British 1936-42 purchase options, logistics and export/import of military hardware

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British screw up with 5.25in gun & mount.
DP guns require a very careful balance and many navies leaned to the surface action side. The RN really leaned to surface action side with the 5.25 and the low rate of fire really hurt the AA capability of any ship that had them.
As designed the Dido's were supposed to have 5 twin 5.25 mounts and a single quad pom-pom on each side and either a quad .50 cal mg on each side or two twin .50s per side.
The 5.25 proved to have a firing rate about 2/3s what was hoped for and a single quad pom-pom per side was nowhere enough to handle large attacks (more than a few planes at once). While the 4in guns fired a smaller shell they fired about twice as fast.

One does wonder if they would have been better served by building slightly stretched Arethusa class ships and fitting the updated heavy AA of 8 four twin 4in mounts and the single quad pom-pom per side.

The 'power' of the 5.25 as an AA gun was largely an illusion. The ability to really hit a high flying airplane (or small group) from a moving ship didn't exist. Of course the ability of high flying airplanes to hit a moving ship didn't exist either. Both sides thought they could do better than they really could. Maybe, maybe, the 5.25 was better at discouraging snoopers at very long range. But at about twice the weight per twin mount/turret over the 4.5in mounts that was a high price to pay.

The US navy was pretty much a class by itself with the 5in/38. They had deliberately sacrificed long range surface fire capability for better AA (faster fire, quicker train and elevation movement). Just because you can elevate a gun to 70-80 degrees doesn't really make it an AA gun. Destroyers can't hit much of anything at 15,000-20,000 yds anyway, the hulls are moving around too much except in a dead calm. Pre radar they don't have big enough range finders to actual spot fire at those ranges and even their look outs are closer to water and moving around more (spotter in a destroyer crows nest?)
EwenS said:
So you can criticise S & C as much as you want, but as AA cruisers they were considered in some quarters as the best the RN had.
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This is quite correct in that the 4.5in mounts fired about 50% faster than the 5.25 mounts so even the DIdo's had their full 5 mounts and they fired at 8rpm that is 80 rounds per minute. The S & C could fire at 12rpm per barrel so times eight barrels that is 96 rounds per minute. Against an 4 mount 5.25 Dido with a firing rate of 64 rounds per minute we can see the advantage the S & C had. The much lighter 4.5 mounts allowed for more ammo and the RN elected to expand the superstructure for more volume to create space for personnel for flagship duties.
 
S&C don't appear to have carried significantly more ammunition than the 5.25" gunned ships.

In his British Cruisers book Friedman has the original Didos at 360rpg (Raven & Roberts say 340rpg) and both agree on 340rpg for the modified units. Friedman notes that in Nov 1939 S&C were to have an ammunition load of 400rpg.

During the war the type of ammunition storage was changed in all types of ship, allowing the carrying of more ammunition. I've not seen anything to indicate how that affected the various Dido groups.

The decision to equip them as flagship for Rear Admiral (Destroyers) was for several reasons. Firstly, they were a unique pair. Secondly RA(D) was unlikely to miss the extra firepower of the 5.25" amongst his 4.7" armed destroyers. Thirdly, they were more modern ships than the pair of Arethusas (Aurora & Galatea) already allocated to the task. Their release would then allow the whole Arethusa class to operate as a homogeneous squadron, something that in the event did not happen. As part of that flagship role they received a boat crane and extra boats amidships. So overall their displacement on completion wasn't hugely different from the 5.25" armed ships completing around the same time.

As for the Arethusa v Dido question, often ignored is that it was 10 gun barrels v 10 gun barrels.

Arethusa - 3 twin Mk XXI 6" capable of 60° elevation and 4 twin (After upgunning from single mounts) 4" Mk.XIX capable of 80° elevation.
Dido - 5 twin 5.25" Mk.II capable of 70° elevation
S& C - 4 twin 4.5" MK.III capable of 80° elevation.

All depends on how you like to dice & slice it
 
The 6in guns on the Arethuse don't make very good AA guns, they have to be lowered to at least 12.5 degrees and preferably lower to reload which is going to slow the book rate of fire at higher angles. They also have about 200 rounds of ammo per barrel and in 1940 they were issued 170 rounds of CPBC and 30 rounds of HE. An increase from the 1930s allocation of HE.
Of course in 1932-34 when they were designed and laid down they were expecting pretty much biplanes doing around 150mph as attackers, such was progress
The planes didn't progress quite as fast in the mid 30s but things changed a lot at the end of the 30s and in 1940-41.
On the other hand the British 6in was firing a 112lbs shell and has better AP performance, so it is a real dice & slice.
But the 5.25 was as not good as the 6in against ships and it wasn't as good as the 4.5 against aircraft and it may not have been any better against aircraft than the 4in.
A lot depends on fire control and when each caliber of shell got proximity fuses, which was not foreseen when designed/laid down.
Fire control was often much more limiting than the ballistics of the gun/s.
 
