WesWorld

Btw, I had my own share of thoughts about BCV. ;o)

Just look here and scroll down.

Quoted

If you have a sketch, please post. Makes discussions much easier.

I usually make a sketch for Scheme 1 of the ship (if it is much different from the norm) and not for the subsequent 1A2, 1A3 etc.
The sketch I have on hand is on paper (alas!) and was for the initial number crunching. As such the hull form is not necessarily indicative of the Scheme 5 SS file you see. But I will scan it for you to see.

The work required for one of my sketches is in excess of that required in SS so you see I do not change it very often. I apologise.

Quoted

Can you provide evidence this is true, cite a useful source for your assumption?

60-75m to land a propeller plane does not tell me much. Are we talking Sopwith Camel, Fairey Swordfish, Grumman Wildcat/Martlet or Fought Corsairs here?

While you may be able to land a Fiesler Storch or similar plane almost spot on against the wind on a carrier an unassisted landing of a much larger and heavier plane is an issue. So please back up your claim.

I made my approximation from watching the landing films of planes onto the jeep carriers. I looked at Bruce's response and looked at the videos again. He is right that I was incorrect. The landings were arrested. I do believe the plane in question was a Wildcat. I am certain you can find similar videos just searching on Google for escort carrier landings.

The S2F-1 Tracker (a large and heavy plane) landed regularly on the USS Point Crux. Unfortunately, I do not know the runway length they used to do so.

Quoted

Higher speeds help, for sure. The difference between a so-called jeep-carrier and a fleet carrier is about 10 knots of wind under the wings of a landing aircraft. You seem to have thought this through so I assume you can provide either historical data or at least some math to show those 10 knots make the huge difference you seem to take into account?

You'll have to wait for me to dig through the FAA standards and other aeronautic details (and calculations) before I can get back to you! But I do apologise because my initial claim was a claim from ignorance. I simply had a feeling that it would make a significant difference. If you look at my next post on the difference ship speed has on catapult launch length requires, you're see what sort of physics my feeling is based on.

It could be the case that I am totally wrong on this issue. I do not know yet which way it is.

Quoted

I do not object, thought this is an entire different field of operations. VTOL or helicopters need less space for take of and landing, but they still need space and are impacted by turbulences. Given deck size of your design compared to historical hyprid-designs I can see 6-8 spots to operate VTOL vehicles. That's not airstrike capability, but offers anti-submarine and SAR services.

However, we are talking a 1944er design I and think helicopters or other VTOL vehicles that offer such capability are still a long way ahead in time.

You mentioned helicopters, so my response was an admittance that helicopters could be employed on it usefully. It was not an endorsement of using the technology in the time period.

Quoted

Length, as well as weight and overall size of installation, heavily depends on the type of catapult you are using and what weights you are going to catapult. For example the Heinkel K-6, K-7 or K-9 catapults used on catapult ships like the Ostmark had a length of 41 to 41,5 meters and were capable to launch about 15 tons. Later versions allowed up to 20 tons [source Marinearchiv]. However, those were very bulky and heavy installations - as you can guess from line drawings of those ships. Is this what you had in mind for your ship?

Warships like BB or cruisers usually featured much smaller and less capable catapults, the largest and most powerful in this class probably were the Type 2 Mod.1 No.11 on the IJN Agano/Noshiro with 26m length or the Kure No.2 Mod.5 of 19,4m on the Yahagi/Sakawa. One should note that this is total length. The launching length actually was only 15,4m on the No.2 Mod.5, meant to accelerate 4 tons with 28m/sec [source LAcroix/Wells]. For comparison: The catapults used on German warships like the Prinz Eugen had a length of 14m [source Schmalenbach].

Well I can show you some calculations I did on the Ostmark class after your reply to show the length of catapult required to launch a similar plane into the air for my Scheme 5 design. From that we can extrapolate the approximate weight, length, etc. of a catapult on the Scheme 5. Since it is a bit long, I will have it in the next post rather than this one.

Quoted

The minimum flight deck length required to operate aircraft like a Swordfish, Wildcat or TBF successfully is about 400ft according to what has been discussed on these boards and elsewhere (e.g. warships1). This does not include simultaneous launch and recovery activities and it does not include the launch of large air strikes at a time for which there would be not enough space. Gives you an idea why the jeep-carriers were that size minimum.

I took it for granted that we all knew the limitations of a small flight deck were mainly in the inability to maintain a good sortie rate. Sortie rate is directly tied to flight deck size and there are no two ways about it, I said as much on the IRC. But you make this claim of discussion happening on the topic, I am quite interested in the contents of such a debate. Perhaps you could link me it?

In any case, 400 ft is about 125 m which was about the same as the original flight deck design length. The shortened deck length is indeed detrimental and I admit to it, but I have a need for clarification on the word successfully. What is successfully? For the current context, I treat successfully as able to fly a plane off and land given no time constraint.

Quoted

You have missed my point. I see no issues with superstructure set aside. The offset weight will be compensated by your designs flight deck and catapult installation (if any) or by bulges. With a constant air stream along the flight deck turbulences from the bridge are not more a problem than on any carrier. But what about your main guns? You placed them on your ships bow. Those heavy weights you cannot offset from your ships centreline to rule out turbulences. Although, on a second glimpse, it seems you are not using superfiring turrets. Which is very odd. It might allow you to raise your flight deck above gun level, so turbulences are ruled out. But then your second turret is between A turret and a high rising (top weight?) superstructure/flight deck combo. What kind of arc would that gun mount have? A very limited at best. So why install it at all and waste the weight?

Btw, the best hybrid-carrier in WesWorld probably was/is the Indian URUMI class. She has her guns aft...

I think I understand you now. The LCG of the gun systems results in a trim forward on the ship, which lends to the ship digging her bow into the water and increasing the power needed to propel at speed.
Well I ran the preliminary number crunching for the original dimensions (which admittedly are different from that of the actual Scheme 5) and that told me the LCB and LCG were both aft. There should be no such trimming issues.

To be honest, looking at the Indian URUMI class makes me wonder if the LCG is too far aft on the ship. Given the designs seem to have a V-shape fore and U-shape aft, I would think the LCG of the hull would likely be in the -4% to -6% range. The LCB of the ship would likely be in the -2% to -5% range. The additional weight of the turrets might be a problem, but of course I'm talking out of my ass. I haven't ran the numbers to validate my suspicion.

Thee guns are installed in a A-B configuration with no super-firing. The design distance between the turrets was 15m. The configuration should result in a lost of direct firing arc in front of the B turret of 30-40 degrees. However, I assume they are fighting at range where the elevation of the guns make the issue much less significant. I mean the space between the turrets is a little less than the space between the A and X turrets on the HMS Nelson and there is no B turret. I think the firing arcs aren't very restricted. I had the battery on deck level instead of super-firing because initially I was worried the KG would be too high (and later it served to lower recoil as well), although I didn't run any numbers on this.

