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61

Thursday, August 2nd 2012, 1:06am

Leopard class Corvette

After additional consideration and tweeking, the final design for the 1943 AS escorts has been finalized (I hope!)

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Leopard, German Corvette laid down 1943

Displacement: 1,000 t light; 1,062 t standard; 1,299 t normal; 1,488 t full load

Dimensions: Length overall / water x beam x draught

301.22 ft / 288.71 ft x 31.17 ft x 10.17 ft (normal load) [91.81 m / 88.00 m x 9.50 m x 3.10 m]

Armament:

2 - 4.13" / 105 mm guns (1x2 guns), 35.32lbs / 16.02kg shells, 1943 Model Dual purpose guns in a deck mount with hoist on centreline forward
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1943 Model Anti-aircraft guns in deck mounts on side, all amidships
2 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1938 Model Anti-aircraft guns in deck mounts on side, evenly spread, all raised mounts
Weight of broadside 77 lbs / 35 kg
Shells per gun, main battery: 800

Armour:

Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.98" / 25 mm 0.39" / 10 mm -
2nd: 0.39" / 10 mm 0.39" / 10 mm -
3rd: 0.39" / 10 mm 0.39" / 10 mm -

Conning tower: 0.79" / 20 mm

Machinery:

Diesel Internal combustion motors, Geared drive, 2 shafts, 14,013 shp / 10,454 Kw = 27.00 kts
Range 7,500nm at 15.00 kts
Bunker at max displacement = 426 tons

Complement: 107 - 140

Cost: £0.614 million / $2.455 million

Distribution of weights at normal displacement:

Armament: 10 tons, 0.7 %
Armour: 7 tons, 0.5 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 5 tons, 0.4 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.2 %
Machinery: 362 tons, 27.9 %
Hull, fittings & equipment: 521 tons, 40.1 %
Fuel, ammunition & stores: 299 tons, 23.0 %
Miscellaneous weights: 100 tons, 7.7 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship): 1,622 lbs / 736 Kg = 45.9 x 4.1 " / 105 mm shells or 0.6 torpedoes
Stability (Unstable if below 1.00): 1.19
Metacentric height 1.2 ft / 0.4 m
Roll period: 11.9 seconds
Steadiness - As gun platform (Average = 50 %): 59 %
- Recoil effect (Restricted arc if above 1.00): 0.17
Seaboat quality (Average = 1.00): 1.26

Hull form characteristics:

Hull has raised forecastle, rise forward of midbreak and transom stern
Block coefficient: 0.497
Length to Beam Ratio: 9.26 : 1
'Natural speed' for length: 19.52 kts
Power going to wave formation at top speed: 65 %
Trim (Max stability = 0, Max steadiness = 100): 47
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 21.65 ft / 6.60 m
- Forecastle (20 %): 18.37 ft / 5.60 m (17.39 ft / 5.30 m aft of break)
- Mid (50 %): 17.06 ft / 5.20 m (10.50 ft / 3.20 m aft of break)
- Quarterdeck (15 %): 10.50 ft / 3.20 m
- Stern: 10.50 ft / 3.20 m
- Average freeboard: 14.35 ft / 4.38 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 107.3 %
- Above water (accommodation/working, high = better): 150.5 %
Waterplane Area: 6,216 Square feet or 578 Square metres
Displacement factor (Displacement / loading): 143 %
Structure weight / hull surface area: 43 lbs/sq ft or 210 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.79
- Longitudinal: 3.61
- Overall: 0.92
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Good seaboat, rides out heavy weather easily

Breakdown of Miscellaneous Weight

Reserved for air and surface warning radar - 15 tons
Reserved for fire control and director radars - 15 tons
Reserved for sonar - 20 tons
Reserved for stand-off antisubmarine weapon - 20 tons
Reserved for ahead-thrown antisubmarine weapon - 10 tons
Reserved for A/S outfit - two depth charge racks, 48 depth charges - 20 tons

62

Sunday, September 2nd 2012, 3:36am

Spica class Light Minelayers

Proposed conversion of older R-11 class minecraft as specialized minelayers.

