Hello again.

I decided to try my hand at designing a light commerce raider. the sustained speed requirement is less than my usual, as I do not see this ship acting with the fleet. she has 400 tons miscellaneous 50 for electronics and a depth charge rack. that can be used for extra fuel or plunder. (I'm only thinking very expensive items here as 350 tons is not enough to ship bulk cargo.

T-100, Empire of Brazil Comerce Raider laid down 1944

Displacement:

1,908 t light; 2,011 t standard; 2,300 t normal; 2,532 t full load

Dimensions: Length overall / water x beam x draught

450.00 ft / 450.00 ft x 42.00 ft x 9.00 ft (normal load)

137.16 m / 137.16 m x 12.80 m x 2.74 m

Armament:

3 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.92kg shells, 1944 Model

Dual purpose guns in deck mounts

on centreline ends, majority forward

16 - 1.46" / 37.0 mm guns (4x4 guns), 1.55lbs / 0.70kg shells, 1944 Model

Anti-aircraft guns in deck mounts

on side, evenly spread

8 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1944 Model

Anti-aircraft guns in deck mounts

on side, evenly spread

Weight of broadside 185 lbs / 84 kg

Shells per gun, main battery: 500

8 - 21.0" / 533.4 mm above water torpedoes

Armour:

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

Main: 1.00" / 25 mm 80.00 ft / 24.38 m 5.00 ft / 1.52 m

Ends: Unarmoured

Main Belt covers 27 % of normal length

Main belt does not fully cover magazines and engineering spaces

- Conning tower: 3.00" / 76 mm

Machinery:

Oil fired boilers, steam turbines,

Geared drive, 2 shafts, 32,737 shp / 24,422 Kw = 32.00 kts

Range 6,300nm at 15.00 kts

Bunker at max displacement = 521 tons

Complement:

165 - 215

Cost:

£1.367 million / $5.468 million

Distribution of weights at normal displacement:

Armament: 23 tons, 1.0 %

Armour: 34 tons, 1.5 %

- Belts: 22 tons, 1.0 %

- Torpedo bulkhead: 0 tons, 0.0 %

- Armament: 0 tons, 0.0 %

- Armour Deck: 0 tons, 0.0 %

- Conning Tower: 11 tons, 0.5 %

Machinery: 836 tons, 36.3 %

Hull, fittings & equipment: 615 tons, 26.7 %

Fuel, ammunition & stores: 392 tons, 17.1 %

Miscellaneous weights: 400 tons, 17.4 %

Overall survivability and seakeeping ability:

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

1,011 lbs / 459 Kg = 19.2 x 4.7 " / 120 mm shells or 0.5 torpedoes

Stability (Unstable if below 1.00): 1.32

Metacentric height 2.2 ft / 0.7 m

Roll period: 11.8 seconds

Steadiness - As gun platform (Average = 50 %): 60 %

- Recoil effect (Restricted arc if above 1.00): 0.06

Seaboat quality (Average = 1.00): 1.14

Hull form characteristics:

Hull has raised forecastle, raised quarterdeck

and transom stern

Block coefficient: 0.473

Length to Beam Ratio: 10.71 : 1

'Natural speed' for length: 24.16 kts

Power going to wave formation at top speed: 59 %

Trim (Max stability = 0, Max steadiness = 100): 53

Bow angle (Positive = bow angles forward): 0.00 degrees

Stern overhang: 0.00 ft / 0.00 m

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

- Stem: 22.00 ft / 6.71 m

- Forecastle (20 %): 22.00 ft / 6.71 m (13.00 ft / 3.96 m aft of break)

- Mid (50 %): 13.00 ft / 3.96 m

- Quarterdeck (20 %): 20.00 ft / 6.10 m (13.00 ft / 3.96 m before break)

- Stern: 20.00 ft / 6.10 m

- Average freeboard: 16.20 ft / 4.94 m

Ship tends to be wet forward

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 146.1 %

- Above water (accommodation/working, high = better): 135.8 %

Waterplane Area: 12,779 Square feet or 1,187 Square metres

Displacement factor (Displacement / loading): 100 %

Structure weight / hull surface area: 30 lbs/sq ft or 148 Kg/sq metre

Hull strength (Relative):

- Cross-sectional: 0.50

- Longitudinal: 0.86

- Overall: 0.53

Hull space for machinery, storage, compartmentation is cramped

Room for accommodation and workspaces is excellent

the reason for the 37 and 20 mm armament is for AA as I see that as being the primary threat to a commerce raider from the perspective of economics. hate to see a 10,000 dollar plane sink a 2 million dollar raider. rather a 10 million dollar cruiser did it. the raised quarterdeck is to provide for an elevated bridge and gun platform. she is designed more like a cargo vessel with guns than a destroyer.