Quoted

Don't know, but something's really odd about your Scheme 5. I'd really like to see a drawing... And while we are at it, do you consider 80 shells per barrel sufficient? Why?

The Deutschland and Scharnhorst 280mm guns had RoFs of 2.5 rd/min and 3.5 rd/min respectively, but they was their actual firing rate during battle.
For example, if we look at the performance of just the A turret of the HMS Rodney during the sinking of the Bismarck, the ammunition spent was 36, 46, 22. An average of 34.66 rounds in total over the 8.47 am to 10:10 am period.
This means an actual expenditure of 0.41 rds/min. Given that, the likely fighting time of a ship with 80 rounds per barrel is 195.1 mins or 3.25 hrs. That's long enough for most details.

Quoted

You missed my point. 8x28cm is impressive on a ship her size. The point I was to make is that a hybrid-carrier always is a compromise, even more so than any normal warship is anyway. Here you do not have armament compete with propulsion and armour alone, armament also competes with weight and size distributed to aircraft facilities. You also add the potential hazard of avgas fire to the ship As a result your ship will be less effective than a true cruiser or carrier and it cannot compensate being a true multi-role vessel because no role it really fits and succeeds in.

I agree with you. But my point was the problem you mention is only really witnessed once the air wing complement grows into a significant size. The weight for a handful of planes and their corresponding facilities is much less in portion to the plane count than for a few dozen planes. An airwing complement of 10-15 planes is small enough that it does not largely impact the propulsion/armor/firepower considerations. Of course I readily admit that the price you pay is a very low sortie rate and reduced effectiveness of the sorties.

But it did not lose much compared to the alternative design. I did do a Scheme 5A2 which resulted in the conclusion that the most I could get out was 50mm on the main belt (150mm -> 200mm). I was of the opinion that the air wing was more useful than 50mm of belt armor.

Quoted

Well, yes. For scouting and some anti-submarine patrol...

If launched at different times, I see no reason why a complement of 10 planes cannot "rotate" into the air. their loads and therefore missions do not have to be limited. Given that the planes will have to under go maintenance constantly, a group of 5 may be in the air with 5 going to launch and 5 in maintenance. Of course, the flight deck addition is because I did not consider the possibility of floatplane fighters such as mentioned in the IRC.

Quoted

Not sure if I can follow you here. The historical Deutschland featured 6x 18cm in triples on a long and slender cruiser hull and never had any troubles with recoil forces regarding hull strength or stability. And how is this related to speed? The Deutschland made up to 28 knots, so the difference it not great.

Also, who says you only fire full broadsides? If you don't stress is much reduced and you can use a ladder system increasing accuracy and keeping your opponent under constant fire....

So your argument is "a larger hull is better than a smaller hull"? No need to argue, but then again, why limit your design to something under 20,000 tons?

I was operating under the SS system of recoil and holding a maximum recoil limit of 0.88. I have not looked closely at the SS source code for recoil forces and I've worked enough with the code to know that it does not reflect reality at all. I won't try to derive from mechanics what recoil would mean really. As such I chose an arbitrary recoil limit for my designs to prevent recoil issues for occurring in service.

Besides you see the problem is the Deutschland features 6 x 28cm guns on a slender and small hull, but my design uses 8 barrels, not 6. If I go with a 6x28cm arrangement, the smallest I can go to while satisfying the arbitrary recoil limit is 13,000 tons on a 32 kn hull. For a 8x28cm battery, SS refuses to allow a ship smaller than Scheme 5 to attain 32 kn without going over 0.88 recoil.

As for size, I am of the opinion that utility increases linearly while the cost in tonnage for that utility is exponential. A ship that goes to 20,000 tons, for example, may be under consideration for a torpedo bulkhead would easily increase the weight by 3,000-8,000 tons. The tonnage limit to is to prevent that situation from occurring during my designing process.

Quoted

Drawing? You also need deckspace for other equipment. It's not only main guns...

Of course! But to be honest, secondary battery was only a minor consideration on my designs simply because they aren't very hard to fit in tonnage-wise. You can look at my sketch, extrapolate, and determine if I don't have enough deck-space, I will remove things accordingly.

Quoted

Guess I disagree...

I guess we do. But no hard feelings, it is just a simple thought experiment, I am not advocating for it.

I'll go through a bit of math on the subject of catapults to attempt to show the difference in take-off length achieved by changing ship speed.

Note: I apologise if a few things are not properly formatted. I originally wrote this in LaTeX but LaTeX is not supported on these forums

Let's assume a catapult like the Ostmark. Using the figures you gave (15t launch in 41-41.5m).

The take-off field length is by FAA recommendation and calculations:
Index = w^2/(sigma * C_Lmax * S_ref * T_.7_Vlo)

For 2 engine aircraft: TOFL = 857.4 + 28.43*Index + 0.0185*Index^2
For 3 engine aircraft: TOFL = 667.9 + 26.91*Index + 0.0123*Index^2
For 4 engine aircraft: TOFL = 486.7 + 26.20*Index + 0.0093*Index^2

Let's assume the Ostmark is launching a He-111 C-0 and is using a 15t max load catapult. The Ostmark moves at 13.5 kn.
The relevant details of the He-111
[list]Loaded Weight 9,610 kg (21,186 lb)
Wing Area 87.60 m^2 (942.94 ft^2)
Wing Loading 109.7 kg/m^2 (22.45 lb/ft^2)
2 Engines[/list]
Unfortunately I can't find the power output at takeoff for the BMW VI engine. The H-6 version uses the Jumo-211 as an engine and that is listed as 736 kW (986 hp) at take-off. I will use this number instead.

Index = (21,186 lb)^2/(1 * 22.45 lb/ft^2 * 942.94 ft^2 * 2*986 hp) = 10.752
TOFL = 1165.218 ft (355.158 m)

Usually the take-off speed is designated to be 1.2 V_s and assuming the He-111 has a stall speed just under 160 kph (36% of V_max), so the take-off speed is 53.332 m/s and the take-off time for the recommended TOFL is about 6.659 seconds.
Assuming the acceleration is constant, the acceleration provided by the engines is 8.009 m/s^2.

Now the Ostmark is moving at 13.5 kn or 6.945 m/s. If we locate ourselves in the frame of reference of the observer on the sea, stationary, watching the carrier and plane system, the system still requires 53.332 m/s of speed for the He-111 to take-off. On the frame of reference where we are on the deck however, the speed required is 46.387 m/s. Then for the He-111 to fly off of the Ostmark in 41m, the take-off time must be about 0.884 seconds. The average acceleration must be 52.482 m/s^2. If 8.009 m/s^2 of that number is provided by the engines, the remaining 44.473 m/s^2 must be provided by the catapult.

