Naval gunnery accuracy - question for M. Jurens

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Francis Marliere
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Re: Naval gunnery accuracy - question for M. Jurens

Post by Francis Marliere »

I am talking about this article.

Regards,

Francis Marliere
Byron Angel
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Re: Naval gunnery accuracy - question for M. Jurens

Post by Byron Angel »

Francis Marliere wrote: Gentlemen,
The article deals with USN fast battleships gunfire. Are things different for other warship types (cruisers, destroyers, etc.) and / or other navies (RN, DKM, etc.)? In other words, is it possible to extrapolate from the article hit chances for a USN cruiser or a foreign battleship ?
..... IMO, the answer is no, due to differences in the ballistics of the gun batteries of the several ship classes you mention and differences in fire control technology among the various navies.

I may be mistaken, but I think that in some night battles (Tassafaronga especially), fire control radar didn't perform well and locked on shell splashes rather than on the target. If that did really occur, how often ?
..... The issue of fire control radar performance can best be summed up as "the devil is in the details". It was a great deal more complicated than simply pointing the radar and banging away. The contemporary Tassafaronga battle reports were wildly optimistic about the effects of their shooting; even the naval intelligence study on Tassafaronga done later in the war, although much more reserved, still over-estimated the effectiveness of radar-controlled. A more objective assessment, written with the benefit of good data from the Japanese side, is "The Battle of Tassafaronga" by Russell Crenshaw; it is an excellent study of this battle. Also "U.S. NAVY AGAINST THE AXIS - Surface Combat, 1941-1945, by Vincent P. O'Hara is very valuable.

BTW, the USN Office of Naval Intelligence combat narrative of the Battle of Tassafaronga is available on the web. Can't remember where I found it, but a search should turn it up without too mch difficulty.

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Dave Saxton
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Re: Naval gunnery accuracy - question for M. Jurens

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Francis Marliere wrote:I may be mistaken, but I think that in some night battles (Tassafaronga especially), fire control radar didn't perform well and locked on shell splashes rather than on the target. If that did really occur, how often ?

There is a rather small sample of actual combat examples of radar dependant shooting from WWII, and from among those the MK3/MK4 directed shooting (as at Tassafaronga) is for the most part very dissapointing. The best WWII combat example of radar dependent shooting- indicating what radar direction can achieve- occured only 31 days after Tassafaronga. This was the Hipper's shooting at destroyers at Barents Sea.
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.
Francis Marliere
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Re: Naval gunnery accuracy - question for M. Jurens

Post by Francis Marliere »

Dave Saxton wrote: The best WWII combat example of radar dependent shooting- indicating what radar direction can achieve- occured only 31 days after Tassafaronga. This was the Hipper's shooting at destroyers at Barents Sea.
Could you please tell more ?
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Dave Saxton
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Re: Naval gunnery accuracy - question for M. Jurens

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First it must be understood that the battle took place for the most part during the polar night. At that time of year in the artic the sun does not rise above the southern horizon and it remains dark for almost 24 hours. There is only a brief period of twilight from approx 11:30 hours to Approx 12:00 when the southern horizon is brightened. The visibility was further hindered by a low lying fog or haze known as artic sea smoke. This is caused by the air temperature falling below that of the sea. The Luetzow KTB recorded the temperature as -23*. There were also blinding intermittent snow storms. When Tovey filed his official report he noted that because of the extreme weather conditions the optical fire control equipment had been rendered useless forcing reliance upon radar for range finding. The same difficulties applied to the Germans as well, and there are reports that the Hipper’s optics were iced up.

At about 0830-0900 the German destroyers Eckoldt, Z28, and Beitzen made radar contact with the convoy and the British destroyer escorts at the rear of the convoy which was on course due east. At 0904 the Hipper, which was 35,000 meters away to the north, turned south.

At 0918 from a range of 29,000 meters Hipper began to track the convoy with radar and altered course to the east.

At 0922 and 0923 Hipper located with radar and began tracking the destroyers Obdurate and the Achates at ranges of 18,000 meters. Kummetz altered course slightly to the south east.