I decided to try my hand at designing a light commerce raider. the sustained speed requirement is less than my usual, as I do not see this ship acting with the fleet. she has 400 tons miscellaneous 50 for electronics and a depth charge rack. that can be used for extra fuel or plunder. (I'm only thinking very expensive items here as 350 tons is not enough to ship bulk cargo.

T-100, Empire of Brazil Comerce Raider laid down 1944

Displacement:

1,908 t light; 2,011 t standard; 2,300 t normal; 2,532 t full load

Dimensions: Length overall / water x beam x draught

450.00 ft / 450.00 ft x 42.00 ft x 9.00 ft (normal load)

137.16 m / 137.16 m x 12.80 m x 2.74 m

Armament:

3 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.92kg shells, 1944 Model

Dual purpose guns in deck mounts

on centreline ends, majority forward

16 - 1.46" / 37.0 mm guns (4x4 guns), 1.55lbs / 0.70kg shells, 1944 Model

Anti-aircraft guns in deck mounts

on side, evenly spread

8 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1944 Model

Anti-aircraft guns in deck mounts

on side, evenly spread

Weight of broadside 185 lbs / 84 kg

Shells per gun, main battery: 500

8 - 21.0" / 533.4 mm above water torpedoes

Armour:

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

Main: 1.00" / 25 mm 80.00 ft / 24.38 m 5.00 ft / 1.52 m

Ends: Unarmoured

Main Belt covers 27 % of normal length

Main belt does not fully cover magazines and engineering spaces

- Conning tower: 3.00" / 76 mm

Machinery:

Oil fired boilers, steam turbines,

Geared drive, 2 shafts, 32,737 shp / 24,422 Kw = 32.00 kts

Range 6,300nm at 15.00 kts

Bunker at max displacement = 521 tons

Complement:

165 - 215

Cost:

£1.367 million / $5.468 million

Distribution of weights at normal displacement:

Armament: 23 tons, 1.0 %

Armour: 34 tons, 1.5 %

- Belts: 22 tons, 1.0 %

- Torpedo bulkhead: 0 tons, 0.0 %

- Armament: 0 tons, 0.0 %

- Armour Deck: 0 tons, 0.0 %

- Conning Tower: 11 tons, 0.5 %

Machinery: 836 tons, 36.3 %

Hull, fittings & equipment: 615 tons, 26.7 %

Fuel, ammunition & stores: 392 tons, 17.1 %

Miscellaneous weights: 400 tons, 17.4 %

Overall survivability and seakeeping ability:

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

1,011 lbs / 459 Kg = 19.2 x 4.7 " / 120 mm shells or 0.5 torpedoes

Stability (Unstable if below 1.00): 1.32

Metacentric height 2.2 ft / 0.7 m

Roll period: 11.8 seconds

Steadiness - As gun platform (Average = 50 %): 60 %

- Recoil effect (Restricted arc if above 1.00): 0.06

Seaboat quality (Average = 1.00): 1.14

Hull form characteristics:

Hull has raised forecastle, raised quarterdeck

and transom stern

Block coefficient: 0.473

Length to Beam Ratio: 10.71 : 1

'Natural speed' for length: 24.16 kts

Power going to wave formation at top speed: 59 %

Trim (Max stability = 0, Max steadiness = 100): 53

Bow angle (Positive = bow angles forward): 0.00 degrees

Stern overhang: 0.00 ft / 0.00 m

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

- Stem: 22.00 ft / 6.71 m

- Forecastle (20 %): 22.00 ft / 6.71 m (13.00 ft / 3.96 m aft of break)

- Mid (50 %): 13.00 ft / 3.96 m

- Quarterdeck (20 %): 20.00 ft / 6.10 m (13.00 ft / 3.96 m before break)

- Stern: 20.00 ft / 6.10 m

- Average freeboard: 16.20 ft / 4.94 m

Ship tends to be wet forward

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 146.1 %

- Above water (accommodation/working, high = better): 135.8 %

Waterplane Area: 12,779 Square feet or 1,187 Square metres

Displacement factor (Displacement / loading): 100 %

Structure weight / hull surface area: 30 lbs/sq ft or 148 Kg/sq metre

Hull strength (Relative):

- Cross-sectional: 0.50

- Longitudinal: 0.86

- Overall: 0.53

Hull space for machinery, storage, compartmentation is cramped

Room for accommodation and workspaces is excellent

the reason for the 37 and 20 mm armament is for AA as I see that as being the primary threat to a commerce raider from the perspective of economics. hate to see a 10,000 dollar plane sink a 2 million dollar raider. rather a 10 million dollar cruiser did it. the raised quarterdeck is to provide for an elevated bridge and gun platform. she is designed more like a cargo vessel with guns than a destroyer.

