Design Bureau Guangzhou

Started by Logi, December 29, 2009, 03:41:55 PM

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snip

when I heard Fuso with quads, thats the fist thing that poped into my head
You smug-faced crowds with kindling eye
Who cheer when solider lads march by
Sneak home and pray that you'll never know
The hell where youth and laughter go.
-Siegfried Sassoon

Guinness

If anything I think the turrets, especially the roofs are overarmored, and the main belt is too short for a 23 knot, 720 foot long ship. It's ironic that a ship meant to soft-kill the enemy would present so small an armored area to the enemy. The logic of it seems internally consistent at least (designed to soft-kill an enemy armed with larger guns shooting AP rounds and all).

But what happens when it meets a 16" armed opponent with similar speed? Couldn't such a ship stay out of effective range of all those 14" guns and rain down AP shells at steep angles, defeating the relatively thin armored deck? It seems that if that's the case, this ship would never get close enough to execute it's strategy.

Also, having now anti-tb defense at all is a questionable strategy for a ship operating near so many TB happy foes and potential foes. One would hope it has lots of capable escorts. Recent battles have shown the importance of capital ship mounted anti-TB weapons for "last ditch" defense against determined torpedo attack (at least IMHO).

Logi

#182
QuoteIf anything I think the turrets, especially the roofs are overarmored, and the main belt is too short for a 23 knot, 720 foot long ship. It's ironic that a ship meant to soft-kill the enemy would present so small an armored area to the enemy. The logic of it seems internally consistent at least (designed to soft-kill an enemy armed with larger guns shooting AP rounds and all).

Actually, by my calculations, the face armor outperforms the main belt by maybe 1000~2000 yds of immunity. The roof is impenetrable at any distance of course. However, as I said, 40kt capped ships make hard compromises.

Here this ship offers a higher chance of being hit in an unarmored area in return for 3 x the chance to do so on the enemy. 24 guns vs 8 guns for a short main belt.

Oh and btw, this ship is designed AoN style so that even if the outer area is riddled with holes, it can still float. You notice it says main belt is 107% of normal length.

QuoteBut what happens when it meets a 16" armed opponent with similar speed? Couldn't such a ship stay out of effective range of all those 14" guns and rain down AP shells at steep angles, defeating the relatively thin armored deck? It seems that if that's the case, this ship would never get close enough to execute it's strategy.

Would be if not considering the state of current 16" guns. Let's use the 16"/40 carrying a 960kg shell used by Orange.

Immunity Zone of the belt and deck is 10,000 yds - 18,500 yds.
Immunity Zone of the belt and deck to the 14"/45 Superheavy is: 10,430 yds - 20,360 yds.

The immunity zone against the 14"/45 is roughly 2300 yds larger than the 16"/40. That's actually not a whole lot.

As you noted, staying out of the effective range could most certainly be done, but the key word is EFFECTIVE. As the RRC noted, it's pretty much NOT effective at all ranges for large caliber weapons due to the thickness of armor and the similarly of how much armor ships have. It's simply not worth the addition weight for the very low gains in protection.

However, not all portions of the ship is immune, thus you fire at those areas to cause a soft kill. In fact, you don't have to close in to do this. That is, it doesn't have to the close the range at all and can fire any ANY range because either ways, somethings will not going to be protected against a 14" APC shell going at a steep angle.

The point is not to close the distance, but to soft kill a ship at any distance. Precisely because it's soft killing, not attempting to penetrate.

QuoteAlso, having now anti-tb defense at all is a questionable strategy for a ship operating near so many TB happy foes and potential foes. One would hope it has lots of capable escorts. Recent battles have shown the importance of capital ship mounted anti-TB weapons for "last ditch" defense against determined torpedo attack (at least IMHO).

As I said, having a secondary would interfere with the main batteries firing arcs and that it couldn't be carried without breaking the 40kt limit anyways. Thus the ship has to operate with escorts. But if you're pitting this ship on a solo mission, you should expect it to be sunk anyways. No amount of secondaries will prevent a torpedo kill from a determined enemy.


Note* By Immunity Zone I mean Proof from the gun. Partially penetrated is a different number by far.

Logi

#183
Quick sketch of the placement for everything.