Getting back to tanks several major things have to happen in the mid 1930s.

1. Agree that tanks can actually be issued and shoot HE shells. If they don't do that it doesn't really matter what size the tank gun is until 1942, 75mm solid shot doesn't work on infantry, trucks, bunkers much better than 40mm solid shot.
2. Take the guys who are advocating that tanks (without HE) can run around on their own, overrunning positions and then just have infantry and AT guns show to relieve tanks of possession of the capture ground, and pound some sense into them. The tankers should not be seeing the infantry and artillery in their own army as a "us vs them" situation.
3. Take the guys who are advocating that tanks can drive around in "fleets" like ships at sea in large clear areas and shoot while on the move and take out their enemies and pound some sense into them.
They might want to consult with actual navy commanders and coastal fortification officers to find out how well moving ships do against stationary guns. The ships need to outnumber the stationary guns by a large amount.
4. If you really think you are going to be operating in large, clear areas, like the Salisbury plain.

Why do you think you only have to hit targets 600-800yds away? A gentlemen's agreement with the enemy?

There maybe other things that need doing.

This is a small, cheap tank.

This is small, but not as cheap and unless you are trying to overrun AT guns, it isn't actually much use so combat value for money spent is actually pretty low.
And this still needs so explaining

It is 1936 when the first one showed up. 6 men in a largish tank with not much more armor than the little 5 ton tank.
two of the crew had their very own personal gas chambers once they start firing the guns.
1936 was about the time the Germans were selling 37mm AT guns to anybody that could afford an extra large stein of beer.
They licensed the 37mm to at least 3 different countries and were selling German made guns to a lot more.
While the front of the tank would stand up to such antiques as these from about 200 yds.

many companies were trying to sell AT rifles. It is one thing to loose a 3 man tank to small AT weapons. Loosing a 6 man tank (or causing the tank to stop while they treated one/two crew members) to try to stay 'cheap' is a false economy.
 
This, thousand times.
From the era of Alexander, the better armies in the field employ the combined arms doctrine - be that cavalry + infantry + skirmishers, or cavalry + infantry + artillery. Thinking of oneself as the silver bullet that will just sweep the enemy from the battlefield, while other arms of the Army are in the wrong or are bad, was a dire mistake.

In the Army, absolve the prefixes of 'royal' for anything that is not the whole army. Just like there was no 'royal destroyers', or 'royal submarines' in the RN - only royal thing in the Navy was the whole Navy.

Shortround6 said:
1936 was about the time the Germans were selling 37mm AT guns to anybody that could afford an extra large stein of beer.
They licensed the 37mm to at least 3 different countries and were selling German made guns to a lot more.
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Again spot on.
Not just them, Austrians were selling the 47mm, and Czechs and Swedes were selling 37mm AT guns.
 
hobbes154 said:
OK, so since everyone is going straight to the nitpicking I'll take that as a "no" on any really big changes in trade patterns.
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If you're genuinely surprised by this you must be new here.

More generally if you think the historical build of "big gun ships" was the best use of resources at the time, I don't think either of us is going to convince the other.
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As tends to be mentioned when this is brought up, what aircraft (land or ship based) could do to big gun ships was different in mid war than in the mid 30ies.


If somehow the UK finds itself with spare capacity in the aero engine industry, my vote would be to pour more money into RR, and set up more shadow factories for Merlin, and later Griffon, production. That seems more likely to result in something useful sooner than setting up production of an engine previously not produced in the UK.
 
SaparotRob said:
That was their point, being anti-aircraft cruisers like the Atlantas.
Unless you meant they didn't build enough of them, with which I can agree
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Oh god no.

Atlantas had 2x as many of a better AA gun/mounting and even they weren't considered an unqualified success.

I mean given how stretched the British are I think it's exceptionally poor use of resources to build a new light cruiser with all its scarce armour and turbine machinery to carry 8 mediocre AA guns (even if you think new BBs and cruisers are worth building at this time which I don't).