Alright this is everything we need now to calculate the TOFL on my Scheme 5 design .

Assuming we are still flying the He-111, the take-off speed is still 53.332 m/s. Because my ship is moving at 32 kn or 16.462 m/s, the required speed for take-off is 36.870 m/s. If like in the Ostmark the acceleration provided by the catapult/engine system is 52.482 m/s^2 then the take-off time is 0.314 seconds and the take-off length is 16.462 m.

So the difference between a 13.5 kn ship and a 32 kn ship, a 137% speed increase, is a reduction in runway length of 24.538 m or 60% of the runway length.

Edit: Corrected some units (kW->hp for example)

Here is the Scheme in question. You notice I do a lot of calculations before going to SS so I don't redraw/recalculate these for every Scheme!

The dimensions are for the original hull form, 200x20x7x0.538.

Interesting.

Thanks for calculations and drawing. Both offer more background - and more points to adress. However, I am occupied with family affairs so I may not be able to answer until next week. We'll see. Just wanted to let you know I saw your latest posts.

Quoted

Originally posted by HoOmAn
Interesting.

Thanks for calculations and drawing. Both offer more background - and more points to adress. However, I am occupied with family affairs so I may not be able to answer until next week. We'll see. Just wanted to let you know I saw your latest posts.

That is alright, I am interested in your feedback. A week or two is no big deal, I wait warmly.


In the meantime, I ran some numbers on the minimum gun size and shell weight to penetrate 400mm belt armor and 150mm deck armor at any range. Since I've ran 20" design studies a few weeks ago after Foxy made the suggestion of a Mexican 21" gun, the ideal gun fitting these conditions seems to be the USN 18"/47 gun firing the 3,850 lb shell.

I followed the design spiral more closely in this production and attempted to keep the ship well protected and in the 35,000t - 45,000t range. This is necessary to keep the ship "riskable" and not a SBB.

Quoted

BBL Scheme 7, "Light" Battleship laid down 1944

Displacement:
37,327 t light; 39,669 t standard; 45,000 t normal; 49,265 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(729.49 ft / 721.78 ft) x 104.99 ft x (34.45 / 37.02 ft)
(222.35 m / 220.00 m) x 32.00 m x (10.50 / 11.29 m)

Armament:
6 - 18.11" / 460 mm 47.0 cal guns - 3,858.09lbs / 1,750.00kg shells, 100 per gun
Breech loading guns in turret on barbette mounts, 1944 Model
2 x 3-gun mounts on centreline ends, evenly spread
20 - 5.12" / 130 mm 54.0 cal guns - 79.37lbs / 36.00kg shells, 150 per gun
Dual purpose guns in deck and hoist mounts, 1943 Model
10 x Twin mounts on sides, evenly spread
4 raised mounts
16 - 2.24" / 57.0 mm 60.0 cal guns - 6.61lbs / 3.00kg shells, 360 per gun
Auto rapid fire guns in deck and hoist mounts, 1942 Model
4 x Quad mounts on sides, evenly spread
24 - 0.79" / 20.0 mm 70.0 cal guns - 0.24lbs / 0.11kg shells, 750 per gun
Anti-air guns in deck mounts, 1944 Model
12 x Twin mounts on sides, evenly spread
Weight of broadside 24,848 lbs / 11,271 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 15.7" / 400 mm 469.16 ft / 143.00 m 10.76 ft / 3.28 m
Ends: 2.95" / 75 mm 249.34 ft / 76.00 m 10.76 ft / 3.28 m
3.28 ft / 1.00 m Unarmoured ends
Main Belt covers 100 % of normal length
Main Belt inclined 20.00 degrees (positive = in)

- Torpedo Bulkhead - Additional damage containing bulkheads:
2.95" / 75 mm 469.16 ft / 143.00 m 32.81 ft / 10.00 m
Beam between torpedo bulkheads 67.26 ft / 20.50 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 17.7" / 450 mm 5.91" / 150 mm 12.8" / 325 mm
2nd: 0.98" / 25 mm 0.59" / 15 mm 0.59" / 15 mm
3rd: 0.59" / 15 mm 0.20" / 5 mm 0.20" / 5 mm
4th: 0.59" / 15 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 5.91" / 150 mm
Forecastle: 5.91" / 150 mm Quarter deck: 5.91" / 150 mm

- Conning towers: Forward 15.24" / 387 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 125,134 shp / 93,350 Kw = 29.00 kts
Range 12,000nm at 18.00 kts
Bunker at max displacement = 9,596 tons

Complement:
1,544 - 2,008

Cost:
£25.144 million / $100.577 million

Distribution of weights at normal displacement:
Armament: 4,066 tons, 9.0 %
- Guns: 4,066 tons, 9.0 %
Armour: 14,319 tons, 31.8 %
- Belts: 3,749 tons, 8.3 %
- Torpedo bulkhead: 1,682 tons, 3.7 %
- Armament: 2,094 tons, 4.7 %
- Armour Deck: 6,380 tons, 14.2 %
- Conning Tower: 415 tons, 0.9 %
Machinery: 3,195 tons, 7.1 %
Hull, fittings & equipment: 15,446 tons, 34.3 %
Fuel, ammunition & stores: 7,673 tons, 17.1 %
Miscellaneous weights: 300 tons, 0.7 %
- Above deck: 300 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
65,183 lbs / 29,567 Kg = 21.9 x 18.1 " / 460 mm shells or 11.2 torpedoes
Stability (Unstable if below 1.00): 1.09
Metacentric height 6.3 ft / 1.9 m
Roll period: 17.5 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.87
Seaboat quality (Average = 1.00): 1.01

Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0.603 / 0.615
Length to Beam Ratio: 6.88 : 1
'Natural speed' for length: 31.25 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 70
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 22.64 ft / 6.90 m, 21.33 ft / 6.50 m
- Forward deck: 30.00 %, 21.33 ft / 6.50 m, 21.33 ft / 6.50 m
- Aft deck: 30.00 %, 21.33 ft / 6.50 m, 21.33 ft / 6.50 m
- Quarter deck: 20.00 %, 21.33 ft / 6.50 m, 21.33 ft / 6.50 m
- Average freeboard: 21.43 ft / 6.53 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 99.8 %
- Above water (accommodation/working, high = better): 152.4 %
Waterplane Area: 57,947 Square feet or 5,383 Square metres
Displacement factor (Displacement / loading): 113 %
Structure weight / hull surface area: 217 lbs/sq ft or 1,060 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.59
- Overall: 1.00
Adequate machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform

Looking at the picture, the ship is about 192 meters long at the waterline, not 200 meters. *runs away*

Love to see it try and squeeze through the Panama Canal...