Scale: 1 pixel = 1 ft

Blue Box is a turret (40 ft diameter for 14" quads), Gun is Gun Barrels (I used 40 ft out of the barrel, should really be 30-35 ft).

Yellow lines denote the superstructure area (for forward and aft bridge), I presume a thin level of super-structure under the two center guns.

Red denotes the armored box area.

Black denotes the center-line, the forecastle limit, and the quarterdeck limit.

As you can see at most, the forecastle limit is crossed. Adjust to 15% forecastle and we are fine. As the deck in this portion is flush, this takes/adds no composite strength, thus I will not post the SS with 15% forecastle.

Carthaginian

Would it work?
By all means.

Could you build it?
By all means!

Can I sink it with 1/4 the tonnage in destroyers in a coordinated attack?
BY ALL MEANS!!!

By the time that I tied up the escorting vessels in a conventional naval battle, this monster would suddenly be staring down the barrel of about 90 torpedoes aimed for it. It has no way to defend itself from small, fast-moving attackers that manage to get in under it's escort cover. So, if you want a white elephant for national pride that will only ensure that the MK will wint he war... build away.
So 'ere's to you, Fuzzy-Wuzzy, at your 'ome in old Baghdad;
You're a pore benighted 'eathen but a first-class fightin' man;
We gives you your certificate, an' if you want it signed
We'll come an' 'ave a romp with you whenever you're inclined.

Logi

#185
When did you ever get the impression I was actually building this ships?

You do realize, I have about twenty different large ship designs posted but all I've been building are 200t TBs.

QuoteCan I sink it with 1/4 the tonnage in destroyers in a coordinated attack?
BY ALL MEANS!!!

CT made a elaborate explanation on this, if there is a sizable escort, which there should be, you will need maybe 70 destroyers. Sure, less tonnage, but building them in a useful time is a different matter. Not to mention the sudden bad press lost and the numbers of sailors dead.

To put it in a better way. Say I have three Chongqing's as escort. They all have 12 6" guns at a broadside. Say they begin firing at max FC range, 18,000 yds.

Say the Destroyers are now making full steam towards the ships at 32 kts. Say 2 6" shell will disable/sink a destroyer. Each shell has something of a 1/20 chance to land.

The RoF for the 6"/50 is about 6 rounds/min. The Destroyers cover ~1080 yds per minute. Destroyers released torpedoes at 8000 yds.

So we have a volley of 36 6" shells, 2 hits to sink, and a time of 9.26 minutes to close to torpedo distance.

So in that time, 2000 6" have flown. Chances are 100 have hit. So we have 50 destroyers sunk or disabled without releasing torpedoes.

And DDs that can take 2 6" shells before sinking are usually 750 tons or above. So you lost 37,500 tons of destroyers in just one rush (going by the minimal tonnage of 750ton DDs).

--------

China's cruisers are not the conventional cruisers, they are not cruiser fighters, they are torpedo-boat and destroyer sinkers. They were never meant to perform anti-cruiser duty. Hence they have an extremely high number of barrels, not to fight cruisers, but to kill the swarm.

So a fleet makeup would look something like this:

2 Huge BB
6 CL (TB/DD Killer)
12 Boomsticks (DDs that kill Cruisers)

In other words,Those DDs, (the ones with 6"/52 gun which is extremely unsuited for anti-TB/DD work due to RoF) will be the ones sinking your cruisers. The Cruisers wouldn't be tied up.

As for the Boomstick effectiveness...

Each 6"/52 shell can penetrate anything short of, I think 2" deck? And then you have 4 guns on each DDs carrying that. Sure the DDs are easy to sink, but to fight a 12kt Cruiser, I have 12 DDs. So volume of fire is maybe 8 x 8" vs 48 x 6" shells.

RoF means in a minute, 8-16 8" shells in a min, 192-240 6" shells in a min.

In terms of Broadside weight: that's 2080lb-4160lb of 8" shells vs. 24,576lb-30,720lb of 6" shells.

Ouch.

Carthaginian

#186
Quote from: Logi on August 26, 2010, 04:30:48 PM
When did you ever get the impression I was actually building this ships?

You do realize, I have about twenty different large ship designs posted but all I've been building are 200t TBs.