You're either protecting capital ships, in which case put the AA guns on the capital ships, or you're protecting merchant convoys, in which case put them on something cheaper like this or this (ideally without the turbines).

EwenS said:
You clearly don't understand how that came about.
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Really? Are you psychic?

My understanding was that they were designed for 10x5.25" and built with 8x4.5" due to a shortage of 5.25". Which you have just repeated in far greater detail.

EwenS said:
The 4.5" gun was designed around 1935 .... It was 1942 before it was selected as a weapon to arm destroyers
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EwenS said:
So the guns and mounts fitted to S & C were not "destroyer armament".
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Seriously? You're trying to make some kind of point about the exact mountings on S&C not being exactly the same as those used on destroyers? (In fact the ones on destroyers were better because they used separate loading ammo - 85lb fixed ammo is not conducive to rapid rates of fire.)

Aside from the machine gun turrets and minus one crew member (which were quickly removed in the A10), you could say the same thing about every Panzer III and IV until 1941 (with less excuse since they had twice the horsepower), and they were still pretty useful...

z42 said:
If you're genuinely surprised by this you must be new here.
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Not new but infrequent visitor. And not particularly surprised but a little disappointed.

I mean this thread was supposed to be about "... just for the RAF and Army; ... What to make at home, what to import, what to export ... while having the realities of technology and budget at the time." And we've ended up in a minor flamewar about the RN (which I've admittedly contributed to, mea culpa).

The "realities ... of budget" mean if you want more of something you will end up with less of something else. But no-one in this discussion seems willing to have less of anything that used a significant amount of resources. It's all just "build the same sort of stuff, but better". Which implies the UK broadly had their priorities right but just fell down on the technical details (as seems almost inevitable with any new tech that is being brought in in a rush and hasn't been tested in combat).

I find that pretty implausible. I think you want to put more significantly more resources into tanks and modernising the Army generally (part of the reason those Covenanters and Crusaders were so crap is that they were rush jobs after R&D was neglected in the beginning of our period). And those resources have to come from somewhere. Either you do Nazi or Communist levels of peacetime mobilisation or you have to cut some other part of the armed services. Same for RAF fighters. (Here is the RAF order of battle in Sep 1939 and here is British aircraft production throughout the war. Few of the real "dogs" were built in large numbers for obvious reasons. If you want to free up significant resources you need to axe planes that seemed "good enough" at the time and actually did some useful work in the war but in hindsight did not bring benefits commensurate with the costs. Like maybe even the Halifax if you believe Bomber Harris.)

Yes maybe you can fix some of this with more efficient organisation (building a government tank design bureau and working closely with Vickers instead of farming design out to totally inexperienced car and railway companies). The US ordnance department actually did a great job of laying the foundations for a mechanically reliable tank family on a tight budget in this period. But $ (or £) are needed as well.

z42 said:
If somehow the UK finds itself with spare capacity in the aero engine industry
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It's not "spare capacity", it's "scarce capacity" and the best use of it. As things worked out yes they would not have been much worse off building nothing but Merlins (though I'd like more Griffons sooner). But the Hercules seemed to go better in certain planes (Beaufighter, Wellington, Halifax) and if the R-2600 can do that job more cheaply why not?

z42 said:
As tends to be mentioned when this is brought up, what aircraft (land or ship based) could do to big gun ships was different in mid war than in the mid 30ies.
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Not sure about that, mid 30s aircraft could carry torpedoes perfectly well. Yes they had to fly slower and lower while dropping them, but then AAA was much less effective so ? And even if so, I thought the whole point was to use hindsight starting in 1936 to make stuff that is more useful mid war?
 