At 0927 Hipper located a third enemy destroyer, the Obedient with radar.

At 0930 the German destroyers attempted a torpedo attack on the British destroyer Obdurate (which went unnoticed by the British) and the Eckoldt then opened gun fire on the Obdurate from a range of 10,500 meters.

At 0930 Kummetz ordered the German destroyers recalled to avoid confusing them with the enemy, for Hipper’s radar and gunners, as friend from foe could not be determined visually in the conditions.

At 0939 the Hipper turned more toward the southeast and opened fire on the destroyer Achates from a range of 15,100 meters. According to Ohare, the opening salvo produced a straddle and a hit. The Hipper fired only a few more salvoes at Achates at this time, all of which straddled.

From 0940 to 1009 hours Hipper only fired five or six intermittent straddling salvoes at individual British destroyers, as it attempted to draw the British destroyers away toward the north while forcing the convoy to turn away toward the south -where the Luetzow and three German destroyers were awaiting to attack. Kummetz succeeded in this intent.

At 0946 the Hipper altered course toward the northeast.

At 1015 the Hipper fired one salvo at the Obedient from a range of 15,000 meters which straddled.

At 1016 the Hipper opened fire on the Onslow, scoring four 8” direct hits out of 48- 8” rounds expended from a range of 12,000 meters. The Hipper ceased fire at 1018 and altered course toward the southeast.

At 1022 and 1024 the Hipper fired one salvo each at the Onslow and the Orwell.

At about 1028 the Hipper while in the mist of a blinding snow storm detected a radar contact to the east at a range of 16,000 meters. This turned out to be the minesweeper Bramble.

Kummetz sent the destroyer Eckoldt to finish off the Bramble while the Hipper turned away toward the north east at 1040, then toward to the south at 1046, and then toward the southwest at 1051, then increasing speed to full speed.

At 1114 hours the Hipper opened fire on the Achates from the range of 17,750 meters. According to Ohare: “For the second time in one day the Achates was hit by Hipper’s opening salvo” (I’m paraphrasing as I don’t have this reference handy). The Achates would sink from the damage received. At this time frame according to British records, the visibility was 7 miles or about 13,000 meters.

At 1118 hours the Hipper claimed straddles on the destroyer Obedient from a range of 16,100 meters.
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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Dave Saxton
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Re: Naval gunnery accuracy - question for M. Jurens

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Here's some of what L Brown (WWII radar authority) wrote about the radar directed shooting by both British and Germans at Barent's Sea.
Naval battles are complicated by continual changes of position and confusion about who is an enemy; they are consequently complicated to describe. The details of the attack and defense of JW-51B need not concern us here.....British radar range only extended to 10km*, and the opening of the fight followed the visual sighting of three destroyers of the Hipper group. As gunfire erupted from both sides during the next few hours radar was used effectively for ranging, but none of the equipment present allowed blind fire**....The confusion of identity was not helped by IFF as the few sets installed generally did not respond. Radar ranging made fire by both sides remarkably accurate, and initial fire was invarably close.....ship commanders kept radar reports in mind continually. Both sides were fortunate in having equipment that experience had made reliable. Only one set,a Type 273 of the Jamaica, failed as result of the ship's own gunfire. Both sides had well trained operators and mechanics.....radar's main contribution was to make the battle bloodier. The Germans lost a destroyer with all hands, and Hipper suffered damage with casualties. The British lost a minsweeper with all hands, a destroyer with svere loss of life and destroyers damaged with moderate loss of life. All this came from brief but accurate cruiser fire......
*According to Tovey's report the 10cm Type 271 radars on the British destroyers could not acquire and track the targets on their own but had to be put on the targets following visual sighting. Afterward they could hold the Hipper to a max range of about 16,000 yards.

