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G3 Battle Cruiser and N3 Battleship

Grey Havoc

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A postcard which I discovered in my files recently. It shows an exhibit in the Crystal Palace in London, probably during the Great War Exhibition of 1920. The photo’s title is:

REPLICA OF THE WORLD’S BIGGEST GUN, ITS PROJECTILES AND CHARGE

The four projectiles shown are stencilled as follows (from left to right):
18 IN MK 1A A.P.C. FUZED
18 IN MK 1A H.E. FUZED
18 IN MK 1A SHRAPNEL FUZED
18 IN MK 1A C.P.C. FUZED

The topmost of the six propellant charges stacked up is labelled: 18 IN BL 105 LB CORDITE MD SIZE 45 1/6 CHARGE

A comparison with other gun photos, plus the six charges (which represent the full charge: 6 x 105 lb = 630 lb total charge) confirm that this replica is of the 18 inch naval gun which saw RN service in WW1, not the later, less powerful, howitzer. The shrapnel shell was presumably developed for its ultimate purpose of shore bombardment. The shells weighed in at 3,320 lbs (1506 kg).

More details about the gun and its ammunition are here: http://www.navweaps.com/Weapons/WNBR_18-40_mk1.php

View attachment 616245
 

Bruno Anthony

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G3/N3 fantasy ships. Roughly same dimensions as Yamato and Iowa but in case of N3 resistant to 18” fire but with the displacement of Iowa?????
BULLS#$&!
 

1Big Rich

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The 2 best ships Britain never built.
Woody echoes John Roberts:

Of all the capital ships that were designed for the Royal Navy, those which, without doubt, would have been regarded as the best were never built. --John Roberts
Regarding F2 and F3, when I took over the BC board from the late Bob Hennneman,, I added an "Own Designs" board since we lost a rather fruitful one with the destruction of Warship Projects 3.0. I posted Red Admiral's drawing there, but Smurf revealed he had images of actual sketches of what F2 and F3 would have looked like. I added those to that thread, along with is commentary. Those can be seen here:

https://www.tapatalk.com/groups/alltheworldsbattlecruisers/f2-and-f3-battlecruisers-t8627.html

Great work by Red Admiral providing lists and images of of the speculative RN designs of the era, and great commentary by Smurf.

Regards,
 

Hood

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G3/N3 fantasy ships. Roughly same dimensions as Yamato and Iowa but in case of N3 resistant to 18” fire but with the displacement of Iowa?????
BULLS#$&!
The highly experienced DNC d'Enycourt (who had been designing battleships for two decades) and his team did not go in for BS, they spent two years of innovative design work on these designs.

The Iowa's had much thinner armour than the these designs.
N3 had a 15in thick belt inclined at 18 degrees over the magazines which tapered to 13.5in over the machinery spaces and a 14-9in forward and 14-6in aft bulkheads. The deck armour was 8in on the upper deck, 8in on the lower deck forward, with 8in and 6in aft.
G3 originally had a 14in thick belt inclined at 25 degrees and 8 to 9in thick deck armour. This was scaled back to a 14in thick belt inclined at 18 degrees, bulkheads as N3. The deck armour was 4in over machinery, 8in on flat and 9in on slope over the main magazines and as far aft as the middle boiler room, 7in over the 6in magazines and the after engine room.

Iowa's armour was designed to give a zone of immunity against fire from 16in shells between 18,000 and 30,000yds. Admittedly she had later steels such as STS in her armour scheme - but this was used to save weight. The magazines and engine rooms were protected by a 1.5in STS outer hull plating and 12.1in thick belt on a 0.875in STS backing plate, sloped at 19 degrees (equivalent to a vertical 17in plate) (439 mm), the fore and aft bulkheads were 11.3in (thickened to 14.5in on Missouri and Wisconsin. Deck armour was a 1.5in STS weather deck, 6in armoured deck and a 0.63in STS splinter deck, which over the magazines was 1in. The barbettes were thicker though than the earlier British designs by at least 2in.

Now, what do we mean proof to 18in shells?
The 40cm/45 Type 94 could penetrate a 19.4-22.2in thick belt or 6.5-4.3in of deck armour at 21,872yd (depending on sources), reducing to 14.1-16.3in and 7.4-9.6in respectively at 32,808yd (the gun's range was 35,600yd).

