WesWorld

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.

U-10, Empire of Brazil Commerce Raider laid down 1944

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.

S-10, Empire of Brazil Commerce Raider laid down 1944

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.

Suggestion: buy a submarine instead. If you're doing commerce raiding, surface ships will just get spotted and tracked by aircraft. You either need to be able to hide out of sight, or hide in plain sight.

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. Your first design has the requisite amount of speed to at the very least not be easily caught, but it's displacement rivals that of a conventional destroyer. With much less armament, the same situation applies.

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.

Quoted from "Logi"

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.

I agree with what your saying. I have designed my very first submarine in response. it is loosely based off of the japanese B-1, though it is slightly smaller. It carries a single floatplane. This is intended to increase coverage while on operations in the Atlantic gap. additionally submarines can be tasked with providing reconnaissance of enemy bases. the aircraft has a radio and can rendezvous with friendly forces and report enemy activity if necessary.

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

dat formating. Hard to comment on.

sorry I didn't see the formatting until after I posted and so had to correct it. subsim is an excel sheet so formatting is a pain

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

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.

I like the floatplane on the B1. I agree that it can make the submarine much bigger than it needs to be, and so I wouldn't use a floatplane on most of my submarines, but I think it provides an interesting niche capability, especially for coordinating oceanic operations, which I consider to be important.