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I was aware that section 2 does deal with the 4in gun, but this particular extract refers to all dead times, for both claibres, , not just not just the 4in.
We dont know about the 4.7 twin, but it has the same published rof as the 1936 models. Power ramming still requires hand loading and can involve innefficiencies because of the poor placement of the shell hoppers, so I have to disagree with you. the power rammer might add or improve fireing cycle by 1-2 seconds over the older mounts but that still brings it in at somewhere below 12 rounds per minute. Given that 12 is already an indaequate number, the conclusion whether it be twin mounting or no, remains the same.
If as I suspect the older models at non-optimal elvations can only fire at around 6 rpm, and power ramming improves that practical rof by say 1-2 secs, then you might get 8 rpm. still within the original estimate for practical rof of 4-8 rpm. 4 for the really old versions, 8 for the newer twins.
Sorry, still dont agree with you. Far too rose coloured a view of the RN capabilities in my book.
The day by day hum drum of her "working up" period, prior to her joining the Home Fleet at Scapa Flow, would make most uninteresting reading except the mention that she became, by virtue of her latest type radar, exceedingly rapid rate of gunfire (16 round per minute) and high speed, a very efficient ship. An efficiency that was to be a saving grace to her in her hectic times to come.
http://www.naval-history.net/WW2Ships-Charybdis.htm
A lot of truth in this but the 20mm were added pretty quickly, when would depend on the ship and availablity. I don't disagree with your description of the value of the effectiveness of the single 4in added in some destroyers.The RN didn't have pom-poms, 20mm and 40mm bofors guns gathering dust that could be used to quickly augment destroyer AA, but they did have lots of older 3in and 4in guns that were not being used - sorry but that is the way it was. A 3 or 4in gun fired over open sights against an aircraft is no more accurate than any other gun fired with the same method; a pom-pom or bofors would have a much better hit probability because of the high RoF.
Look, I've provided abundant data regarding the RoF
5 rounds in 17 sec for Basylisk in 1930
180 salvos from Kimberly at Narvik, most with a 5 sec loading cycle
Ilustrious was armed with 4.5 in guns. a completely differnt kettle of fish and not a destroyer anyway 12 rpm is still too slow to be effective15rpm for the 4.7in Mk VIII- 3000 rounds from Illustrious at an average of 12 RPM
16 RPM from Scylla...all these guns had essentially the same loading tray system, except that the last 4 all have power ramming.
It is time for you to get off this pot and accept the facts .
There is no rose coloured views here , just a lot of hard digging and research.
And all of it, for one reason or another has been misinterpreted.
peacetime conditions, optimum elevation, no turret elevation or training to worry about. I bet they were a crack gun crew.
Kimberly certianly did engage moving targets and did so while moving rapidly herself, and again I reduced the AA rof to 10 rpm in my calculationsNot in an AA role. and against targets not really moving at least some of the time. Not relevant to what we are discussing
Illustrious was armed with 4.5 in guns. a completely differnt kettle of fish and not a destroyer anyway 12 rpm is still too slow to be effective
Scylla was armed with 4.5 inch guns. ive never questioned the rof of the 4.5 gun. Scylla was a cruiser. youve claimed repeatedly that the 4.7 gun had the same loading tray system, but wont recognize or acknowledge that at least one source does not agree with you. Even on the basis of max rof, the 4.5 is rated at 20rpm, whilst the best 4.7s are rated at 12 rpm. how can that be the same?
I've produced evidence that the gun could fire at an average of 12rpm for very long periods and up to 16rpm.Britain
4.5"/45 (11.4 cm) QF Marks I, III and IV
(Marks 2, 3, 4 and 5)
Twin mountings of World War II: 12 rounds per minute per gun
Ive accepted the source material youve produced. what I have challenged, is your interpretation of those facts...
Charybdis was a cruiser, armed with the 4.5 in gun which I have already commented on. a different gun, with a different published max rof, and specifically developed to address the known weaknesses of the 4.7 in weapon. Again, if anything just serves to underline or provide background evidence that the 4.7 was not a good DP weapon, in any of its forms.
Benham opened fire with 5" anti-aircraft barrage"; initial range 5,000 yards (altitude 12,750 feet), and 20 m.m. fire.
1714 -- Enterprise observed to be hit by bombs.
1720 -- Ceased firing.
Of the approximate twenty (20) planes making the attack, which came within range of anti-aircraft batteries, nearly all were shot down in the vicinity of the Enterprise. Several of these planes were fired upon by this ship and adjacent ships in formation. About four (4) were seen to attempt to escape and were pursued by our fighters. The Enterprise appeared to be the sole target of the attack except for four (4) dive bombers, who, attempted to bomb the North Carolina, and were promptly shot down.
There were no casualties to either personnel or equipment of this vessel.
Ammunition expended:
5"/38 - 109 rounds
20 m.m. - 510 rounds
http://www.ibiblio.org/hyperwar/USN/ships/logs/DD/dd397-ESols.html
Comment on material:
There were no material failures.
The main feed pumps are in such a condition, that their reliability is uncertain. Early installation of new main feed pumps, already ordered by Bureau of Ships, is necessary for battle efficiency.
The main generators overheat excessively in tropical waters, when the load of battle requirements is placed on them. An improved cooling system is urgently required.
The open-sight for director pointer is inefficient. An improved design is needed to aid in getting director and guns on rapidly moving air targets.
The temporary installation of number two 20 m.m. gun on the midship deck house, frame 99, enabled that gun to fire effectively, twice as many rounds as guns 1, 3 4.