Not quite, the Germans moved away from 14-15mm armor on the "medium" tanks fairly quickly. The MK IVs took a little longer but they had gone to thicker front protection fairly soon.
There were only about 70 MK IIIs with 14-15mm armor and about 40 of them were in the training schools before the Battle for France. 30mm armor is certainly not great but it will protect you from the German 37mm at ranges above 500 meters with standard ammo. 14mm armor won't protect you at 1500 meters. 14mm armor will barely protect you from 7.9mm AP rifle/mg ammo at under 100 meters. 20mm MK II gun was supposed to go through 15mm of armor at 600 meters that was 30 degrees off vertical. Using rifle/mg proof armor on your main battle tank was not a good decision.
The British built about 125 of the A9s. The A 10 was slower but somewhat more survivable. The little turrets looked cute but they were not practical (poor ventilation and vision) and they were expensive. But they built about 175 of the A 10s and that was neither fish nor fowl. 30mm armor was not enough for a 15mph tank. Here is an opportunity (along with canceling a number of the A 11s) to do an early Valentine. Same engine, transmission and track system, smaller hull and thicker armor (even if not up to the full Valentine), loose the hull machine gun. Keep the bigger turret or at least don't go down to the 2 man size.
The early A 13s had the thin armor but they soon fixed it and the powerful engine meant they could up armor existing tanks. The British actually had a pretty good tank in 1938/39.
And then they killed it and screwed up production making several thousand tanks that weren't as good (small cramped turrets with poor vision) even if they ever solved the overheating problem.
That is the basic hardware problem for the British. The other problems like no HE, no improved ammo until 1943, no co-operation with infantry and darn little with the artillery have gone over already. Keep making A 13s with beefed up suspension and 40mm plating on the front until they sort out the Crusader or figure out how to put a bigger turret on the Crusader (taller hull so you can put sponsions out over the tracks to hold the bigger turret ring.)
The Black Swans were nice but they weren't fast enough for some uses. There weren't enough old C class cruisers in good shape ( they were around 20-25 years old) to make very many more AA cruisers. They were also a bit short ranged.
The air threat actually changed a lot from 1935 to 1940. Land based air improved a lot but the threat from aerial torpedoes wasn't that great except for the Japanese. The Germans and the Italians had few torpedoes and this was the standard German torpedo plane for most of the 1930s

By 1940 the British ( a bit more forward thinking) were trying to get the Beaufort into service.
The threat was supposed to level bombers or dive bombers.

You need to cover a lot of threats and that means planning for night combat and for poor weather. You also can't always plan for your opponents to screw up. Turns out the German light cruisers were junk and could not take rough seas. The the Germans got the Blücher sunk and the German high pressure steam power plants sucked and the British subs kept putting torpedoes into the larger German ships and the German navy was down to under 50% by the end of Norway and never really recovered. They caused a lot problems but the poor designs kept them from doing more or fighting the way the British expected. The British may have been planning for a lot more surface commerce raiding where they needed a lot cruisers. Turned out the Germans ships were not good sea keepers, most of them had short range and unreliable machinery.
But you can't plan for that.
 
Shortround6 said:
30mm armor is certainly not great but it will protect you from the German 37mm at ranges above 500 meters with standard ammo.
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Dunno. Even taking 500m for the sake of argument you still have the Germans building medium tanks which are vulnerable to the common threat you identified within the ranges at which the majority of tank combat took place (at least in NW Europe, maybe not Africa).
No argument, basically what I was proposing above (though I was a bit more ambitious with turret ring sizes and guns).

Shortround6 said:
The Black Swans were nice but they weren't fast enough for some uses.
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Yes, that's why I said "You're either protecting capital ships, in which case put the AA guns on the capital ships, or you're protecting merchant convoys, in which case put them on something cheaper..."

On the navy stuff generally, yeah there are reasons they did what they did at the time. But the whole point of this thread is debating with hindsight or how are we going to do any better than they did? And with hindsight we know surface raiders were an order of magnitude smaller threat than U-boats and aircraft (and aircraft were probably a better way of dealing with them in most conditions anyway).

The British are stretched all over the world. Yes the Empire is big on paper but India probably sucks up about as much for internal security as it contributes, and the Dominions don't want to spend anything and don't necessarily take orders. The UK on its own is a smaller economy than Germany, let alone worrying about Japan and Italy. If you build the historical battle fleet and bomber force, you can't use those resources to strengthen your army and fighter force. And as I've argued, stopping France falling in 1940 or even clearing North Africa in 1941 would greatly diminish the strain on the RN. (Holding on to Burma/Malaya in 1942 maybe not so much, but still useful.)

Let's say we're locked into the first 2-3 KGVs given our 1936 start date (and to be fair they actually got into some serious fights during the war). That leaves Anson and Howe which were both laid down in 1937 and commissioned in 1942. "At a cost of £7.5 million the battleship King George V was as expensive to build as a new ordnance or aero-engine factory and, actually, took longer to build." Vs "during World War II a Covenanter tank cost the British Government £12,000, a Crusader tank cost £13,700, a Matilda tank cost £18,000, and a Valentine tank £14,900". So say 500:1? Just going by mass it would be more like 1000:1. Those are the kind of choices you have to make running a war economy. And what exactly did those 2 ships achieve in the war?
 
