Average flight time at 35,000 meters is around 70 second or 1 min 10 secs. In that time the target radius of possible movement at 30 knots is 1080 meters and published accuracy at 27,000 meters is between 1.4% to 2.7% depending on target orientation.

Basically what it all boils down to is the effective combat range for a purely naval combat between two combatants is the visual range on the day or night of combat. Purely going on empirical evidence from actual combat this range is around 26,000 yard to 27,000 yards in the Atlantic. The circumstances in the case of Japanese warships are unique due to their pergola style conning towers which have a greater line of sight but did nothing to increase the small chances of hitting their targets.

The type 279 radar on British and the equivalent American units were mounted on the masts that allowed for a greater possible range to open fire at ranges of 30,000 meters but this was about as effective as a dizzy blindfold man firing a 12 gauge shotgun at a barn door from 100 paces. There is no possibility of spotting fall of shot from the ship without a separate spotter.

It is really a technical nonsense to be considering accurate firing at any range above 25,000 meters in a ship to ship action. Any hit is due purely down to simple luck.

Another way to put it is a average .22 long rifle hunting rifle has an effective range of about 100 meters. The bullet is considered lethal or dangerous out to 5 km. With improvements in sighting and other factors you could stretch the effective range to 200 meters.

It is the same with any artillery system really, not only do you have to see your target, you have to see where your shell lands to correct the error if any exists.

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Re: Practical ranges

Postby alecsandros » Sun Jan 20, 2013 7:57 pm

Hello sineatimorar,

I would add to your post the capabilities of mid-to-late war radar, many of which could determine the fall of shot on the screens.

USN, RN and KGM all had radars with this capability, making accurate firing at night very realistic.

At Surigao Strait at night, West Virginia obtained a firing solution on Yamashiro at 27000y, using her advanced radar systems, but her captain waited until 22.000yards to open fire. The first salvo was a straddle, with at least 1 hit on the pagoda mast.

Extrapolating to even more advanced radar and firing systems, available late war, such as the the systems on Tirpitz or Iowa, it was theoreticaly possible to engage a target as far out to 35km.

However, the foloowing should be considered:
- without visual confirmation, it was difficult to tell friend from foe
- radar jamming could render radar plot allmost useless
- as you said, at long range time of flight of sehll becomes quite long, and a 30kts target can travel a great distance in any direction, not necessarily in the path of the shell.
- scatter of shells is quite large at long range.
- angle of descent is large at long range, leading to smaller hitting space...

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Re: Practical ranges

Postby Dave Saxton » Mon Jan 21, 2013 4:47 am

sineatimorar wrote:The type 279 radar on British and the equivalent American units were mounted on the masts that allowed for a greater possible range to open fire at ranges of 30,000 meters .

The problem with mast mounted air warning radars such as Type 279, Type 281 (All but KGV of the KGV class had 281 rather than 279) and American SK (could add Japanese Model 2mod 1) is the vertical lobes structure of metric radar. This really limited their effective range to a surface ship to 20km in most cases.

Nevertheless, the radar horizon is not quite the same as the line of sight horizon. I don't have the equations handy but I have done some calculations. Decimetric and Centimetric radar, given a 33 meters mounting height for the transmitting antenna, can be effective beyond 40km in terms of radar horizon. One notes that Duke of York's Type 273Q detected the Scharnhorst at 42km. This wasn't a firecontrol radar however. The problem of mounting height of the radar at sea was more a problem of losses due to absorption of the signal by the sea, and spectral reflection by the sea scattering the signal in the case of centimetric wave lengths, moreso than radar horizon. An example is the British radar for submarines which combined with the low mounting height and the vertical lobes structure of its 150cm wavelength meant that it had a max range to a battleship of 3,500 yards.

would add to your post the capabilities of mid-to-late war radar, many of which could determine the fall of shot on the screens.

USN, RN and KGM all had radars with this capability, making accurate firing at night very realistic.


There's a lack of clarity about the spotting question. Some American manuals say the Mk8 could spot BB caliber splashes only to 20,000 yards. However, Surigao seems to point out that this was a rather conservative stat. Manuals say that Mk3 could spot for range and sometimes for bearing. However at Guadalcanal, Lee noted that attempts to use any of the radars to spot for fall of shot actually failed completely. The Duke of York had to cease fire at 19,500 meters range at North Cape, because Type 284M could not the fall of shot. British documents do indeed state that Type 284M could not spot the fall of shot. The late war Type 274 could not spot the fall of shot either. It could not pickup shells falling outside the beam, which was less than 1* wide. This is probably why some stats state that Type 274 had a max range to a BB of 33,000 yards or 30km. Others sources state 43,000 yards. But if the beam is too narrow it may not get all of a large warship in the beam and the large warship will have the radar cross section of a smaller ship. In 1947 Vanguard received an add on radar for spotting and RN BBs finally featured the capability to spot for fall of shot using radar alone.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Practical ranges

Postby alecsandros » Mon Jan 21, 2013 6:36 am

Lutzow's main battery firings against Obdurate at Barents Sea, at 15km, through dense fog, seems to indicate the use of a very precise tracking and spotting system, with no visibility.