One of the more amusing ideas I've had.

Edit: Whoops, forgot 1 of the 28cm turrets!

Quoted

BBL Scheme 8, Light Battleship laid down 1944

Displacement:
22,202 t light; 23,415 t standard; 25,007 t normal; 26,280 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(695.89 ft / 688.98 ft) x 93.50 ft x (26.90 / 27.90 ft)
(212.11 m / 210.00 m) x 28.50 m x (8.20 / 8.50 m)

Armament:
20 - 11.02" / 280 mm 47.0 cal guns - 716.50lbs / 325.00kg shells, 80 per gun
Breech loading guns in turret on barbette mounts, 1944 Model
4 x 5-gun mounts on centreline ends, evenly spread
1 raised mount - superfiring
8 - 5.12" / 130 mm 54.0 cal guns - 79.37lbs / 36.00kg shells, 150 per gun
Dual purpose guns in deck and hoist mounts, 1943 Model
4 x Twin mounts on sides, evenly spread
16 - 2.24" / 57.0 mm 60.0 cal guns - 6.61lbs / 3.00kg shells, 360 per gun
Auto rapid fire guns in deck and hoist mounts, 1942 Model
4 x Quad mounts on sides, evenly spread
12 - 0.79" / 20.0 mm 70.0 cal guns - 0.24lbs / 0.11kg shells, 750 per gun
Anti-air guns in deck mounts, 1944 Model
6 x Twin mounts on sides, evenly spread
Weight of broadside 15,074 lbs / 6,837 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 6.89" / 175 mm 360.89 ft / 110.00 m 10.76 ft / 3.28 m
Ends: Unarmoured
Main Belt covers 81 % of normal length
Main Belt inclined 20.00 degrees (positive = in)

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 18.9" / 480 mm 4.92" / 125 mm 12.8" / 325 mm
2nd: 0.98" / 25 mm 0.59" / 15 mm 0.59" / 15 mm
3rd: 0.59" / 15 mm 0.20" / 5 mm 0.20" / 5 mm
4th: 0.59" / 15 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 1.97" / 50 mm
Forecastle: 1.97" / 50 mm Quarter deck: 1.97" / 50 mm

- Conning towers: Forward 6.42" / 163 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 85,023 shp / 63,427 Kw = 29.00 kts
Range 12,000nm at 12.00 kts
Bunker at max displacement = 2,865 tons

Complement:
993 - 1,292

Cost:
£16.960 million / $67.842 million

Distribution of weights at normal displacement:
Armament: 3,460 tons, 13.8 %
- Guns: 3,460 tons, 13.8 %
Armour: 5,830 tons, 23.3 %
- Belts: 1,195 tons, 4.8 %
- Armament: 2,871 tons, 11.5 %
- Armour Deck: 1,646 tons, 6.6 %
- Conning Tower: 118 tons, 0.5 %
Machinery: 2,171 tons, 8.7 %
Hull, fittings & equipment: 10,391 tons, 41.6 %
Fuel, ammunition & stores: 2,804 tons, 11.2 %
Miscellaneous weights: 350 tons, 1.4 %
- Above deck: 350 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
32,537 lbs / 14,758 Kg = 48.6 x 11.0 " / 280 mm shells or 3.4 torpedoes
Stability (Unstable if below 1.00): 1.07
Metacentric height 5.2 ft / 1.6 m
Roll period: 17.3 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.79
Seaboat quality (Average = 1.00): 1.01

Hull form characteristics:
Hull has a flush deck,
a normal bow and large transom stern
Block coefficient (normal/deep): 0.505 / 0.512
Length to Beam Ratio: 7.37 : 1
'Natural speed' for length: 30.71 kts
Power going to wave formation at top speed: 52 %
Trim (Max stability = 0, Max steadiness = 100): 49
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 19.69 ft / 6.00 m, 19.69 ft / 6.00 m
- Forward deck: 30.00 %, 19.69 ft / 6.00 m, 19.69 ft / 6.00 m
- Aft deck: 30.00 %, 19.69 ft / 6.00 m, 19.69 ft / 6.00 m
- Quarter deck: 20.00 %, 19.69 ft / 6.00 m, 19.69 ft / 6.00 m
- Average freeboard: 19.69 ft / 6.00 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 79.5 %
- Above water (accommodation/working, high = better): 169.3 %
Waterplane Area: 44,845 Square feet or 4,166 Square metres
Displacement factor (Displacement / loading): 103 %
Structure weight / hull surface area: 200 lbs/sq ft or 976 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.96
- Longitudinal: 1.40
- Overall: 1.00
Excellent machinery, storage, compartmentation space
Excellent accommodation and workspace room

May be a sketch ???? I wonder how 4x5 will look like.

Never seen a 5gun turret only know the 4gun turret from DoY or PoW.

I never see quintuple turrets.
But sextuple, yes, in the US Tillman studies

There were 3 double mounts of 16" guns in a turret.

If US enginers could install 3 double mounts in a turret, you could too.


Jef

SS did not have a sextuple option, or else I would have chosen it. Although I see no reason why a sextuple could be done but a quintuple could not, I would have opted for the more familiar option if possible.

There is a 2-row sextuple option below the quad. Not what you want but it is a sextuple mount.

Logi-

here is my feedback as promised. :o)

Landing area:
When you talk of 60-75m for arrested landing - do you refer to the netto landing area (from plane hooked until stand still)? I ask because if this is the case, you need some more deck length because your plane will not catch a cable the first meter of the deck but probably within the first third. Considering this may add another 20-25m to your length for approx. 100m total. Add to that some space to move around and store a grounded a/c and you end up at about 120m (125m = 400ft). Would you agree?

For what it's worth, here is a discussion about minimum flight deck length - though this was triggered by take off length first place.

Catapulted take off calculations:
We were talking fleet carrier speed of 32kn versus jeep carrier speed of 20kn but you ran your calculations with 13,5kn. Why?

Gun installation:
I will comment on this when dealing with overall layout/drawing.

ROF/80 shells:
Working from a single incident, a single ship and a single turret does not provide a solid data base, IMHO. It is generally accepted that 1 shot/minute is a good approximation for sustained gun fire, based on flight time of a shell, spotting and adoption of results at common battle ranges. A very rough guess, of course, but I think it provides a better basis to calculate how long it will take until magazins run dry.