During the greater part of the first eight months of war operations this ship has been one of a carrier screen. This ship has only four (4) 5 inch and four (4) 20 m.m. guns. In both the MIDWAY and SOLOMON (STEWART) battles the need for additional anti-aircraft guns was readily apparent. It is again recommended that additional 20 m.m. guns, or, 40 m.m. guns, be installed; and if necessary for weight compensation, eight ( 8 ) of the sixteen (16) torpedo tubes now carried, be removed.
More interesting stuff from you, I wish I had a spare day or two to go through your books. One important observation, the USS Benham opened fire at 5000 yards at a target flying at approx 12,500 ft. Looking at the chart you included in posting 123, a JKN/Tribal using the twin 4.7 would have had to cease firing at about 7,500 yards and could only open fire at about 11,000. In other words the chances of being damaged by the 4,7 would be very slim as the destroyer only had about 35 seconds to get the range, and at the point of bomb release the bomber would have been untroubled.USS Benham at Eastern Solomons:
Some comments - note they they used "barrage fire" A JKMN class could have engaged the same target, but would have had to open fire before 6000 yds and she would have been able to place a barrage over Enterprise (which is what happened) that the DBs would have to fly through. Note the small ammo expenditure. This is the same battle where Crenshaw of USS Maury stated that they were unable to engage the IJN aircraft because of the ineffectiveness of the Mk 33 GFCS.
An observation on the Twin 4.5 and the Twin 4.7 mountings. There was one significant difference between them, the twin 4.5 used a fixed shell and the twin 4.7 a separate shell. This must have made fairly major changes in the loading arrangements
More interesting stuff from you, I wish I had a spare day or two to go through your books. One important observation, the USS Benham opened fire at 5000 yards at a target flying at approx 12,500 ft. Looking at the chart you included in posting 123, a JKN/Tribal using the twin 4.7 would have had to cease firing at about 7,500 yards and could only open fire at about 11,000. In other words the chances of being damaged by the 4,7 would be very slim as the destroyer only had about 35 seconds to get the range, and at the point of bomb release the bomber would have been untroubled.
The Enterprise radar lost track of the enemy group when it came within its minimum range, but, on the basis of previous tracking, radar plot reported at 1709 that "the enemy planes are directly overhead now!" In spite of this warning and the excellent visibility, the first plane was sighted after it already had entered its dive. Effective enemy plane camouflage and the fact that the first dives were made on the Enterprise from the port quarter, out of the sun, probably accounted for this belated visual contact. In the case of the Enterprise, the first plane was sighted at 12,000 feet by a 20-mm. battery officer. Although the target was well beyond effective range, he promptly opened fire with one gun, thus calling the ships' attention to the attacker and giving them a point of aim.
HyperWar: The Battle of the Eastern Solomons [ONI Combat Narrative]
I was allowing time fior the shell to arrive as the 6,000 yard is the last shell burst. However the chart is very clear in that the time between the earliest shell burt and the last shell burst is about 35 seconds. It would be the shortest and least effective barrage fire in history.I checked the 4.7in engagement drawing carefully, and I get minimum range of about 6000 yds for 12750 ft altitude, but yes, potentially, there would be a few thousand yards where the destroyers would not be able to engage the aircraft with predicted fire, prior to the barrage.
... They dis carry out a number of Dunkirk style evacuations, but with heavy losses. I vaguely recall they undertook the evacuation of the Hango peninsula in Dewcember 1941.
The Russians actually had two categories of Desytroyers, which we might classify as leaders and then destroyers. DD Tashkent was an example of a Leader, and was, by most accounts, an exceptionally well designed ship.
I never said that the RN thought that 40 degs was enough!
What I've been saying is that 40degs is not useless and that most air attacks could be engaged by destroyers with 40 deg guns - anyone who takes the time to read Lundstrom and First Team will know that in almost every case USN destroyers with 40 deg elevation could have provided the exact same AA support as they did in 1942. The problem is that most people seem to think that aircraft simply materialized directly over destroyers (but only RN destroyers), and they were helpless if they couldn't shoot straight up! Of course this is complete nonsense.
It certainly was a sign of desperation, to add single 3in or 4in guns - the problem being that the 20mm oerlikon was not yet in UK or Cdn production, nor was the Bofors 40mm in a naval mounting, and the quad pom-pom was in very tight supply, whereas these 3in and 4in guns were sitting around gathering dust...and so they were hauled out of storage and added to RN Fleet destroyers. Later in the war, most of these ships had the gun removed and replaced by TTs once again along with a greatly strengthened CIWS.
...Here's Delhi's service record:
HMS Delhi, British light cruiser, WW2
note how she was tucked away in the Irish Sea during HARPOON and PEDESTAL. Hardly what you'd expect if she was supposedly the best AA ship in the RN...
I agree that from Tribals onwards RN DDs had reasonable AA capacity against TBs and level bombers attacking at fairly low altitude but the problem was that the high level bombers, usually not dangerous but IJNAF bombers had fairly effective bombing tactic against ships, after flying through the zone inside which the British early war DDs could fire at them could made the final stage of their attack completely unhindered by fire from those DDs, same goes with the dive bombers. Even late war RN DDs had fairly weak CIWS when compared to USN Fleet DDs Allan M. Sumner and Gearing classes had 12 40mm Bofors and some 12 20mm Oerlikons, those which had landed a TT mounting had 16 Bofors. Even KM DDs after Barbara mods had heavier CIWS than late war RN DDs and as had the late war IJN DDs with 20-28 25mm AAA guns, even if IJN 25mm was fairly light AAA gun and the 3x25mm mount had its problems. Of course KM needed much more AA defence than RN in Europe in 44-45.
Juha