QuoteCan I sink it with 1/4 the tonnage in destroyers in a coordinated attack?
BY ALL MEANS!!!

CT made a elaborate explanation on this, if there is a sizable escort, which there should be, you will need maybe 70 destroyers. Sure, less tonnage, but building them in a useful time is a different matter. Not to mention the sudden bad press lost and the numbers of sailors dead.

I know you're building TB's... I was just pointing out the difference between 'cool big ship' and 'practical big ship.
I'll even play along with your example to illustrate my point.

OK, I send in my 10,000 tons worth of destroyers, plus THEIR escorts, against your monster and it's escorts.
Let's say that I send in an equal tonnage of ships- albeit distributed a bit differently:
3 Hatchitigbee's to make your escorts miserable - 15,000 tons
5 El Paso's to escort my destroyers to the target - 22,250 tons
10 TR-235's to actually go in and torpedo the BB - 10,000 tons

My total strike force has been assembled for only a bit more tonnage than your battleship.

So, now you have twenty-one 14" guns to fire on me... if you see me.
Whether you see me before I see you- or if we see each other outside of 5.5"-6" gun range at all- is a moot point.
By the time range closes, you have 4 ships firing on 18... not good odds at all, even if one of them is your monster. Your escorts are NOT getting target-practice quality shots off due to the fact that they are dancing, trying to get away from the ships that are shooting at them, and totally ignoring the BB except for standard evasive movement. Your escorts can be damaged by any one of my ships all things being equal, and are trying not to get hit by them just as hard as I'm trying not to get hit by you. So, your 4 ships that can fore on (most likely) only 4 targets at once are now under attack by 8 ships, all of them armored as well or better than 3 of your ships.

Again... not great odds.

While your forces are trying to take out my escorting ships, the DD's bore in for the kill.
Say I loose half- that's still 5 ships with 6 torps each still making torpedo range... 30 torps are launched from 8000 yards.

So, whatever happens to our escorts- they aren't the subject- you still think that my strike force would fare so poorly as in your lop-sided example? Especially if I'm sending in a well-balanced escort of my own, in addition to my 10,000 tons of destroyers?

Especially if I throw in a BB or two of my own to 'escort' my destroyers?
Say, roughly equal in tonnage to your escorts?
So 'ere's to you, Fuzzy-Wuzzy, at your 'ome in old Baghdad;
You're a pore benighted 'eathen but a first-class fightin' man;
We gives you your certificate, an' if you want it signed
We'll come an' 'ave a romp with you whenever you're inclined.

Logi

QuoteSo, now you have twenty-one 14" guns to fire on me... if you see me.
No I do not see.

QuoteBy the time range closes, you have 4 ships firing on 18... not good odds at all, even if one of them is your monster.
Say how?

QuoteYour escorts are NOT getting target-practice quality shots off due to the fact that they are dancing, trying to get away from the ships that are shooting at them, and totally ignoring the BB except for standard evasive movement.
Your ships should be dancing around from Boomstick shots. Nothing is immune save the BB and the BB should be occupied by the monster BB.

QuoteYour escorts can be damaged by any one of my ships all things being equal, and are trying not to get hit by them just as hard as I'm trying not to get hit by you.
And your escorts shooting my cruisers got swiss-cheesed with holes by the Boomsticks.

QuoteYour escorts can be damaged by any one of my ships all things being equal, and are trying not to get hit by them just as hard as I'm trying not to get hit by you.

If I had the equal tonnage to use, you expect for ever 1kt your ships have, 1 Boomstick is there to fire. And yields a higher RoF and Broadside weight per min than your ships do, ton for ton.

QuoteSo, your 4 ships that can fore on (most likely) only 4 targets at once are now under attack by 8 ships, all of them armored as well or better than 3 of your ships.
As I noted, at this stage, armored a bit better doesn't really do anything. For immunity from the Boomsticks your large ships need BB style Deck armor. Which I doubt they have.