You may also consider that of 80 shells only a portion is AP while the rest is HE (usually). So should your ship encounter an armoured target like an enemy CA you will have a very limited source of ammo. In fact, should you be forced to seriously defend your ship, which requires a higher ROF of two to three shells per minute, you will run out of effective ammunition in about a quarter of an hour. I rate this a serious shortage of ammunition.

Compromise:
You wrote "An airwing complement of 10-15 planes is small enough that it does not largely impact the propulsion/armor/firepower considerations." and I disagree. Even such a small complement costs you lots of deck space, consumes much internal volume, requires additional flight direction/control equippment, a/c handling gear, tools, jigs, fuel, ammunition, adds a crew complement made of flying personal and maintenance experts who need workshops and the like. All this is alien on a warship designed for gun fights. Add to that the risk of avgas fire, limitations to gun, gun director and other equippment installation and you will see how seriously impacted your design is. In return that little complement is of little value overall.

You said you had the feeling your design offered enough deck space and empty tonnage to use it for a hybrid design. I have to admit, I have yet to read of any historical CA design that had plenty of room and space to spare. Usually the opposite is true, especially in times of war where light guns increased in number, weight and crews.

Recoil:
I cannot follow you on the 0.88 recoil limit. Can you elaborate?

Layout/drawing:
There are several points I'd like to address, some impacting each other.
- Main guns on deck level is fine. They seem adequately spaced, judging from the drawing. I wonder if both turrets could be moved forward a tad bit. Arcs for B turret are less impacted than I though, because there is no raised flight deck first place.
- The superstructure, although smaller than on a true CA, is still bulky and much wider than I had expected because you said it is reduced in size to reduce turbulences impacting flight operations and avoiding impact area in case of landing accidents. Judging from true CV or BBCV (there are several designs in Breyer's "BB and BC 1921-1996") your designs superstructure still is two to three times larger.
- Your flight deck will be heavily impacted by turbulences, both from gun installations and superstructure, as it is on weather deck level. The landing area is right behind the superstructure, asking for trouble. It will also be impacted by gun blast from the main guns, especially the launching area where your catapult equippment is. Of course there will be no launching operations during a gun fight but I wonder what damage will be done to the deck by cross-deck fire.
- You ships funnel seems to be on the superstructure. Judging from size and position I fear your flight deck might be impacted by smoke when steaming head long into wind at full speed.
- You said in the notes to sheme 5 there is a hangar of about 60x20x6m below deck aft. I think this cannot be, even more so as sheme 5 seems to be shorter than your original design the drawing belongs to. A tappering hull form and a block coefficient of approx. 0,5 speak against it, IMHO. All the hull above waterline aft would be consumed by that hangar. That's quite a lot - and you also need workshops and storage areas nearby. Seems to be too much given other installations you need aft on a ship like rudder engines etc. What impact such hangar has on designers ability to find room for crew quarters, equippment and stuff in general can only be guessed.
- Your hull needs to flare out heavily amidship to support that flight deck overhang. I think this will have a serious impact on ship handling in a swell or at speed. Waves will smash easily against that overhang, causing stress, causing spray impacting flight and general deck operations. I wonder what impact such overhang will have on maximum speed or if it can submerge in extreme situations, probably forcing the ship around.
- That lift does not make sense at all. A deck edge lift requires a large hole on the hull's side. With a hull height of 7m meters and a hangar height of 6m that opening would be about 60cm or less above waterline. Even the smalles wave will wash into your hangar. No good idea. The lift platform in lower position will be flooded almost permanently, no chance to serve any aircrafts. The hull flaring out poses the same issues I already mentioned above.
- Light gun installations are very difficult and I'd like to see your proposal. The superstructure is no good place because of blast effects from the main guns and added turbulences on the flight deck. Deck edge installations are no option also, because you have no raised flight deck. Thus deck edge installations would have to be too low on the hull, close above waterline, to avoid interference with flight operations; or else be above deck level, causing further turbulences and acting as a source for trouble should flight operations lead to some kind of emergency landing. B turret roof and, to some degree, her superstructure offer the only space for 20 mounts. And I am not even talking good arcs yet.

To sum it up: I think you need a raised flight deck with a hangar beneath but above weather deck level and a much reduced superstructure. This may cure some of the most serious problems with your design, but will add other points to consider too.

Well, these are my points. What do you say?

Quoted

Landing area:
When you talk of 60-75m for arrested landing - do you refer to the net to landing area (from plane hooked until stand still)? I ask because if this is the case, you need some more deck length because your plane will not catch a cable the first meter of the deck but probably within the first third. Considering this may add another 20-25m to your length for approx. 100m total. Add to that some space to move around and store a grounded a/c and you end up at about 120m (125m = 400ft). Would you agree?

I was mentioning the arrested landing with the implicit understanding it was from edge to stop and that it would be the third arrested cable that the pilot is caught on. My figure included the stern section that the plane does not actually touchdown on.

Of course, I agree that to store and move around A/Cs you would need on the order of 100-120m.

Quoted

Catapulted take off calculations:
We were talking fleet carrier speed of 32kn versus jeep carrier speed of 20kn but you ran your calculations with 13,5kn. Why?

I was using the Ostmark figures, which is a 13.5 kn speed. Since I was using their catapult (which you provided all the necessary data for calculations on) it only makes sense to use their ship speed as well.

Quoted

ROF/80 shells:
Working from a single incident, a single ship and a single turret does not provide a solid data base, IMHO. It is generally accepted that 1 shot/minute is a good approximation for sustained gun fire, based on flight time of a shell, spotting and adoption of results at common battle ranges. A very rough guess, of course, but I think it provides a better basis to calculate how long it will take until magazins run try.

I use the single turret only because it is uniform and does is the smallest data unit that should be counted when taking about the subject matter. If you look at the battle report on the other turrets (B and X), you will see that fire rate in the largely the same. The PoW is the only other ship in that action that was as heavily recorded in this regard but as you know, suffered from mechanical issues so it's data can not be used.

You should know that "generally accepted" does not hold water in any serious debate. The factors you mention form an upper bound on RoF but in no way forms a lower bound.

Quoted

You may also consider that of 80 shells only a portion is AP while the rest is HE (usually). So should your ship encounter an armoured target like an enemy CA you will have a very limited source of ammo. In fact, should you be forced to seriously defend your ship, which requires a higher ROF of two to three shells per minute, you will run out of effective ammunition in about a quarter of an hour. I rate this a serious shortage of ammunition.

Well you're making an opinion now. I can't and won't contest you on an opinion. Perhaps you can show me an example where a ship was contested and expended more than or close to 80 rounds per barrel in a short frame of time to justify your opinion?