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Spica class German Light Minelayer laid down 1931

(Converted from R-11 class Minesweepers)


Displacement: 546 t light; 568 t standard; 678 t normal; 766 t full load

Dimensions: Length overall / water x beam x draught

235.87 ft / 229.66 ft x 26.25 ft x 7.87 ft (normal load) [71.89 m / 70.00 m x 8.00 m x 2.40 m]

Armament:

2 - 4.13" / 105 mm guns (1x2 guns), 35.32lbs / 16.02kg shells, 1931 Model Dual purpose guns in deck mount on centreline forward
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1938 Model Anti-aircraft guns in deck mounts on centreline ends, evenly spread, all raised mounts
4 - 0.79" / 20.0 mm guns (2x2 guns), 0.24lbs / 0.11kg shells, 1938 Model Anti-aircraft guns in deck mounts on centreline ends, evenly spread, all raised mounts
Weight of broadside 78 lbs / 35 kg
Shells per gun, main battery: 180

Armour:

Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.79" / 20 mm - -
2nd: 0.39" / 10 mm - -

Conning tower: 1.97" / 50 mm

Machinery:

Diesel Internal combustion motors, Geared drive, 2 shafts, 9,152 shp / 6,827 Kw = 25.00 kts
Range 4,000nm at 15.00 kts
Bunker at max displacement = 197 tons

Complement: 66 - 86

Cost: £0.278 million / $1.110 million

Distribution of weights at normal displacement:

Armament: 10 tons, 1.4 %
Armour: 7 tons, 1.0 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 3 tons, 0.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 3 tons, 0.5 %
Machinery: 259 tons, 38.2 %
Hull, fittings & equipment: 181 tons, 26.7 %
Fuel, ammunition & stores: 132 tons, 19.4 %
Miscellaneous weights: 90 tons, 13.3 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship): 282 lbs/128 Kg = 8.0 x 4.1"/105mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.24
Metacentric height 1.0 ft / 0.3 m
Roll period: 11.0 seconds
Steadiness - As gun platform (Average = 50 %): 67 %
- Recoil effect (Restricted arc if above 1.00): 0.15
Seaboat quality (Average = 1.00): 1.30

Hull form characteristics:

Hull has raised forecastle
Block coefficient: 0.500
Length to Beam Ratio: 8.75 : 1
'Natural speed' for length: 15.15 kts
Power going to wave formation at top speed: 67 %
Trim (Max stability = 0, Max steadiness = 100): 51
Bow angle (Positive = bow angles forward): 15.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 17.06 ft / 5.20 m
- Forecastle (33 %): 16.40 ft / 5.00 m (10.50 ft / 3.20 m aft of break)
- Mid (50 %): 10.50 ft / 3.20 m
- Quarterdeck (15 %): 10.50 ft / 3.20 m
- Stern: 10.50 ft / 3.20 m
- Average freeboard: 12.53 ft / 3.82 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 149.4 %
- Above water (accommodation/working, high = better): 121.7 %
Waterplane Area: 4,016 Square feet or 373 Square metres
Displacement factor (Displacement / loading): 94 %
Structure weight / hull surface area: 22 lbs/sq ft or 108 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 2.86
- Overall: 0.60
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Good seaboat, rides out heavy weather easily

Breakdown of Miscellaneous Weight

Air warning radar - 10 tons
Mine rails and mines - 80 tons

Refit/Conversion - Level III (cost 15% for vessels under 2,999 tons light)

Add radar
Modify armament
Modify superstructure to accommodate revised armament
Remove minesweeping equipment
Service life extension

Cost - 82 tons; Time - 43 days

63

Tuesday, September 4th 2012, 10:01pm

Jagd class Corvette

A proposal to modernize the eight F-7 class fleet escorts presently in service.