Logi

#188
Let's make this scenario then:

Say you had two Tennesse class ships (30.3 kt each)
3 Hatchitigbee's to make your escorts miserable - 18,000 tons (6kt each x 3 is 18 kt, not 15 kt)
5 El Paso's to escort my destroyers to the target - 22,250 tons (can't find this one, think 4,450 t each)
10 TR-235's to actually go in and torpedo the BB - 10,000 tons (1 kt each)
Total: 110.85 kt

Say I have 1 Fusop Wannabe (40 kt)
6 Chongqing - 36,000 tons (6kt each)
34 Boomsticks - 34,000 tons (1 kt each)
Total: 110 kt

Engagement: Your two BBs were be occupied with my Fuso-Wannabe as is mine.

Your three Hatchchitigbees and 5 El Paso will be engaged with my 34 Boomsticks.

That's 3 x (5 x 7.5" gun) + 5 x (4 x 4.5" gun) vs. 34 x (4 x 6" gun).

RoF of 7.5" I will assume an optimistic 2 rounds/min.
Rof of the 4.5" I will assume 6 rounds/min.

Rof of 6" is a lower 4 round/min.

That means in the Escorts Vs. Boomstick battle, 30 x 7.5" shell + 120 x 4.5" shell VS. 544 x 6" shell per minute.

That makes broadside weight of 1 minute: 12,000lbs VS. 69,632 lbs.

Oh, and your escorts do not have the armor to protect against the 6" are any useful range.

Needless to say 2000 6" shells from the Chongqing will fly before the TR-235 can close the distance and that means 100 shells will land. By survivability, each TR-235 can last 2.5 shells, meaning every three shells they sink.

I have enough escort fire to sink the TR-235s 3 times over.

Ultimately the screen is very sound, what isn't is the chance that the Fuso-wannabe might be out matched and lose to the two Tennessee.

Jefgte

Quote...To put it in a better way. Say I have three Chongqing's as escort. They all have 12 6" guns at a broadside. Say they begin firing at max FC range, 18,000 yds.

Say the Destroyers are now making full steam towards the ships at 32 kts. Say 2 6" shell will disable/sink a destroyer. Each shell has something of a 1/20 chance to land.

The RoF for the 6"/50 is about 6 rounds/min. The Destroyers cover ~1080 yds per minute. Destroyers released torpedoes at 8000 yds.

So we have a volley of 36 6" shells, 2 hits to sink, and a time of 9.26 minutes to close to torpedo distance.

So in that time, 2000 6" have flown. Chances are 100 have hit. So we have 50 destroyers sunk or disabled without releasing torpedoes.

And DDs that can take 2 6" shells before sinking are usually 750 tons or above. So you lost 37,500 tons of destroyers in just one rush (going by the minimal tonnage of 750ton DDs).

...

I like your calculation


Jef
"You French are fighting for money, while we English are fighting for honor!"
"Everyone is fighting for what they miss. "
Surcouf

Logi

This is just my adaption of CT's calculations for why the Swiss should have made off with much fewer kills and many more loses during their destroyer/torpedo-boat raid of the Allied forces.

Takes a lot to make a destroyer charge effective.

Jefgte

Quote...Takes a lot to make a destroyer charge effective....

Takes a lot to repulse them...


Jef  ;)
"You French are fighting for money, while we English are fighting for honor!"
"Everyone is fighting for what they miss. "
Surcouf

Logi

#192
True, but you think a navy geared specifically towards repulsing swarms would know how to. Not every nation's naval policy has been, defeat the swarm, for years.

Also Destroyers charges have never ended well unless under good circumstances. Meaning visibility is heavily obscured, the enemy is heavily suppressed by supporting fire, etc. Which, in this case, couldn't be done.

Besides, my example is a Fuso-Wannabe not moving parallel to the enemy ships. If it would moving back at an angle which still allows fire, it would extend the distance and time needed to close in quite some. Giving in more chances to sink the destroyer rush.

Logi

#193
Let's say the Fuso* is doing a 45 degrees retreat, this still allows firing from the Fuso*.

The distance gained by such going at 23 kts (if we assume that the Fuso* simply goes down in direction, and do not count added distance to to it being horizontal as well)

then the Fuso* is making ~16.26 knots in the downward vector.

That means the Destroyers are only gaining (still by trial speed, they are going 32.5 knots) only 16.24 knots.

That means they are covering 548.64 yards every minute.