Quoted

Compromise:
You wrote "An airwing complement of 10-15 planes is small enough that it does not largely impact the propulsion/armor/firepower considerations." and I disagree. Even such a small complement costs you lots of deck space, consumes much internal volume, requires additional flight direction/control equipment, a/c handling gear, tools, jigs, fuel, ammunition, adds a crew complement made of flying personal and maintenance experts who need workshops and the like. All this is alien on a warship designed for gun fights. Add to that the risk of avgas fire, limitations to gun, gun director and other equipment installation and you will see how seriously impacted your design is. In return that little complement is of little value overall.

I agree with what the drawbacks of an air-wing complement is.

However, you still miss the point of why I consider it to be a small impact on the design. By nature of the heavy recoil, the ship needs a higher GM. The method to achieve that, short of making drastic alterations of the hull and design is to increase the displacement of the hull. By nature of being a minimal design, most of this tonnage is not used. Hence all the deck space, internal volume, etc. is freed by the need for a high GM. It is precisely that the ship has an air-wing complement that this tonnage is used.

I strongly suspect if one would to draw the frame diagrams and internal subdivisions, you would find the air-wing complement does little to the vital internal volume. An added bonus is that the removal of the frame stiffeners and girders in the hangar region would help increase the GM of the ship. In short, I understand the risks inherent to the design such as AVGAS fire, but I disagree completely on how much you think the element impacts the design. Since we are but sitting back and discussing this design with no intent to draw such frames, I must propose we agree to disagree on this point.

Quoted

You said you had the feeling your design offered enough deck space and empty tonnage to use it for a hybrid design. I have to admit, I have yet to read of any historical CA design that had plenty of room and space to spare. Usually the opposite is true, especially in times of war where light guns increased in number, weight and crews.

Lack of knowledge of a historical design is not proof of it's impossibility. Personal incredulity and bandwagoning are not proper arguments and correlation does not equal causation.

You are making some very general statements, some of which are not connected to the design. What happens after the design is built based on the evolving strategic considerations is not the business of the naval architect.

Quoted

Recoil:
I cannot follow you on the 0.88 recoil limit. Can you elaborate?

I follow the understanding I was told of in Navalism that 1.00 recoil and recoils above 0.90 was something that should be avoided at all cost. Given that waas something widely accepted on the forum, I did not challenge it. As such the limit of 0.88 recoil was just an arbitrary limit set from this understanding.

Layout/drawing:

Quoted

- Main guns on deck level is fine. They seem adequately spaced, judging from the drawing. I wonder if both turrets could be moved forward a tad bit. Arcs for B turret are less impacted than I though, because there is no raised flight deck first place.

I kept them aft a bit because of my implicit understanding that SS sims the guns as behind the forecastle without question. I designed with this in mind so that the LCG would not be altered by SS's quirks. Of course, looking at it, it is probably possible I can reduce the forecastle length and move the turrets further fore.

Quoted

- The superstructure, although smaller than on a true CA, is still bulky and much wider than I had expected because you said it is reduced in size to reduce turbulences impacting flight operations and avoiding impact area in case of landing accidents. Judging from true CV or BBCV (there are several designs in Breyer's "BB and BC 1921-1996") your designs superstructure still is two to three times larger.

I must admit I am terrible at superstructure drawings. I absolutely can not draw them. What I do instead is draw a large box larger than what the actual superstructure will be and design placements in that fashion. You can see this in how the fore and aft bridges are just rectangles! The fact that the funnel is a trunked fat one is another indication of my lack of ability in this regard.

The real superstructure would probably look nothing like my drawing!

Quoted

- Your flight deck will be heavily impacted by turbulences, both from gun installations and superstructure, as it is on weather deck level. The landing area is right behind the superstructure, asking for trouble. It will also be impacted by gun blast from the main guns, especially the launching area where your catapult equipment is. Of course there will be no launching operations during a gun fight but I wonder what damage will be done to the deck by cross-deck fire.

I don't believe the turbulence from the gun installations will be very large given their nature and the relation of the flight deck to them. The turbluence of the superstructure depends on it's shape with is not defined. However, I urge you to push out some numbers regarding turbulence if you insist on making a key tenet of your argument.

Regarding main gun blast, there is no indication that the planes should land with the guns are firing. As for damage to the deck, perhaps you would pull up the documents regarding blast pressure from large caliber guns? I recall reading it but I am unable to find the documents now.

Given my (perhaps wrong) understanding of blast pressure, most of the force should be expelled in the 60 degrees arcs in front of the barrels. What remains is a very tiny fraction of the blast over pressure that quickly disperses in the surroundings. If you can produce the evidence of the range and force of the blast pressure, perhaps it would be best to shorten the flight deck by 5-10m.

Quoted

- You ships funnel seems to be on the superstructure. Judging from size and position I fear your flight deck might be impacted by smoke when steaming head long into wind at full speed.

Indeed, your caution is correct! But as I said, the superstructure drawing is not necessarily representative. I also see no reason why the funnels might not be corrected to output downwards and to the side, as some carrier designs in Wesworld do.

Quoted

- You said in the notes to Scheme 5 there is a hangar of about 60x20x6m below deck aft. I think this cannot be, even more so as Scheme 5 seems to be shorter than your original design the drawing belongs to. A tapering hull form and a block coefficient of approx. 0,5 speak against it, IMHO. All the hull above waterline aft would be consumed by that hangar. That's quite a lot - and you also need workshops and storage areas nearby. Seems to be too much given other installations you need aft on a ship like rudder engines etc. What impact such hangar has on designers ability to find room for crew quarters, equipment and stuff in general can only be guessed.

I operate with the understanding that the ship by itself is already over large for it's crew quarters and other equipment. Given that the ship was overly large already, I did not see a problem with shifting the crew quarters fore and devoted the rear to the hangar. Whether the understanding was incorrect is a different point(that we have been debating).

Of course, the hangar figure I give in Scheme 5 is not so much a definitive hangar size but actually just a reference for me. It was used to compute the maximum number of airplanes that could be carried by the Wesworld carrier rules. The hangar size I put is not actually meant to be used beyond that.

Quoted

- Your hull needs to flare out heavily amidship to support that flight deck overhang. I think this will have a serious impact on ship handling in a swell or at speed. Waves will smash easily against that overhang, causing stress, causing spray impacting flight and general deck operations. I wonder what impact such overhang will have on maximum speed or if it can submerge in extreme situations, probably forcing the ship around.

I am very doubtful of that (of the slamming issue, not of the flare). What is referred to as slamming is in general not applied to a ship's sides. Stresses of that manner are not very impacting on the overall structural integrity of the ship for the ship rolls with the force. Slamming is mostly an issue of the bow and stern for a ship does not generally pitch very much and there is much more resistance from the ship against the wave.