When the N3 was designed, the the requirement for its 18in/45 Mk.II guns was to be capable of defeating a ship protected by a 15in belt and a 7in-inch deck. That was the requirement that led to the selection of an 18in gun and so the ships were armoured to withstand the same. The requirements pretty much meet the same ballpark as the performance achieved by the Type 94 gun - although the British Mk.II had a longer range (42,000yd). So I think based on this data the N3 and G3 would prove to be better able to withstand Yamato's shells, but they were designed to do that - the Iowa was designed to counter other 16in armed ships and although her armour was excellent, it wasn't really designed to defeat such shells - at the time she was designed nobody thought such guns were afloat so its no surprise there was a limit.

As to displacement - Iowa put a lot of her tonnage into her propulsion compared to N3. The G3 was ambitious, but both had novel design layouts with clustered turrets and aft machinery to make the most of the armour and concentrate its weight over smaller areas. The G3s would never of reached 32kt even in trial condition, but they would still have been faster than anything comparable.
 

Tzoli

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Note that Iowa's armour was immunity against not the Mark 7 Cannons but the previous Mark 6 eg a slower cannon. Montana would had truly the immunity against own shells.
 

Bruno Anthony

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G3/N3 fantasy ships. Roughly same dimensions as Yamato and Iowa but in case of N3 resistant to 18” fire but with the displacement of Iowa?????
BULLS#$&!
Note sure if you are trolling or just simply ignorant on this matter....
Taking G3 & Iowa:
2 ships w/similar speeds and dimensions (Iowa w/higher pressure boilers) yet G3 has heavier armor? Were some places thinned due to grouping of turrets?
N3/Montana:
N3 significantly lighter ship but w/armor for 2900lb shellfire while Montana armored for 16”50 2700lb shell?
 

Tzoli

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you do know that there are 20 years between G3 and N3 representing full WW1 experience and Iowa / Montana representing the requirement for higher speed and protection against AA attack? (Both by guns and armour)

As for weapons:
16"/50 Mark 7
1224,7kg shell at 762m/s MV

18"/45 Mark II
1323kg at 808m/s MV

As you can see the Mark II 18" cannon is superior to the 16"/50 and the 16" already using the super heavy shell, while the RN only developing considering such shells during mid late WW2.

N3 was lighter because it it was slower and had shorter range while Montana was both faster and longer ranged.
I think Armament weight was quite close the two ships.
 

Bruno Anthony

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I have some weight figures for N3:
N3 weights from Friedman: as of 17 June 1921

LOA: 825’
Beam: 106’

Weights:

Hull:17,900
Machinery:2720
Armament:8850
Equipment:1000
Protection:16,700
Oil:1100
Margin:230

Normal: 48,500 tons

Belt: 15”
Deck: 8”-7”
 

Bruno Anthony

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G3:
G3 weight breakdown:

Hull: 17,860 tons
Machinery: 6000 tons
Armament: 7030 tons
Equipment: 1000 tons
Protection: 14,700 tons
Oil: 1200 tons
Margin: 210 tons

Normal displacement: 48,000 tons
 

Tzoli

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N3 armour:
uniform 203mm deck all over magazines and machinery,
381mm belt over magazines and 343mm over machinery

G3 armour: (The 16,5" version)
203mm deck over magazines and 51mm over machinery,
uniform 305mm belt over magazines and machinery,
also 229mm slopes over magazines and 76mm over machinery

G3 armour (The final 16" version)
203mm deck over magazines and 102mm over machinery,
356mm belt over magazines and 305mm over machinery,
no slope armour

And a sidenote:
N3 was still in development when the WNT halted/cancelled/redistributed their development as there was a variant with 4x3 16" rather 3x3 18"
 

JFC Fuller

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The highly experienced DNC d'Enycourt (who had been designing battleships for two decades) and his team did not go in for BS, they spent two years of innovative design work on these designs.
And that innovation went into the detail design too, there was to be electric welding of the deck armour and possibly other parts of the ship, and there was the ordering of multiple prototype 18" guns to identify the most suitable construction method. Many of the chosen features, turreted secondaries and the tower superstructure, were the direct product of post-war lessons learned committees. I would argue that the 1919-22 period represents one of the periods of greatest innovation in RN ship design of the entire big-gun era.

It is a nonsensical idea as the ships were so closely mapped to RN understanding of the South Dakota's and Lexingtons but I have always wondered what could have been achieved with a "fusion" design; 18" guns and 25-28 knot speed. Perhaps weight could be saved by having an 3-2-3 eight gun main armament arrangement sufficient to provide 80-90,000SHP? perhaps with some armour thinning or adjustments to the machinery layout?
 

