- 1
- 2

It's more a carrier than an aviation support vessel, or ?

Well, you could say that. 8)

It can operate aircraft, but it's rather slower than your run-of-the-mill aircraft carrier, and is intended to do things beyond the scope of said run-of-the-mill aircraft carrier. So I assigned a different title to the design.

I'm surprised at the large air group of 50 'assembled' aircraft. I guess these would be replacements plus probably some CAP fighters for itself. I'm guessing the operational idea is either to sail these in consort with a carrier task force as ready-use replacements (where its relatively weak gun and armour protection matter less under cover from a friendly carrier, buts its lower speed might impose restrictions), or more likely its role is to sail a complete replacement air wing to a force already deployed in the Atlantic (or beyond). Then its weaker protection might leave it more vulnerable. But given RN exercise experiences, any German carrier force would be heavily depleted if it reached the Atlantic and so such a ship makes sense to bring the main force back to strength and probably operate as a secondary replacement carrier in its own right. The only problem is a flattop this big is going to be a prime target whether its sailing as part of a main or reinforcing force and I'm not sure this design even with "enhanced damage control" is going to prove durable enough. Its an interesting concept though, but perhaps overly large for a peacetime role?

## Quoted

Westfalen, German Aviation Support Ship laid down 1947

Displacement:

12,200 t light; 12,640 t standard; 15,073 t normal; 17,019 t full load

Dimensions: Length overall / water x beam x draught

715.49 ft / 688.98 ft x 73.16 ft x 19.03 ft (normal load)

218.08 m / 210.00 m x 22.30 m x 5.80 m

Armament:

16 - 2.17" / 55.0 mm guns (8x2 guns), 5.08lbs / 2.30kg shells, 1947 Model

Automatic rapid fire guns in deck mounts with hoists

on side, evenly spread, all raised mounts

4 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1947 Model

Anti-aircraft guns in deck mounts

on side, all amidships, all raised mounts - superfiring

Weight of broadside 82 lbs / 37 kg

Shells per gun, main battery: 3,000

Armour:

- Belts: Width (max) Length (avg) Height (avg)

Main: 0.98" / 25 mm 421.59 ft / 128.50 m 9.84 ft / 3.00 m

Ends: Unarmoured

Main Belt covers 94 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)

Main: 0.98" / 25 mm 0.59" / 15 mm -

- Conning tower: 1.97" / 50 mm

Machinery:

Oil fired boilers, steam turbines,

Geared drive, 2 shafts, 42,989 shp / 32,070 Kw = 26.00 kts

Range 12,000nm at 18.00 kts

Bunker at max displacement = 4,379 tons

Complement:

679 - 884

Cost:

£4.262 million / $17.047 million

Distribution of weights at normal displacement:

Armament: 12 tons, 0.1 %

Armour: 213 tons, 1.4 %

- Belts: 173 tons, 1.1 %

- Torpedo bulkhead: 0 tons, 0.0 %

- Armament: 14 tons, 0.1 %

- Armour Deck: 0 tons, 0.0 %

- Conning Tower: 26 tons, 0.2 %

Machinery: 1,062 tons, 7.0 %

Hull, fittings & equipment: 5,912 tons, 39.2 %

Fuel, ammunition & stores: 2,873 tons, 19.1 %

Miscellaneous weights: 5,000 tons, 33.2 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship):

38,668 lbs / 17,539 Kg = 7,617.1 x 2.2 " / 55 mm shells or 3.7 torpedoes

Stability (Unstable if below 1.00): 1.10

Metacentric height 3.8 ft / 1.1 m

Roll period: 15.8 seconds

Steadiness - As gun platform (Average = 50 %): 70 %

- Recoil effect (Restricted arc if above 1.00): 0.02

Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:

Hull has a flush deck

and transom stern

Block coefficient: 0.550

Length to Beam Ratio: 9.42 : 1

'Natural speed' for length: 29.93 kts

Power going to wave formation at top speed: 42 %

Trim (Max stability = 0, Max steadiness = 100): 35

Bow angle (Positive = bow angles forward): 30.00 degrees

Stern overhang: 9.84 ft / 3.00 m

Freeboard (% = measuring location as a percentage of overall length):

- Stem: 28.87 ft / 8.80 m

- Forecastle (20 %): 28.87 ft / 8.80 m

- Mid (50 %): 28.87 ft / 8.80 m

- Quarterdeck (15 %): 28.87 ft / 8.80 m

- Stern: 28.87 ft / 8.80 m

- Average freeboard: 28.87 ft / 8.80 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 61.4 %