Of course, the ship's flight deck, although on deck, still decently high. A 7m flush deck is taller than of the New Orleans-class cruiser, from whom only very very seas barely touched the bow (and that was from pitching). In order for it to be an issue, you would have to show that this would occurs very frequently and calculate the approximate wave height. For that you would need to know the general region as well as the probability density function of wave height, calculated from the Rayleigh density functions, and then you would need to model how the ship responses to pitching and rolling. Both are a lot of work; physically, mentally, and computationally. You would need to fetch a supercomputer to run the NFA code to produce an accurate and reliable answer to your proposition. By naive analysis, a higher flight deck (above the hypothetical waves) would reduce GM and the righting moment and thereby make the ship more likely to roll over from the hypothetical waves than a lower flight deck.

As for the hull stresses, I did not calculate the horizontal bending moment of the deck and flight deck so I would not know how much of an impact your extreme condition would cause. I am very doubtful that your suggested condition would even occur, but that is another matter.

The problem is you are asking some very computationally hard problems as though they were trivial. The rest of your ideas in this quote follow from an extreme condition that you suppose is likely to happen without ever proving the condition (which is the mentioned computationally hard problem) is actually likely.

Quoted

- That lift does not make sense at all. A deck edge lift requires a large hole on the hull's side. With a hull height of 7m meters and a hangar height of 6m that opening would be about 60cm or less above waterline. Even the smalles wave will wash into your hangar. No good idea. The lift platform in lower position will be flooded almost permanently, no chance to serve any aircrafts. The hull flaring out poses the same issues I already mentioned above.

The hangar height you mention would indeed make things troublesome. It is something I overlooked. However, there is no reason it has to be that way and I suppose it would be better to move it inside the hull. The flaring issues I contest hotly.

Quoted

- Light gun installations are very difficult and I'd like to see your proposal. The superstructure is no good place because of blast effects from the main guns and added turbulences on the flight deck. Deck edge installations are no option also, because you have no raised flight deck. Thus deck edge installations would have to be too low on the hull, close above waterline, to avoid interference with flight operations; or else be above deck level, causing further turbulences and acting as a source for trouble should flight operations lead to some kind of emergency landing. B turret roof and, to some degree, her superstructure offer the only space for 20 mounts. And I am not even talking good arcs yet.

You mention turbulences like a dogma but have not computed the values or even estimates of such! Your whole line of thinking is flawed by the proposition. I do understand your point about good firing arcs, which may be somewhat lacking, but please revisit this argument after properly sorting it out.

Quoted

To sum it up: I think you need a raised flight deck with a hangar beneath but above weather deck level and a much reduced superstructure. This may cure some of the most serious problems with your design, but will add other points to consider too.

I believe a raised flight deck is both unnecessary and a bad design idea. It unnecessary raises the GM. Following through on such a suggestion would mean a radical alteration of the hull in order to keep GM at a satisfactory height. A reduced superstructure I do not contest. A volume rearranged superstructure ala Gerald Ford would also reduce air turbulence by more than 25%.

Respectfully, I feel most of the serious problems in my design that you see are but figments of your imagination. Most of them you have yet to demonstrate are realities!

I apologize for my harshness in replying, I mean it only to urge you to bring some data to the discussion. Although you make some valid points (which I amend myself to), many others are based on shaky premises which is not conductive to a proper reply.

Here's a design I came up for Australia using spare 15" triple turrets. Her roles would be as a training ships and convoy escort. Armored against heavy cruisers and light battlecruisers, and armed to seriously damage any convoy raider.



HMAS Australia, Australia Antartic Battleship laid down 1944

Displacement:
19,112 t light; 20,319 t standard; 22,950 t normal; 25,055 t full load

Dimensions: Length overall / water x beam x draught
706.78 ft / 700.00 ft x 90.00 ft x 25.00 ft (normal load)
215.43 m / 213.36 m x 27.43 m x 7.62 m

Armament:
6 - 15.00" / 381 mm guns (2x3 guns), 1,687.50lbs / 765.44kg shells, 1944 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread, 1 raised mount
16 - 4.70" / 119 mm guns (8x2 guns), 51.91lbs / 23.55kg shells, 1944 Model
Dual purpose guns in deck mounts with hoists
on side, evenly spread, 4 raised mounts
24 - 1.57" / 40.0 mm guns (8x3 guns), 1.95lbs / 0.89kg shells, 1944 Model
Anti-aircraft guns in deck mounts
on centreline, evenly spread, all raised mounts
20 - 0.79" / 20.0 mm guns (10x2 guns), 0.24lbs / 0.11kg shells, 1944 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 11,007 lbs / 4,993 kg
Shells per gun, main battery: 120
12 - 21.0" / 533.4 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 7.00" / 178 mm 410.00 ft / 124.97 m 10.00 ft / 3.05 m
Ends: Unarmoured
Main Belt covers 90 % of normal length

- Torpedo Bulkhead:
0.50" / 13 mm 410.00 ft / 124.97 m 20.00 ft / 6.10 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 10.0" / 254 mm 7.00" / 178 mm 10.0" / 254 mm

- Armour deck: 3.00" / 76 mm, Conning tower: 4.00" / 102 mm

Machinery:
Oil fired boilers, steam turbines,
Electric motors, 4 shafts, 40,446 shp / 30,173 Kw = 24.00 kts
Range 15,000nm at 15.00 kts
Bunker at max displacement = 4,735 tons

Complement:
931 - 1,211

Cost:
£13.248 million / $52.992 million

Distribution of weights at normal displacement:
Armament: 1,376 tons, 6.0 %
Armour: 5,334 tons, 23.2 %
- Belts: 1,249 tons, 5.4 %
- Torpedo bulkhead: 152 tons, 0.7 %
- Armament: 1,418 tons, 6.2 %
- Armour Deck: 2,445 tons, 10.7 %
- Conning Tower: 70 tons, 0.3 %
Machinery: 1,033 tons, 4.5 %
Hull, fittings & equipment: 11,270 tons, 49.1 %
Fuel, ammunition & stores: 3,838 tons, 16.7 %
Miscellaneous weights: 100 tons, 0.4 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
40,933 lbs / 18,567 Kg = 24.3 x 15.0 " / 381 mm shells or 6.1 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 5.2 ft / 1.6 m
Roll period: 16.6 seconds
Steadiness - As gun platform (Average = 50 %): 72 %
- Recoil effect (Restricted arc if above 1.00): 0.80
Seaboat quality (Average = 1.00): 1.35

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.510
Length to Beam Ratio: 7.78 : 1
'Natural speed' for length: 30.79 kts
Power going to wave formation at top speed: 40 %
Trim (Max stability = 0, Max steadiness = 100): 53
Bow angle (Positive = bow angles forward): 9.00 degrees
Stern overhang: 2.50 ft / 0.76 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 27.00 ft / 8.23 m
- Forecastle (15 %): 20.00 ft / 6.10 m
- Mid (30 %): 20.00 ft / 6.10 m
- Quarterdeck (19 %): 19.00 ft / 5.79 m
- Stern: 19.00 ft / 5.79 m
- Average freeboard: 19.98 ft / 6.09 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 78.7 %
- Above water (accommodation/working, high = better): 153.6 %
Waterplane Area: 44,062 Square feet or 4,094 Square metres
Displacement factor (Displacement / loading): 124 %
Structure weight / hull surface area: 189 lbs/sq ft or 920 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.98
- Longitudinal: 1.38
- Overall: 1.01
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily

Gun Blast

Regarding gun blast I'd like to address some points that you may find interesting to consider. I have only slightly touched the topic above because it is not the main issue I have with Logi's design, but it is one point on the list why I think his design scheme 1 (or 5) is not mature.