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Jagd, German Corvette laid down 1937

Displacement: 1,097 t light; 1,144 t standard; 1,351 t normal; 1,516 t full load

Dimensions: Length overall / water x beam x draught

291.88 ft / 278.87 ft x 34.45 ft x 9.84 ft (normal load) [88.96 m / 85.00 m x 10.50 m x 3.00 m]

Armament:

4 - 4.13" / 105 mm guns (2x2 guns), 35.32lbs / 16.02kg shells, 1928 Model Dual purpose guns in deck mounts on centreline ends, evenly spread
2 - 1.46" / 37.0 mm guns (1x2 guns), 1.55lbs / 0.70kg shells, 1937 Model Anti-aircraft guns in deck mount on centreline forward, all raised guns
8 - 0.79" / 20.0 mm guns (2x4 guns), 0.24lbs / 0.11kg shells, 1937 Model Anti-aircraft guns in deck mounts on side, all amidships, all raised mounts - superfiring
Weight of broadside 146 lbs / 66 kg
Shells per gun, main battery: 240

Armour:

Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.18" / 30 mm 0.79" / 20 mm -
2nd: 0.79" / 20 mm 0.79" / 20 mm -
3rd: 0.39" / 10 mm - -

Machinery:

Diesel Internal combustion motors, Geared drive, 2 shafts, 10,767 shp / 8,032 Kw = 25.00 kts
Range 6,000nm at 15.00 kts
Bunker at max displacement = 372 tons

Complement: 110 - 144

Cost: £0.521 million / $2.085 million

Distribution of weights at normal displacement:

Armament: 18 tons, 1.4 %
Armour: 11 tons, 0.8 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 11 tons, 0.8 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 298 tons, 22.1 %
Hull, fittings & equipment: 609 tons, 45.1 %
Fuel, ammunition & stores: 254 tons, 18.8 %
Miscellaneous weights: 160 tons, 11.8 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship): 2,479 lbs / 1,125 Kg = 70.2 x 4.1 " / 105 mm shells or 0.8 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 1.2 ft / 0.4 m
Roll period: 13.0 seconds
Steadiness - As gun platform (Average = 50 %): 73 %
- Recoil effect (Restricted arc if above 1.00): 0.18
Seaboat quality (Average = 1.00): 1.52

Hull form characteristics:

Hull has rise forward of midbreak and transom stern
Block coefficient: 0.500
Length to Beam Ratio: 8.10: 1
'Natural speed' for length: 19.39 kts
Power going to wave formation at top speed: 64 %
Trim (Max stability = 0, Max steadiness = 100): 48
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19.69 ft / 6.00 m
- Forecastle (20 %): 17.22 ft / 5.25 m
- Mid (80 %): 17.22 ft / 5.25 m (9.84 ft / 3.00 m aft of break)
- Quarterdeck (15 %): 9.84 ft / 3.00 m
- Stern: 9.84 ft / 3.00 m
- Average freeboard: 15.94 ft / 4.86 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 96.0 %
- Above water (accommodation/working, high = better): 192.0 %
Waterplane Area: 6,656 Square feet or 618 Square metres
Displacement factor (Displacement / loading): 148 %
Structure weight / hull surface area: 48 lbs/sq ft or 234 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.83
- Longitudinal: 5.04
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
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

Sonar - 20 tons
Radar - 10 tons
AS Outfit - 40 tons (AS Mortars, DC rails, DC)
AS Standoff Weapon - 20 tons
Helicopter - 50 tons
Growth - 20 tons

Changes - helicopter facilities expanded; AS standoff weapon fitted

Level II Minor Refit - Cost 5% (for vessels less than 2,999 tons light) - 55 tons; Time to complete - 16 days

64

Wednesday, September 5th 2012, 4:29pm

I have doubts about all that stuff fitting on the hull.

Helo ops on dedicated escorts seems very early. Landing on a small hull like that will be problematic.