Shortround6 said:
taller hull so you can put sponsions out over the tracks to hold the bigger turret ring
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Unless you want to go to Sherman heights that might not buy you much. It's not just holding the turret ring it's allowing the gun to recoil while pointed sideways at maximum elevation.
 
Shortround6 said:
They might want to consult with actual navy commanders and coastal fortification officers to find out how well moving ships do against stationary guns. The ships need to outnumber the stationary guns by a large amount.
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One may wish to examine the effects against shipping of the several large coastal guns on either side of the Dover Straits.

Two opposite coasts only about 30km apart with active guns firing at the other side for five years. Apart from shells hitting land targets and towns well inland they also had constant coastal shipping passing in both directions and of both sides. This continued all through that tight funnel at small merchant shipping speeds in all weathers day and night. Naval shipping also passing and small naval vessels up to destroyer size being based nearby.

After all this effort the coastal guns, between both sides very few vessels were ever sunk for the colossal resources put into heavy emplaced coastal guns over a continual campaign for five full years. The last land casualty was Patience Ransley who was in a shelter on the 26th of September 1944 when it was hit by a German 16" shell. The shellings only ceased when British annd Canadian troops overran the Pas de Calais in September 1944.

It does rather suggest that even emplaced heavy coastal guns manned by experienced trained crews have trouble hitting mobile targets that they can see.

Hellfire Corner - British Guild of Tourist Guides

When you start reading about the events of WW2 in the British Isles, you frequently come across photos of the devastating aftermath of the bombing of London. You may also come across many photos from the invasion of Normandy. If Nazi forces could bomb London, which is about 70 miles away from...
britainsbestguides.org
 
Well, a tank with 14-15mm armor is vulnerable at 1500-2000 meters and those green areas for angle shots disappear at the close ranges or turn orange in large arcs. You so called "cheap" 14 ton 6 man tank has a very hard time doing it's job. The 30mm armored tank can get a lot closer or survive taking a few hits while it dishes out a few.
Too much hindsight is unrealistic. Like we KNOW when different radars are going to show up on one side and not the other so we can plan several years ahead of time for the right force mix to take advantage of the technology shifts. Surface raiders were a real problem in 1939/40/ and into 1941. Not all British cruisers had radar even in early 1941 and all the radars were not equal. Without long range search aircraft it raiders could hide for days/weeks. British aircraft had problems with subs in the early years. The British 100lb AS bomb truly sucked and it shouldn't have required hindsight to figure that one out. Bomb was ordered into mass production without ever have been given a live shot test (test bomb detonated with live explosive.) It did more damage to the British aircraft than to German subs.
With more long range search aircraft and with airborne search radar independent surface raiders hand a much, much tougher life.
But using that hindsight to say "well we don't need to build class X, Y and Z ships starting in 1937 because we will have long range aircraft with search radar in 1941/42" makes thing way too easy.
hobbes154 said:
And as I've argued, stopping France falling in 1940 or even clearing North Africa in 1941 would greatly diminish the strain on the RN.
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Well, unless you can fix France or magic up hundreds more British planes, hundreds more tanks (with trained crews) and about double the number of infantry you aren't going to save France.
Clearing NA in 1941 may have been doable.
Like don't go into Greece?
Build more A 13s and kill the Covenanter in it's crib.
Build and issue 2pdr HE ammo.
Send a few hundred more planes (and crews) to NA and figure out ground support tactics/policy even if the fighters just use machine guns or provide decent escort to the bombers.
hobbes154 said:
(Holding on to Burma/Malaya in 1942 maybe not so much, but still useful.)
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Well, if you can clear NA (or pin the Italians/Germans in a small area around Tripoli) so you can at least do some supply by sea to a couple of coastal towns you can free up some resources to send to Malaya/Burma/Indonesia in mid 1941. Japanese were a bit of a bind, If their attack/s in Malaya/Burma/Indonesia didn't succeed quickly they stood a good chance of not succeeding at all. Getting around 100 MK VI light tanks and a few dozen Cruisers would have been a big help as would a few hundred artillery pieces and ammo. Another 6-12 RN subs in the area might have also slowed the Japanese down (another 6-8 transport sunk in the first month?) The Japanese had supply problems. How bad was not known at the time.
hobbes154 said:
during World War II a Covenanter tank cost the British Government £12,000
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And math shows that those useless Covenanter tanks cost the British government 24 million pounds. Enough to pay for 3 KGV battleships with change left over

Yes you do have to make choices. Ordering "new" stuff off the drawing board instead of fixed the things you were making already turned out to be a bad idea more often than not.
For some reason they tended to think that the "new" stuff wasn't going to have development problems.
Didn't matter how good the things on paper looked.
One reason they made so many Hurricanes???
The Typhoon (and Sabre engine) took just over 2 years to get into service after first flight, and it still wasn't right.
 