Logi worked under the impression that that the blast is "expelled in the 60 degrees arcs in front of the barrels" - which is not the case.

Please take a look on this US Navy Military Standard document. It is about gun blast and has a nice figure at the end showing peak overpressure contours for a 5"/54 with standard ammunition.

I also offer you this second document. It is not directly linked to naval guns but offers some nice figures showing gun blast pressure wave details and gun blast pressure impulses that help to understand the issue.

As we can learn from these documents, the blast does not affect the area in front of the gun only, but extends to the side and even behind the gun muzzle also. This is nothing special. It is true for all warships using classical guns ("classical" as in "no rail guns" ;o)). Just check the design of the Yamato class to see what impact heavy blast effects can have on ship design - boats stored in tunnels below deck and a cramped superstructure with directors and light guns under armored shields. This is, of course, an extreme example. So how is this linked to Logi's Scheme 1?

Logi presented a design with an all-forward main armament. As a result main guns cannot fire on a target in the ships aft sector. To reduce this blind spot as much as possible firing arcs have to be as large as possible, the main guns shall be possible to train aft beyond the limits usually set for ships with a standard layout. To allow this, the ships superstructure has to be slim and set back from the guns. We can see this on the line drawings of [URL=http://upload.wikimedia.org/wikipedia/commons/6/6b/HMS_Nelson,_outline_and_plan_(Warships_To-day,_1936).jpg]Nelson[/URL], Dunkerque or Richelieu . And we can also see it (partially) on the sketch Logi presented for Scheme 1.

However, these increased arcs also see the guns fire over a larger deck area than guns with a more limited arc would do. Hence a larger portion of the ship's deck and superstructure is affected by gun blast. According to D.K. Brown this meant for HMS Nelson that the blast of the guns disrupted officers on the bridge to such an extent that the guns of X turret were usually prohibited from firing abaft of the beam at high elevations. Fitting tempered glass in the bridge windows was tried, but gun blast shattered some of them and filled the bridge with flying debris. A great deal of effort was expended in correcting this problem, and fitting of protective ledges below the bridge windows proved successful.

This impact on decks and superstructure reduces space available to place equipment, or requires equipment place there to be protected (e.g. enclosed gun houses). As a result, historical designers moved all/most secondary and light guns well aft on the hulls of Nelson, Dunkerque and Richelieu where this equipment would be less affected. Only later in the war, when there was no or few axis capital ships still around and chances for big gun battles were reduced, light guns were place in the affected area to counter the ever increasing danger of air attacks (see Richelieu in her 1944er disguise). Coastal bombardments do not require an all-forward battleship to fire her main guns to the most extreme arcs aft. But even in 1945 the British were reluctant to place anything in the arcs of Nelson's main guns.

On a hybrid design as proposed by Logi things are a tad bit different, more severe I dare say. Due to the need for a large flight deck aft and abreast the superstructure there is even less space left to place secondary and tertiary armament, light projectors, directors and other delicate equipment. Looking at Logi's sketch you can see how B turret would fire all across the ships flight deck. As a response Logi proposed to move the flight deck further aft. But this is not possible if a 100m to 120m long angled flight deck is to be kept as a design feature. Moving the forward part of the flight deck with its installations (e.g. catapult, lights) aft results in a shorter flight deck; making air ops impossible as intended. The issue is more severe on Scheme 5 where the hull is 25m shorter (175m vs. 200m).

I'd like to know how Logi intends to take care of the gun blast issue for Scheme 1 (or 5). Where to place 4x2 100mm (including hoists and magazines below), 4x4 57mm and 12x2 20mm mounts, ensuring good arcs and an all-around anti-air defense capability? Where to place boats, directors, search/signal lights or ventilation trunks and other delicate equipment so they do not get damaged by use of the main guns? How to ensure flight deck installations are not affected/damaged?

Thanks for the documents.

Quoted

Logi worked under the impression that that the blast is "expelled in the 60 degrees arcs in front of the barrels" - which is not the case.

A point of nitpicking - The key modifying word there was "most" which you seem to have left out of your quote.

A brief skim of some documents that I have since obtained seems to validate the viewpoint:


Computational Fluid Dynamics Application to Gun Muzzle Blast - A Validation Case Study




Numerical Simulation of Muzzle Blast Overpressure in Antiaircraft Gun Muzzle Brake

Obviously it would do good for everyone to be aware that muzzle blast does exist after the 60 degrees and 90 degrees marks, but my statement should not be misrepresented.

Quoted

On a hybrid design as proposed by Logi things are a tad bit different, more severe I dare say.[ ...] Looking at Logi's sketch you can see how B turret would fire all across the ships flight deck. As a response Logi proposed to move the flight deck further aft. [...] The issue is more severe on Scheme 5 where the hull is 25m shorter (175m vs. 200m).

I believe we also discussed moving the guns forward some 20 ft combined with moving the flight deck further aft. But you are correct, on a 175m things are quite tight.

Quoted

I'd like to know how Logi intends to take care of the gun blast issue for Scheme 1 (or 5). Where to place 4x2 100mm (including hoists and magazines below), 4x4 57mm and 12x2 20mm mounts, ensuring good arcs and an all-around anti-air defense capability? Where to place boats, directors, search/signal lights or ventilation trunks and other delicate equipment so they do not get damaged by use of the main guns? How to ensure flight deck installations are not affected/damaged?

I've drawn up a very rough sketch of the layout on a lengthened (200m) Scheme 5 with the discussed changes. Let me know your thoughts.

I like the hybrid ideas. If you google Fleuzer, there was a lovely project in that vein. Do we have stats for this, because 100t do not cover a flight deck

The fleuzer carried 2*3 203 mm, an aft flight deck and 4 S-Boats on ~20 Gg