- Above water (accommodation/working, high = better): 296.6 %

Waterplane Area: 36,624 Square feet or 3,403 Square metres

Displacement factor (Displacement / loading): 203 %

Structure weight / hull surface area: 99 lbs/sq ft or 484 Kg/sq metre

Hull strength (Relative):

- Cross-sectional: 0.97

- Longitudinal: 1.98

- Overall: 1.04

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

Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Breakdown of miscellaneous weight

Air group - 50 aircraft - 2,500 tons

Crated spare aircraft for assembly - 30 a/c @ 25 tons - 750 tons

Air and surface warning radars - 100 tons

Fire control radars and gun directors - 100 tons

Flight operations center - 100 tons

Enhanced fire suppression system system - 100 tons

Aviation equipment - catapults, elevators, etc - 300 tons

Additional aviation workshop spaces - 400 tons

Additional accommodation spaces - 400 tons

25mm armored roof to box citadel - 250 tons

Armor comprises a box citadel around the magazines and engine spaces (83.9 meters) closed by bulkheads fore and aft.

Calculations for the armored roof derived from deck armor for a vessel 83.9 x 22.3 metres - 248 tons

## Quoted

I'm still not certain what she might be best classed as

You can keep on calling it an Aviation Support Ship. In the mean time, we will just keep on calling it a carrier.

## Quoted

Calculations for the armored roof derived from deck armor for a vessel 83.9 x 22.3 metres - 248 tons

There is one issue with this and it is something I was looking at with the armored flight deck of my 1948 carrier design....

You get 248 tons weight from a non-transom stern vessel of 83.9 x 22.3 m with a BC of 0.55, but at the part of the ship where that roof is probably needed, the BC is much, much higher than 0.55 meaning that part of that roof is not going to be armored.

Drawing it quickly, it is probably incorrect as I shrunk the ship as a whole meaning it still has the transom stern and it is probably in the wrong spot as well, but it will give you an idea what I am talking about:

Green is your armored roof, red is the the bit that should also be armored but isn't. Throwing it into SS, it looks like you would need 378 tons (using a BC of 0.95 and transom) to get a 25mm roof for the green and read area using the above situation. Depending on where exactly your roofed area is located, that value might vary a bit.

## Quoted

A 25mm 83.9 x 22.3m belt simmed in SS weighs 796 tons so this should be your minimum starting point for the armour for the roof of the box. You might need a bit extra for supporting structure?

Actually I quickly threw in some numbers (*) into SS and got 931 tons. Adding 200 feet to the length of the vessel changed it to 937 and removing 300 feet from the length of the vessel changed it to 902 tons. Using deck armor to sim that roof is flawed but using belt to figure out the weight of the deck is even less reliable.

Also I think that the material for belt armor is probably different from deck armor so there will be differences in density of the materials. 1 m^3 of deck armor does not necessarily have to be the same weights as 1m^3 of belt armor.

Another thing is that while the 25mm 83.9 x 22.3m belt gave me 937 tons, using the ends armor or torpedo bulkhead gives me 733 tons using the exact same dimensions.

And yet another thing is that the 931 tons I got from the main belt/upper belt is actually for 2 sides of the ships

All in all it seems better to use deck armor and set BC of the vessel at 1 or so to get the weight of the deck armor.

(*) I just went for a quick 800x80x20 ft design with a BC of 0.55 to give me the values

(**) with my sim, the actual size of the 25mm armored roof would be 108.28 x 44.6 m @ 931 tons.

733 tons is for 2 sides meaning for 1 side (and thus the proper measurements of the roof) it is 366.5 tons which comes pretty close to the 378 tons I calculated above with a 83.9 x 22.3 m vessel with a BC of 0.95.

## Quoted

Westfalen, German Aviation Support Ship laid down 1947

Displacement:

12,200 t light; 12,640 t standard; 15,073 t normal; 17,019 t full load

Dimensions: Length overall / water x beam x draught

715.49 ft / 688.98 ft x 73.16 ft x 19.03 ft (normal load)

218.08 m / 210.00 m x 22.30 m x 5.80 m

Armament:

16 - 2.17" / 55.0 mm guns (8x2 guns), 5.08lbs / 2.30kg shells, 1947 Model

Automatic rapid fire guns in deck mounts with hoists

on side, evenly spread, all raised mounts

4 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1947 Model

Anti-aircraft guns in deck mounts

on side, all amidships, all raised mounts - superfiring

Weight of broadside 82 lbs / 37 kg

Shells per gun, main battery: 3,000

Armour:

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)

Main: 0.98" / 25 mm 0.59" / 15 mm -

- Conning tower: 1.97" / 50 mm

Machinery:

Oil fired boilers, steam turbines,

Geared drive, 2 shafts, 42,989 shp / 32,070 Kw = 26.00 kts

Range 12,000nm at 18.00 kts

Bunker at max displacement = 4,379 tons

Complement:

679 - 884

Cost:

£4.262 million / $17.047 million

Distribution of weights at normal displacement:

Armament: 12 tons, 0.1 %

Armour: 40 tons, 0.3 %

- Belts: 0 tons, 0.0 %

- Torpedo bulkhead: 0 tons, 0.0 %

- Armament: 14 tons, 0.1 %

- Armour Deck: 0 tons, 0.0 %

- Conning Tower: 26 tons, 0.2 %

Machinery: 1,062 tons, 7.0 %

Hull, fittings & equipment: 5,985 tons, 39.7 %

Fuel, ammunition & stores: 2,873 tons, 19.1 %

Miscellaneous weights: 5,100 tons, 33.8 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship):

38,132 lbs / 17,296 Kg = 7,511.6 x 2.2 " / 55 mm shells or 3.7 torpedoes

Stability (Unstable if below 1.00): 1.10

Metacentric height 3.7 ft / 1.1 m

Roll period: 15.9 seconds

Steadiness - As gun platform (Average = 50 %): 70 %

- Recoil effect (Restricted arc if above 1.00): 0.02

Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:

Hull has a flush deck

and transom stern

Block coefficient: 0.550

Length to Beam Ratio: 9.42 : 1

'Natural speed' for length: 29.93 kts

Power going to wave formation at top speed: 42 %

Trim (Max stability = 0, Max steadiness = 100): 35

Bow angle (Positive = bow angles forward): 30.00 degrees

Stern overhang: 9.84 ft / 3.00 m

Freeboard (% = measuring location as a percentage of overall length):

- Stem: 28.87 ft / 8.80 m

- Forecastle (20 %): 28.87 ft / 8.80 m

- Mid (50 %): 28.87 ft / 8.80 m

- Quarterdeck (15 %): 28.87 ft / 8.80 m

- Stern: 28.87 ft / 8.80 m

- Average freeboard: 28.87 ft / 8.80 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 62.1 %

- Above water (accommodation/working, high = better): 296.6 %

Waterplane Area: 36,624 Square feet or 3,403 Square metres

Displacement factor (Displacement / loading): 205 %

Structure weight / hull surface area: 100 lbs/sq ft or 489 Kg/sq metre

Hull strength (Relative):

- Cross-sectional: 0.98

- Longitudinal: 2.01

- Overall: 1.05

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

Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Breakdown of miscellaneous weight

Air group - 50 aircraft - 2,500 tons

Crated spare aircraft for assembly - 28 a/c @ 25 tons - 700 tons

Air and surface warning radars - 100 tons

Fire control radars and gun directors - 100 tons

Flight operations center - 100 tons

Enhanced fire suppression system system - 100 tons

Aviation equipment - catapults, elevators, etc - 300 tons

Additional aviation workshop spaces - 700 tons

Additional accommodation spaces - 500 tons

## Quoted

What I did to simulate extra armor using misc. weight was to sim the portion of deck I wished the armor to cover (using the amount of extra armor desired) as deck armor, calculated the weight and then resimed the deck armor to the desired thickness.

.. so if that area covered is only 80% of the length, do you sim it as 80% of the length and get the same issue as I showed above with that image because you are not changing the BC, or do you use KISS and use 100% of a vessel's length?

## Quoted

but for a cruiser it should be fine as the armored deck size shouldn't change unless you change hull dimensions.

That does not necessarily have to be the case all the time. Even if hull dimensions do not change, there is still the possibility that you would need to calculate that deck armor with more beam. For example when you use bulges and due to the angled sides the beam of the ship higher up in the vessel is the same as the beam over the bulges. The armored deck higher in the vessel is going to be wider than the armored deck lower in the vessel and thus require more weight.

... having said that, I realize that I need to do a bit of recalculation on my carrier design...

When I sim boxes I don't generally sim the box roof because I assume the deck armour in the ship will count as the roof. Obviously that's a problem if your designing a ship without an armoured deck.

- 1
- 2

*Saturday, December 14th 2019, 4:38am*- Go to the top of the page

Forum Software: **Burning Board® Lite 2.1.2 pl 1**, developed by **WoltLab® GmbH**