Shortround6 said:
Well, unless you can fix Franceright.
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Not that difficult in principle. The issue operationally was command and control. Retire the elderly generals etc, build a working real time intelligence system and issue radios all round. Now quick thinking flexible commanders at all levels can see what is happening and issue commands relevant to the actual situation. Not send a man on a motorcycle with a piece of paper to where you last thought your recipient was yesterday with instructions based upon what you thought was happening three days ago.

The French army had many terrible institutional weaknesses but the troops and more junior officers put up a brave and hard fight on the ground which was wasted by their higher command.

Of course one can spend days listing the detail changes down to greatcoats and belt buckles but command and control are the room's elephant. Alongside the great French national sport of politics of course.
 
On a more nuts and bolts level the French didn't have enough radios, having tanks with brackets/shelves already in the tanks but no radios doesn't work. The radios they had often were not very good (very short ranged) so command and control problems extended down into company and platoon level.

Getting back to the British, most of the British armor arrived too late, was not fully equipped, some tanks were fitting their machine guns on the French quaysides after unloading.
Not enough radios and not enough spare parts to fix any that weren't working right. And instead of heading for a French training camp to sort everything out for a few weeks, they were sent right into battle and piecemeal at that. They had also been separated from their infantry and artillery and were supposed to beef up French units which they only communicate using voice in person and pretty much school boy French for the British or schoolboy English for the French officers.
One British unit had an A 9 CS with no ammo of any sort for the 3.7 and not enough for the machine guns. They used it as a command tank for the MK VI light tanks.
 

If the success rate for coastal artillery was this bad, how come ships ever managed to hit each other then? Surely hitting a moving target from a moving platform is even harder than hitting a moving target from a fixed platform? If the answer is that big gun ships had better fire control, then why didn't they add better fire control to the shore batteries?
 
In hindsight the Anglo-French may have been slightly better off using 1st Armoured Division later after it got some training and the proper supplies. The timing and location were obviously not there to salvage the trapped forces in the North, but a notable issue for the battle of the Somme in early June was the very limited armoured reserves.
Both 1st Armoured and the French lost substantial armored forces launching piecemeal attacks on the Abbeville area.

The impact is not negligible as an extended Somme campaign can make the difference between what happened and the French being able to retreat to a more prepared 2nd line (Loire-front of Paris) as intended and to bring more completed units to bear, enough to make the Battle of France substantially longer and costlier for the Germans.

In practice 1st Armoured was rather wasted.
 
In practice ships at sea of all sizes didn't do any better. The ammunition expenditure v the relatively few number of hits obtained throughout WW2 by all navies is staggering. Some data here.

It was something that was commented on by the Admiralty at various times all the way through to the final actions in the IO in the summer of 1945.
 
Just spent a bunch of time down the rabbit hole there. Great stuff!
 
The RN Gunnery Pocket Book 1945 edition explains what is needed to overcome the "Fire Control Problem" in Chapter VII Section 2, including a diagram of a typical Admiralty Fire Control Table.

Photo of the AFCT fitted to HMS Belfast

View: https://www.flickr.com/photos/67307569@N00/5428820838/in/photostream/lightbox/

Often not recognised is the length of time a shell can be in the air, from point of leaving the barrel to impact, whether it is a hit or miss.

The pair of 15" Mk.I guns in coastal mounts at the Wanstone Battery at Dover (nicknamed Clem & Jane) could, with supercharges, range out to 42,000 yards at 44.6° elevation and reaching a maximum ordinate of 36,800ft. The shell was airborne for 95.5 seconds. Even at 30.3° a range of 36,500 yards was achievable with a flight time of 69.2 seconds. In this case the maximum ordinate was 19,330 ft. Using standard charges at 30.5° at out to 32,500 yards still gives a flight time of 65.41 seconds with a maximum ordinate of 17,340ft.

So figure in climactic conditions (gusts of wind), an enemy who might change course, etc, it is small wonder that with only two such guns in the battery, few hits would be achieved.

Details of the Dover guns can be found here.

Dover Strait coastal guns - Wikipedia

en.wikipedia.org
 
So much more than an "informative".
Great post.
 
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