65

Wednesday, September 5th 2012, 4:53pm

Canada's been very aggressive on naval helo ops, and the smallest ship currently under consideration for them is still in the 6-7 thousand ton range.

66

Wednesday, September 5th 2012, 4:55pm

He may be think on a ship like this ...

http://www.german-navy.de/kriegsmarine/s…1941/index.html

67

Wednesday, September 5th 2012, 5:18pm

Quoted

Originally posted by The Rock Doctor
I have doubts about all that stuff fitting on the hull.

Helo ops on dedicated escorts seems very early. Landing on a small hull like that will be problematic.


The design was prepared by Hrolf, my predecessor. In fact, I'm allocating greater tonnage for the helo operations than is in the existing F-7 design. The OTL Kriegsmarine did postulate operating the little Flettner Fl282 from vessels of this size, and I presume Hrolf ran with it. No one has heretofore objected.

68

Wednesday, September 5th 2012, 5:19pm

Quoted

Originally posted by ShinRa_Inc
Canada's been very aggressive on naval helo ops, and the smallest ship currently under consideration for them is still in the 6-7 thousand ton range.


The vessels were laid down for helo operations back in 1937. They've been in service for several years. I share your concerns, but I'm merely using what already exists.

69

Wednesday, September 5th 2012, 7:14pm

If there were concerns about operating helicopters on ships of this size, it probably ought to have been addressed in 1937 when Hrolf proposed the design.

Quoted

Originally posted by BruceDuncan
The OTL Kriegsmarine did postulate operating the little Flettner Fl282 from vessels of this size, and I presume Hrolf ran with it. No one has heretofore objected.

That's correct, he did cite that example in his original post. Hrolf's post said he intended to replace the forward 37mm gun with a forward-launching ASW weapon during wartime, as he didn't intend to develop anything standoff until that point.

70

Wednesday, September 5th 2012, 7:28pm

I'd definitely have flagged it in 1937, but wasn't around to do so.

71

Wednesday, September 5th 2012, 7:31pm

Quoted

Originally posted by The Rock Doctor
I'd definitely have flagged it in 1937, but wasn't around to do so.


The design for new construction corvettes - the Leopard class - do not have provision for operating a helicopter for the very reasons cited.

72

Wednesday, September 5th 2012, 7:35pm

Quoted

Originally posted by The Rock Doctor
I'd definitely have flagged it in 1937, but wasn't around to do so.

I'm aware, yes. I was around in 1937 and didn't do so myself, so I can't protest too much. *Shrug*

73

Friday, September 7th 2012, 11:27am

What is done is done. Given OTL German plans for such ships I see no problems. Yes they might not be effective helicopter ships but then the choppers themselves are low tech. This ain't no DASH-equiped frigate.

In fact do the Fl282 as yet have any offensive droppable payload yet? Or are they pure spotters?

74

Saturday, February 2nd 2013, 4:23am

Type IV Fleet Submarine Refit Scheme

A proposal to address a shortcoming of the older generation of German U-boats - no radar.

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Date: 1937
Type: Ocean
Crew: 51
Misc Weight: 20
Gun calibre: 10.5cm
Electric motors: 1,500 hp
Diesel engines: 5,200 hp
Length: 80.0 metres
Beam: 7.8 metres
Draught: 5.0 metres
Crush Depth: 250 metres
Torpedo tubes: Eight 533mm
Mines: 40
Tons Oil: 210
Tons Battery: 200
Cruise Speed: 10 knots
Submerged Speed: 4 knots
Kerb Weight: 1,184 tons
Displacement: 1,560
Reserve Buoyancy: 24%
Maximum Surfaced Speed: 18.2 knots
Max Submerged Speed: 8.2 knots
Light Weight: 934 tons
Range: 12,115 miles
Range: 144 miles

Armament is a 10.5cm gun forward, a 3.7cm AA gun aft and a twin 2cm AA machinegun on the aft end of the superstructure. 150 rounds are carried for the 10.5cm gun. 26 53.3cm torpedoes are normally carried, though some can be replaced with tube-launched mines.