Bruno Anthony

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N3 armour:
uniform 203mm deck all over magazines and machinery,
381mm belt over magazines and 343mm over machinery

G3 armour: (The 16,5" version)
203mm deck over magazines and 51mm over machinery,
uniform 305mm belt over magazines and machinery,
also 229mm slopes over magazines and 76mm over machinery

G3 armour (The final 16" version)
203mm deck over magazines and 102mm over machinery,
356mm belt over magazines and 305mm over machinery,
no slope armour

And a sidenote:
N3 was still in development when the WNT halted/cancelled/redistributed their development as there was a variant with 4x3 16" rather 3x3 18"
For non metric types:
N3
8” deck
15” -13.5” belt

G3
8”-4” deck
14”-12” belt

Any info on citadel length?
 

1Big Rich

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If you like battlewagons this excellent company has all of them in metal to 1/1250 scale.
Thanks for that uk 75.

Alnavco has a Superior F3 in 1/1200, closer to Red Admiral's drawing than the historic sketches Smurf provided.



online ordering is down at their site


But models can still be ordered via phone or email (or snail mail)

Regards,
 

Foo Fighter

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Not being a naval historian I have always wondered, why have the turrets for MA up front? In my mind it cuts your firepower in half unless the target is in front of you. Simplistic perhaps but why?
 

Nick Sumner

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Not being a naval historian I have always wondered, why have the turrets for MA up front? In my mind it cuts your firepower in half unless the target is in front of you. Simplistic perhaps but why?
Shorter armour belt is possible with a moulded hull. magazines tend to be towards the ends of a ship where the hull lines are narrowing meaning a longer length of heavy vertical armour is required to protect them. Nelson mags are close to the centre of the ship so fullest hull lines = shortest armour belt. Added bonus - also giving space for a deeper TDS. Americans got round it with SoDak II and Iowa by having a straight sided hull. Lots of hydrodynamic tank work showed that if you got the hull lines 'just so' you didn't have to have too much taper at bow and stern to also have a hydrodynamically efficient hull shape.
 

Tzoli

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One Word: Jutland

More words:
Jutland and the battles of Heligoland Bight showed that end on fire was much less important then before (even by the construction of the Orion class) and future battles will be fought as broadside battles. For such it isn't important how many turrets could face forward as only a few shots could be fired before the ships would turn to bear all the guns on the enemy.
Also putting like 2.000tons of rotating mass 10m (3rd turret superfiring above the 2nd) above the deck would put a serious strain on the hull and would require a deep hull to stabilise it which would increase the ship size and mostly cost.
 

Foo Fighter

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Not being a naval historian I have always wondered, why have the turrets for MA up front? In my mind it cuts your firepower in half unless the target is in front of you. Simplistic perhaps but why?
Shorter armour belt is possible with a moulded hull. magazines tend to be towards the ends of a ship where the hull lines are narrowing meaning a longer length of heavy vertical armour is required to protect them. Nelson mags are close to the centre of the ship so fullest hull lines = shortest armour belt. Added bonus - also giving space for a deeper TDS. Americans got round it with SoDak II and Iowa by having a straight sided hull. Lots of hydrodynamic tank work showed that if you got the hull lines 'just so' you didn't have to have too much taper at bow and stern to also have a hydrodynamically efficient hull shape.
Thanks very much, I shall consider myself edjumified.
 

Volkodav

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The other factor was protection of the aft magazine from head on plunging shell fire. The concern was uptakes from the boilers could not be armoured hence plunging shell fire from the forward arc could pass through the uptake deck penetrations and bulkheads forward of the magazine and detonate it. By moving the turret forward this weak point was avoided offering greater protection over all as the ship closed with the enemy.
 

able

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RN small battleship and big cruiser all with 14" turrets . Five KGV should be replaced by 4+6

SP1050780.JPG
 

Volkodav

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RN small battleship and big cruiser all with 14" turrets . Five KGV should be replaced by 4+6

View attachment 634640
Nice, I have a Nelson to complete in a similar manner, a notional mid 30s 2x quad 14" battlecruiser, superstructure moved forward and larger machinery space.
 

Colonial-Marine

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If the layout used by the Nelson class offered so many advantages why the unusual layout of the G3 and N3 which put X turret between the fore and aft superstructure? What did this offer over having all three turrets forward?

Nelson, G3, N3, all had thick belts but weren't they somewhat vulnerable to hits beneath the belt? When they were designed was the possibility of hits well below the waterline less likely? The Iowa and South Dakota only had a 12.2" Class A main belt but they had a tapered extension underneath which must have cost some weight that otherwise could have gone into main belt thickness.
 

Sherman Tank

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You've got it the wrong way around. The Nelson layout was forced on the design because it was a scaled-down G3. Packing all nine 16-inchers so close together caused problems with blast effect on the bridge and on their internal structure.
 

Antonio

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Magnificent was a real design?
 
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