** At the time Brown went to press this was thought correct, but since then new evidence has come to light which indicates that the German radar was upgraded with lobe switching, which is required for blind fire. Nonetheless, the German cruisers did engage in blind fire that day. There remains some question if the British 50cm sets on the cruisers were M models with lobe switching or not.
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.
dunmunro
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Re: Naval gunnery accuracy - question for M. Jurens

Post by dunmunro »

Dave Saxton wrote:
*According to Tovey's report the 10cm Type 271 radars on the British destroyers could not acquire and track the targets on their own but had to be put on the targets following visual sighting. Afterward they could hold the Hipper to a max range of about 16,000 yards.
Where did you read Tovey's report?
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Re: Naval gunnery accuracy - question for M. Jurens

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Dave Saxton wrote: *According to Tovey's report the 10cm Type 271 radars on the British destroyers could not acquire and track the targets on their own but had to be put on the targets following visual sighting. Afterward they could hold the Hipper to a max range of about 16,000 yards.
..... I'm not sufficiently well versed in the performance characteristics of the Type 271 to say for certain whether they technically suffered from an absolute inability or simply a very high degree of difficulty with respect to initial target detection and acquisition. However, for what it's worth, USN experience in the Solomons campaign showed that initial surface target detection and acquisition was almost always performed by SG surface search radar, with the FC radar having to be "coached" onto the target. Once the target had been acquired by FC, it could generally be tracked satisfactorily. One potential tracking problem, however, was when the FC radar was set to a narrow range gate on a high speed target that suddenly underook radical evasive maneuver; such a target could often run right out of the range gate and disappear from the screen.

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Re: Naval gunnery accuracy - question for M. Jurens

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@ Duncan:

Howse includes a portion of it. I don't know if or where it may be available online?

@ Byron:

Type 271 was a centimetric surface search set. It was similar to SG, but did not utilize PPI indication at this time. Like SG it radiated a 6* wide beam on 9.8cm wave length. The Antenna consisted of two horns (nick named the "cheese") located inside of a round plastic and wood container called the lantern. They may have been having problems with weather attenuation that day.

The British cruisers that day had a similar surface search set known as Type 273. Type 273 differed from 271 by having two parabolic dishs installed inside the lantern, and it was naturally mounter higher up on the larger superstructures. Sheffield detected the Hipper at a range of 20km. But the British surface search radars failed to detect the destroyer Eckoldt as it attempted to join the British formation.

The Eckoldt had mistaken the British cruisers for the Hipper and another German destroyer in the soup as it returned after sinking the minesweeper Bramble with a torpedo about 15km to the eastward of the British cruisers current location. The Eckoldt had began tracking the British formation on radar and mistook them to be the Hipper group it was suppossed to catch up with and rejoin. At 1148 hours after completing a 180* turn to almost due east, the Sheffield first sighted the Eckoldt coming straight on only 4,800 meters away. The British cruisers blew it out the water as it continued to close to a few hundred meters. The Eckoldt remained under the impression the Sheffield was the Hipper and did not launch torpedoes or return fire.

The British warships were also equipped with Type 286P surface search sets. The Type 286 was a conversion of the 150cm ASV II airborne radar, originally with a fixed antenna. Norfolk had a 286 with fixed antenna during the Bismarck chase, but it didnt prove really helpful then. Tovey reported that the 286 sets at Barents Sea proved completely useless.

The British firecontrol radars were the 50cm Type 284/285 sets. These radars produced a beam 4.5* wide, also without PPI presentation. They also normally did not use range gating like the USN FC and FD. Tovey in his report had high praise for the performance of the 50cm British radars that day.
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: Naval gunnery accuracy - question for M. Jurens

Post by dunmunro »

Dave Saxton wrote:@ Duncan:

Howse includes a portion of it. I don't know if or where it may be available online?
.
The RN CLs were probably using their Type 273 WS radar in Warning Surface mode, giving all round coverage, initially to detect and surprise Hipper, but then switched them into Gunnery Surface (as they had an excellent ranging panel, according to Tovey) mode as they engaged Hipper, and thus failed to detect Eckholdt, but this was a failure of doctrine, not equipment. Tovey implies that visual visibility probably exceeded the typical DD type 271 radar range of ~7 nm for much of the battle, but once acquired Achates was able to hold Hipper on Type 271 out to 8.5 nm, was which probably near the maximum range from a DD.
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