Proposed refit: Increase miscellaneous weight by 16 tons (now total 20) to cover installation of air warning and surface search radar and a Metox radar threat warning receiver.

Cost of refit (2.5%): 24 tons. Time for refit: 8 days

75

Saturday, February 23rd 2013, 9:55pm

Z250 class Destroyer Refit Scheme

To address shortcomings in this class - inadequate radar.

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Refit Scheme

Zerstörer 250 class Fleet Destroyer

Displacement: 2,179 t light; 2,299 t standard; 2,552 t normal; 2,754 t full load

Dimensions: Length overall / water x beam x draught
393.14 ft / 377.30 ft x 37.73 ft x 14.76 ft (normal load)
119.83 m / 115.00 m x 11.50 m x 4.50 m

Armament:

6 - 5.04" / 128 mm guns (3x2 guns), 63.99lbs / 29.03kg shells, 1937 Model Dual purpose guns in deck mounts with hoists on centreline ends, majority forward, 1 raised mount - superfiring
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1937 Model Anti-aircraft guns in deck mounts on centreline, all aft, all raised mounts - superfiring
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1937 Model Anti-aircraft guns in deck mounts on side, evenly spread
16 - 0.79" / 20.0 mm guns (4x4 guns), 0.24lbs / 0.11kg shells, 1937 Model Machine guns in deck mounts on side, evenly spread, all raised mounts
Weight of broadside 400 lbs / 182 kg
Shells per gun, main battery: 300
8 - 23.6" / 600 mm above water torpedoes

Armour:

Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm 0.79" / 20 mm 1.97" / 50 mm
2nd: 0.79" / 20 mm 0.39" / 10 mm -
3rd: 0.79" / 20 mm 0.39" / 10 mm -
4th: 0.39" / 10 mm - -

Conning tower: 2.76" / 70 mm

Machinery:

Oil fired boilers, steam turbines, Geared drive, 2 shafts, 52,164 shp / 38,915 Kw = 35.00 kts, Range 5,000nm at 15.00 kts
Bunker at max displacement = 455 tons

Complement: 179 - 233

Cost: £1.607 million / $6.428 million

Distribution of weights at normal displacement:

Armament: 50 tons, 2.0 %
Armour: 41 tons, 1.6 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 29 tons, 1.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 11 tons, 0.4 %
Machinery: 1,260 tons, 49.4 %
Hull, fittings & equipment: 779 tons, 30.5 %
Fuel, ammunition & stores: 373 tons, 14.6 %
Miscellaneous weights: 50 tons, 2.0 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship): 707 lbs / 321 Kg = 11.1 x 5.0 " / 128 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.21
Metacentric height 1.6 ft / 0.5 m
Roll period: 12.4 seconds
Steadiness - As gun platform (Average = 50 %): 60 %
- Recoil effect (Restricted arc if above 1.00): 0.54
Seaboat quality (Average = 1.00): 1.01

Hull form characteristics:

Hull has a flush deck and transom stern
Block coefficient: 0.425
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 22.38 kts
Power going to wave formation at top speed: 69 %
Trim (Max stability = 0, Max steadiness = 100): 59
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 24.61 ft / 7.50 m
- Forecastle (20 %): 16.73 ft / 5.10 m
- Mid (50 %): 16.73 ft / 5.10 m
- Quarterdeck (15 %): 16.73 ft / 5.10 m
- Stern: 16.73 ft / 5.10 m
- Average freeboard: 17.36 ft / 5.29 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 177.9 %
- Above water (accommodation/working, high = better): 84.0 %
Waterplane Area: 9,247 Square feet or 859 Square metres
Displacement factor (Displacement / loading): 75 %
Structure weight / hull surface area: 41 lbs/sq ft or 199 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 2.43
- Overall: 0.58
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped

10 tons for depth charges and rails
25 tons for radar
15 tons reserved for future growth

Cost: 55 tons
Time to effect: 9 days