Also, from what I understand from Bill Jurens and Garzke's analysis of the NOwaki chase, fall of shot was plotted on the radar screens throughout the engagement, so at ranges in excess of 32km.

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Re: Practical ranges

Postby Dave Saxton » Mon Jan 21, 2013 3:07 pm

alecsandros wrote:Lutzow's main battery firings against Obdurate at Barents Sea, at 15km, through dense fog, seems to indicate the use of a very precise tracking and spotting system, with no visibility. .

The Luetzow's shooting at Barents Sea is instructive about Seetakt's capabilities for blind firecontrol circa 1942. When Luetzow finally opened fire at 11:38 hours it did so using an optical firing solution initially. But spotting the fall of shot was soon impossible optically, because after the first salvo the target was soon hidden by a heavy snow squal, and splashes from shots of the secondary battery falling short also obscured the target. The range was ~16,000 meters and increasing. The Luetzow then went over to full radar direction. We know that radar was being used to spot the fall of shot, because it was stated that the radar operator had some difficulty spotting, caused by the shock of each 28cm salvo making the indicator "jump". After six minutes they shut down the radar, serviced it, and brought it back into the battle in five minutes. There after it performed well; allowing Luetzow to accurately target the Obdurate.

Seetakt was well set up for spotting the fall of shot using the fine range CRT. The target pip was positioned right in the middle of fine range CRT screen. The amount of range could be zoomed in or out so that there was say 150 meters presented short or long of the target and the splashes short and long of target easily observed.

Spotting for bearing could be done on the fine bearing indicator. The target pip was also positioned in the middle of screen. If the bearing track was off line to the left or the right then the target pip was presented off line to the left or to the right of the center line. Accuracy was within 0.1*. Shell splashes off line could be presented the same way. The bearing resolution would be that of the ½ power beam width, however. (Luetzow’s Seetakt antenna was 16 wavelengths wide)

Spotting the fall of shot for the British Type 284 was problematic because of the nature of the instrumentation. It was a simple A-scope which presented no bearing data. The aim of the antenna was known to be on line or off line by if the target trace flickered or held steady. Obviously spotting for bearing using the radar alone was not possible. Spotting for range was only possible if the shots fell outside of the range resolution window of 150 meters.

Also, from what I understand from Bill Jurens and Garzke's analysis of the NOwaki chase, fall of shot was plotted on the radar screens throughout the engagement, so at ranges in excess of 32km.


As I understand it the shooting at Nowaki was initially done with optical firing solutions (probably radar ranged). But once the range increased to extreme it was switched over to full radar control.

American Mk8 radar was well set up for spotting the fall of shot on its B-scope. Here the target pip was held in the middle of the screen for both range and bearing. Splashes picked up relative to the target were presented for both range and bearing relative to the target. MPI was easily seen. MK8 had only a 2* wide beam. The transmitted beam was panned back and forth through a wide arc and so targets could be discriminated for bearing to a resolution of 2*. The discrimination for range was about 65 meters. MK8mod2 gave a repeater B-scope to the firecontrol computer room. (Mk8mod3 was a Mk8 converted to Mk13)

The British 10cm firecontrol, Type 274, introduced in May 1944 could not spot the fall of shot. The British were more concerned about jamming and other counter measures than the Americans. Type 274 didn’t pan the transmitted beam like Mk8 and Mk13, so that the lobing frequency could not be picked up by the enemy and easily jammed. Only the receiving antenna was lobe switched. But this meant it could not see splashes of shots falling outside the very narrow transmitted beam.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

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Re: Practical ranges

Postby alecsandros » Mon Jan 21, 2013 4:39 pm

Aaa, thank you very much for a much detailed post !

I thought Lutzow acquired the target (Obdurate), opened fire and continued to shoot at it using radar only.
But now that I think of it, it's nonsense, as the "target", from Lutzow's stand point, could easily have been a German destroyer. :D So optical confirmation was a must.

Another word on this, allthough it doesn't concern radar plot of fall of shot, but it does concern firing accuracy: both Hipper and Lutzow fired remarkably accurate salvos at Barents Sea, despite the weather conditions (rough seas, poor visibility, etc). This shows that the fire control system used on German capital ships was very precise and capable of very fine tuning...

[Hipper showed her impressive armament quality before, during the skirmish with HMS Berwick...]


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