WesWorld

Seoul - Class, Chosen Oceangoing Submarine laid down 1944

Displacement:
1.248 t light; 1.278 t standard; 1.386 t normal; 1.472 t full load

Dimensions: Length overall / water x beam x draught
251,97 ft / 251,97 ft x 24,44 ft x 16,08 ft (normal load)
76,80 m / 76,80 m x 7,45 m x 4,90 m

Armament:
1 - 4,13" / 105 mm guns in single mounts, 35,32lbs / 16,02kg shells, 1944 Model
Breech loading gun in deck mount
on centreline forward, 1 raised gun
2 - 0,79" / 20,0 mm guns (1x2 guns), 0,24lbs / 0,11kg shells, 1944 Model
Machine guns in deck mount
on centreline amidships, all raised guns - superfiring
Weight of broadside 36 lbs / 16 kg
Shells per gun, main battery: 110
6 - 21,0" / 533,4 mm submerged torpedo tubes

Machinery:
Diesel Internal combustion engines plus batteries,
Electric cruising motors plus geared drives, 2 shafts, 3.197 shp / 2.385 Kw = 17,50 kts
Range 7.500nm at 10,00 kts
Bunker at max displacement = 194 tons

Complement:
113 - 147

Cost:
£0,396 million / $1,585 million

Distribution of weights at normal displacement:
Armament: 4 tons, 0,3%
Machinery: 82 tons, 5,9%
Hull, fittings & equipment: 912 tons, 65,8%
Fuel, ammunition & stores: 138 tons, 9,9%
Miscellaneous weights: 250 tons, 18,0%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1.021 lbs / 463 Kg = 28,9 x 4,1 " / 105 mm shells or 0,7 torpedoes
Stability (Unstable if below 1.00): 1,12
Metacentric height 0,8 ft / 0,2 m
Roll period: 11,8 seconds
Steadiness - As gun platform (Average = 50 %): 0 %
- Recoil effect (Restricted arc if above 1.00): 0,00
Seaboat quality (Average = 1.00): 0,00

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,490
Length to Beam Ratio: 10,31 : 1
'Natural speed' for length: 15,87 kts
Power going to wave formation at top speed: 45 %
Trim (Max stability = 0, Max steadiness = 100): 50
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: 0,00 ft / 0,00 m
- Forecastle (20%): 0,00 ft / 0,00 m
- Mid (50%): 0,00 ft / 0,00 m
- Quarterdeck (20%): 0,00 ft / 0,00 m
- Stern: 0,00 ft / 0,00 m
- Average freeboard: 0,00 ft / 0,00 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 71,9%
- Above water (accommodation/working, high = better): 0,0%
Waterplane Area: 4.066 Square feet or 378 Square metres
Displacement factor (Displacement / loading): 309%
Structure weight / hull surface area: 146 lbs/sq ft or 714 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 4,26
- Longitudinal: 2,27
- Overall: 2,66
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is extremely poor
Ship has quick, lively roll, not a steady gun platform
Caution: Lacks seaworthiness - very limited seakeeping ability

Only for internal use; not official
Diving depth: 266 feet
Emergency Depth: 400 feet
Crush Depth: 665 feet


Breakdown of Misc. Weight:
50 tons for torpedos
200 tons for ballast

As per the Springstyle notes, you would need a minimum of 231 tons of miscellaneous weights assigned to the ballast.

Few thoughts, I don't see anything that jumps out at me as illegal (note this is pre-caffeine) so take this as you will. You don't need both geared drives and electric motors, just the electric motors will suffice. The motors can accomplish the same thing as the gearing. Why no rear torpedo tubes? The only design I can think of from this era that lacks them is the Type XXI. The ship is just a bit long for a class 0 facility, is there a reason for this? Very nice drawing.

Quoted

You don't need both geared drives and electric motors, just the electric motors will suffice. The motors can accomplish the same thing as the gearing.

Don't know why, but I always sim subs with geared and electric. Geared drive for the diesel and electric drive for the batteries.

Quoted

Why no rear torpedo tubes? The only design I can think of from this era that lacks them is the Type XXI.

Perhaps to prevent the commander from running away and shooting at pursueing ships.

I've always just done electric. Makes sense to me that the diesels would just be turning electric generators no mater what, why add the additional complexity?

Taking a look here ...

http://www.ubootnet.de/Technik/Plaene/Bootsplaene.htm

Maybe I interpret the plans wrong, but I would say they have both .... but also the part behind the diesels could be the coupling / clutch for the electro motors .....

The drawing for the XXI is labeled .... at there is a "Dieselmotorengetriebe" = "Diesel engine Transmission / gear" mentioned.

So i think all subs have a geared drive

I would think they would have some sort of mechanical linkage, but when I see geared drive, I think of geared shaft linkages leading directly to the propellers.

From wiki regarding the Type VII:

Quoted

The boat was powered on the surface by two MAN AG, 6 cylinder, 4-stroke M6V 40/46 diesels giving a total of 2,100 to 2,310 brake horsepower (1,600 to 1,720 kW) at 470 to 485 rpm. When submerged it was propelled by two BBC GG UB 720/8 electric motors giving a total of 750 horsepower (560 kW) at 322 rpm.

Reading that, the electric motors are mentioned separate from the Diesels. It's Diesel + Electric and not diesel-electric which is what electric drive only would suggest. Looking at a picture of the VII, it is probably more correct to use direct drive than geared.

http://www.fleetsubmarine.com/propulsion.html

Looking at the images on that page, the top one would be simmed as geared + electric. The bottom one is electric drive only since it is diesel-electric.

Interesting - I just always simmed my subs with pure electric drives, since I figured that was normal.

I think both methods are fine, given that SS weights do not change with the drive type selector.