Assuming they started their charge at 18,000 yards and I didn't fire until 18,000 yds, they have 18.23 minutes to close the distance to effective torpedo range (8,000 yds) under fire.

Almost double the time needed to close in due to my 45 degrees angling, giving time for my escorts to launch 3924 6" shells into the air.

Again, three hits to sinks and 1/20 a chance to hit, 65.4 TR-235 sunk.



As for escorts and what-not. A Fleet consisting of Fuso*, Chongqings is not complete as it lacks firepower vs escort ships. That means Boomsticks.

You highlighted a good point in your original post, my cruisers were sunk or pinned. But that was precisely because they weren't made to engage those enemies. That is the Boomstick's job. Indeed, take one element of the defense out and the whole task force collapses.

Logi

That 7000t Pocket BB (Monitor) that Jeftge pointed out interested me, so here is my version of it.

The 9" Belt @ 20 degrees sits 12' tall and makes it pretty hard to penetrate. Tough nut to crack.

QuoteLurdan, RRC Pocket Battleship laid down 1919 (Engine 1916)

Displacement:
   7,000 t light; 7,354 t standard; 8,046 t normal; 8,599 t full load

Dimensions: Length overall / water x beam x draught
   393.70 ft / 393.70 ft x 65.00 ft x 21.00 ft (normal load)
   120.00 m / 120.00 m x 19.81 m  x 6.40 m

Armament:
      6 - 11.00" / 279 mm guns (2x3 guns), 665.50lbs / 301.87kg shells, 1919 Model
     Breech loading guns in turrets (on barbettes)
     on centreline ends, evenly spread
      8 - 4.13" / 105 mm guns (4x2 guns), 35.32lbs / 16.02kg shells, 1919 Model
     Quick firing guns in deck mounts with hoists
     on side, all amidships
   Weight of broadside 4,276 lbs / 1,939 kg
   Shells per gun, main battery: 80
   6 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   9.00" / 229 mm   255.00 ft / 77.72 m   13.14 ft / 4.01 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   11.0" / 279 mm   2.00" / 51 mm      4.00" / 102 mm

   - Armour deck: 1.50" / 38 mm, Conning tower: 4.00" / 102 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 4 shafts, 20,813 shp / 15,527 Kw = 22.00 kts
   Range 8,000nm at 12.00 kts
   Bunker at max displacement = 1,245 tons

Complement:
   424 - 552

Cost:
   £1.751 million / $7.004 million

Distribution of weights at normal displacement:
   Armament: 534 tons, 6.6 %
   Armour: 2,192 tons, 27.2 %
      - Belts: 1,321 tons, 16.4 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 353 tons, 4.4 %
      - Armour Deck: 484 tons, 6.0 %
      - Conning Tower: 35 tons, 0.4 %
   Machinery: 775 tons, 9.6 %
   Hull, fittings & equipment: 3,155 tons, 39.2 %
   Fuel, ammunition & stores: 1,046 tons, 13.0 %
   Miscellaneous weights: 343 tons, 4.3 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     8,858 lbs / 4,018 Kg = 13.3 x 11.0 " / 279 mm shells or 1.7 torpedoes
   Stability (Unstable if below 1.00): 1.09
   Metacentric height 3.1 ft / 0.9 m
   Roll period: 15.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 58 %
         - Recoil effect (Restricted arc if above 1.00): 0.61
   Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.524
   Length to Beam Ratio: 6.06 : 1
   'Natural speed' for length: 19.84 kts
   Power going to wave formation at top speed: 55 %
   Trim (Max stability = 0, Max steadiness = 100): 57
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      13.00 ft / 3.96 m
      - Forecastle (20 %):   13.00 ft / 3.96 m
      - Mid (50 %):      13.00 ft / 3.96 m
      - Quarterdeck (15 %):   13.00 ft / 3.96 m
      - Stern:      13.00 ft / 3.96 m
      - Average freeboard:   13.00 ft / 3.96 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 85.2 %
      - Above water (accommodation/working, high = better): 85.4 %
   Waterplane Area: 17,431 Square feet or 1,619 Square metres
   Displacement factor (Displacement / loading): 96 %
   Structure weight / hull surface area: 128 lbs/sq ft or 626 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.92
      - Longitudinal: 2.09
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is cramped