Displacement:

662 t light; 703 t standard; 860 t normal; 985 t full load

Dimensions: Length overall / water x beam x draught

248.17 ft / 245.00 ft x 23.00 ft x 9.50 ft (normal load)

75.64 m / 74.68 m x 7.01 m x 2.90 m

Armament:

1 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.92kg shells, 1944 Model

Dual purpose gun in deck mount

on centreline forward

12 - 1.46" / 37.0 mm guns (3x4 guns), 1.55lbs / 0.70kg shells, 1944 Model

Anti-aircraft guns in deck mounts

on side, evenly spread

8 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1944 Model

Anti-aircraft guns in deck mounts

on side, evenly spread

Weight of broadside 73 lbs / 33 kg

Shells per gun, main battery: 500

Machinery:

Oil fired boilers, steam turbines,

Geared drive, 2 shafts, 14,126 shp / 10,538 Kw = 28.00 kts

Range 6,200nm at 15.00 kts

Bunker at max displacement = 282 tons

Complement:

79 - 103

Cost:

£0.536 million / $2.145 million

Distribution of weights at normal displacement:

Armament: 9 tons, 1.1 %

Machinery: 349 tons, 40.6 %

Hull, fittings & equipment: 203 tons, 23.7 %

Fuel, ammunition & stores: 198 tons, 23.1 %

Miscellaneous weights: 100 tons, 11.6 %

Overall survivability and seakeeping ability:

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

289 lbs / 131 Kg = 5.5 x 4.7 " / 120 mm shells or 0.2 torpedoes

Stability (Unstable if below 1.00): 1.20

Metacentric height 0.8 ft / 0.2 m

Roll period: 11.0 seconds

Steadiness - As gun platform (Average = 50 %): 55 %

- Recoil effect (Restricted arc if above 1.00): 0.18

Seaboat quality (Average = 1.00): 1.04

Hull form characteristics:

Hull has raised forecastle

and transom stern

Block coefficient: 0.562

Length to Beam Ratio: 10.65 : 1

'Natural speed' for length: 17.66 kts

Power going to wave formation at top speed: 71 %

Trim (Max stability = 0, Max steadiness = 100): 53

Bow angle (Positive = bow angles forward): 10.00 degrees

Stern overhang: 0.00 ft / 0.00 m

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

- Stem: 18.00 ft / 5.49 m

- Forecastle (25 %): 18.00 ft / 5.49 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: 12.38 ft / 3.77 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 154.3 %

- Above water (accommodation/working, high = better): 104.9 %

Waterplane Area: 4,143 Square feet or 385 Square metres

Displacement factor (Displacement / loading): 96 %

Structure weight / hull surface area: 22 lbs/sq ft or 106 Kg/sq metre

Hull strength (Relative):

- Cross-sectional: 0.50

- Longitudinal: 2.91

- Overall: 0.60

Hull space for machinery, storage, compartmentation is cramped

Room for accommodation and workspaces is adequate

This was a response to the first. I felt it was grossly overweight for the role it needed to fill.

Displacement:

311 t light; 344 t standard; 450 t normal; 535 t full load

Dimensions: Length overall / water x beam x draught

202.47 ft / 200.00 ft x 21.00 ft x 8.00 ft (normal load)

61.71 m / 60.96 m x 6.40 m x 2.44 m

Armament:

1 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.91kg shells, 1944 Model

Dual purpose gun in deck mount

on centreline forward

12 - 1.46" / 37.0 mm guns (3x4 guns), 1.55lbs / 0.70kg shells, 1944 Model

Anti-aircraft guns in deck mounts

on side, evenly spread

8 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1944 Model

Anti-aircraft guns in deck mounts

on side, evenly spread

Weight of broadside 73 lbs / 33 kg

Shells per gun, main battery: 500

Machinery:

Oil fired boilers, steam turbines,

Geared drive, 2 shafts, 5,178 shp / 3,863 Kw = 24.00 kts

Range 6,200nm at 15.00 kts

Bunker at max displacement = 191 tons

Complement:

48 - 63

Cost:

£0.249 million / $0.998 million

Distribution of weights at normal displacement:

Armament: 9 tons, 2.0 %

Machinery: 132 tons, 29.4 %

Hull, fittings & equipment: 104 tons, 23.2 %

Fuel, ammunition & stores: 139 tons, 31.0 %

Miscellaneous weights: 65 tons, 14.4 %

Overall survivability and seakeeping ability:

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

204 lbs / 93 Kg = 3.9 x 4.7 " / 120 mm shells or 0.2 torpedoes

Stability (Unstable if below 1.00): 1.19

Metacentric height 0.7 ft / 0.2 m

Roll period: 10.8 seconds

Steadiness - As gun platform (Average = 50 %): 60 %

- Recoil effect (Restricted arc if above 1.00): 0.23

Seaboat quality (Average = 1.00): 1.07

Hull form characteristics:

Hull has raised forecastle

and transom stern

Block coefficient: 0.469

Length to Beam Ratio: 9.52 : 1

'Natural speed' for length: 16.26 kts

Power going to wave formation at top speed: 67 %

Trim (Max stability = 0, Max steadiness = 100): 56

Bow angle (Positive = bow angles forward): 10.00 degrees

Stern overhang: 0.00 ft / 0.00 m

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

- Stem: 14.00 ft / 4.27 m

- Forecastle (25 %): 14.00 ft / 4.27 m (8.00 ft / 2.44 m aft of break)

- Mid (50 %): 8.00 ft / 2.44 m

- Quarterdeck (15 %): 8.00 ft / 2.44 m

- Stern: 8.00 ft / 2.44 m

- Average freeboard: 9.50 ft / 2.90 m

Ship tends to be wet forward

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 130.9 %

- Above water (accommodation/working, high = better): 89.8 %

Waterplane Area: 2,829 Square feet or 263 Square metres

Displacement factor (Displacement / loading): 112 %

Structure weight / hull surface area: 18 lbs/sq ft or 90 Kg/sq metre

Hull strength (Relative):

- Cross-sectional: 0.50

- Longitudinal: 2.15

- Overall: 0.58

Hull space for machinery, storage, compartmentation is cramped

Room for accommodation and workspaces is cramped

I felt that this raider had to small and displacement and speed to operate effectively. this was upgraded to the U class. this is still a less expensive option.

Like Brock, I'm of the opinion that a submarine would be a much better choice instead. Given that this is 1945, submarines are not unreliable, I would venture to say there are few benefits to surface-based raiders as compared to submarines.

To add to what Brock said, your latest design is certainly not fast enough to avoid being caught. I expect maybe 1 or 2 merchant ships sunk at most, before being sunk in return. That assessment is with the proviso that the merchant marine is unescorted, which would not likely be the case for long. Versus an escorted merchant marine, I expect no ships sunk for one of these sunk.

It also presumes you're not up against an armed merchant, which is not a certain thing, either.

Date

1944

Ocean=1 Coast=0

1

misc crew

5

misc wt

50

Gun cal cm

12

ElecHP

2000

DieselHP

10000

H2O2HP

0

L

104.0 m

Beam

9.2 m

D

5.0 m

Crush depth

300 ft

sigma

670

#TT

6

mines

0

Tons Oil

290.0

Tons Battery

250.0

Tons H2O2

0

Cruise speed

15 knt

Submerged speed

5 knt

CREW

78

D_body

4.7

SpaceK

30.0

T_sheet

2.1

Structure mass

931.4 tn

wt gun

14.8 tn

misc wt

50 tn

wt TT

90 tn

wt mines

0 tn

wt motors

54 tn

wt diesel

141 tn

wt H2O2

0 tn

wt fuel&batts

540 tn

kerb wt

1821 tn

disp

2392 tn

res buoyancy

24%

Max Surf Spd

21.4 knt

Range

6304 nmi

Max Sub Spd

8.2 knt

Range

77 nmi

light weight

1531 tn

Cruise

Power

3450 hp

Submgd

power

456 hp

Its easier to manually transcribe it actually. As long as all the info is there that allows it to be resimed, its ok to do for Subsim reports

You smug-faced crowds with kindling eye

Who cheer when soldier lads march by,

Sneak home and pray you'll never know

The hell where youth and laughter go.

-Siegfried Sassoon

Who cheer when soldier lads march by,

Sneak home and pray you'll never know

The hell where youth and laughter go.

-Siegfried Sassoon

And comments on the design. The float-plane is a waste I think. Makes the sub much larger then it has to be for little gain. Maybe some additional underwater speed would be nice.

You smug-faced crowds with kindling eye

Who cheer when soldier lads march by,

Sneak home and pray you'll never know

The hell where youth and laughter go.

-Siegfried Sassoon

Who cheer when soldier lads march by,

Sneak home and pray you'll never know

The hell where youth and laughter go.

-Siegfried Sassoon

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