WesWorld

I made a Corvette/Frigate for Chosen (stats will follow) and I need some advise concerning the appearance/layout as I am not competent with naval history. Does it look too modern for a late 1943 design? And if so, what should be altered?

I think her bow flares out too much, but that's probably just me.

Why the heavy tower between bridge and funnel? Wouldn't a standard main mast or tripod save a lot of weight?

That tower is probably where the Anti China Missile is located...

alternate variant:

It looks more modern than I'd expect a 1940s Korean product to be. Too many things look rounded and streamlined.

Quoted

Originally posted by Daidalos
alternate variant:

Without parameters to judge the picture by, making had and fast comments is rather difficult. Her lines are rather more modern for the 1940s - she looks rather Russian in her armament, and late 1950s/early 1960s Russian at that. The size of her gun houses suggests a medium caliber armament, or are they twins? It is far too early for short AS torpedoes, so the torpedo tubes shown on the drawing are probably not appropriate to a small corvette, unless this is meant to be some sort of fast attack vessel. Again, the lack of detailed specifications may lead to an incorrect assessment.

Posting the specs would help mightily.

Presuming the scale at the top is correct, the torpedo launchers themselves appear to be right about 10m in length, so I would hazard they are full size torpedoes. The usefulness of such on what would be guessed to be a slower speed escort type vessel is marginal, but to each their own.

Also judging by the scale at the top, it appears to be about 75m overall length, putting it somewhere between a Flower Class Corvette and a River Class Frigate.

Quoted

Geoje - Class, Chosen Frigate / Corvette laid down 1942

Displacement:
644 t light; 677 t standard; 851 t normal; 990 t full load

Dimensions: Length overall / water x beam x draught
219,46 ft / 213,25 ft x 33,79 ft x 9,19 ft (normal load)
66,89 m / 65,00 m x 10,30 m x 2,80 m

Armament:
4 - 3,94" / 100 mm guns (2x2 guns), 30,51lbs / 13,84kg shells, 1942 Model
Breech loading guns in deck mounts
on centreline ends, evenly spread, all raised mounts
2 - 0,50" / 12,7 mm guns in single mounts, 0,06lbs / 0,03kg shells, 1942 Model
Machine guns in deck mounts
on side, all amidships
20 - 0,79" / 20,0 mm guns (5x4 guns), 0,24lbs / 0,11kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 127 lbs / 58 kg
Shells per gun, main battery: 220
4 - 21,0" / 533 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2,76" / 70 mm 1,38" / 35 mm -
2nd: 1,38" / 35 mm 0,59" / 15 mm -
3rd: 0,79" / 20 mm 0,20" / 5 mm -

- Armour deck: 0,59" / 15 mm, Conning tower: 1,57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 1 shaft, 5.387 shp / 4.019 Kw = 21,00 kts
Range 5.000nm at 16,00 kts
Bunker at max displacement = 313 tons

Complement:
78 - 102

Cost:
£0,354 million / $1,415 million

Distribution of weights at normal displacement:
Armament: 16 tons, 1,9%
Armour: 72 tons, 8,4%
- Belts: 0 tons, 0,0%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 21 tons, 2,4%
- Armour Deck: 48 tons, 5,6%
- Conning Tower: 3 tons, 0,4%
Machinery: 141 tons, 16,5%
Hull, fittings & equipment: 365 tons, 42,9%
Fuel, ammunition & stores: 207 tons, 24,4%
Miscellaneous weights: 50 tons, 5,9%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1.649 lbs / 748 Kg = 54,1 x 3,9 " / 100 mm shells or 0,9 torpedoes
Stability (Unstable if below 1.00): 1,29
Metacentric height 1,5 ft / 0,5 m
Roll period: 11,4 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0,12
Seaboat quality (Average = 1.00): 1,02

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,450
Length to Beam Ratio: 6,31 : 1
'Natural speed' for length: 14,60 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 17,06 ft / 5,20 m
- Forecastle (20%): 10,83 ft / 3,30 m
- Mid (50%): 10,83 ft / 3,30 m
- Quarterdeck (15%): 10,83 ft / 3,30 m
- Stern: 10,83 ft / 3,30 m
- Average freeboard: 11,33 ft / 3,45 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 75,9%
- Above water (accommodation/working, high = better): 71,6%
Waterplane Area: 4.380 Square feet or 407 Square metres
Displacement factor (Displacement / loading): 161%
Structure weight / hull surface area: 52 lbs/sq ft or 253 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1,01
- Longitudinal: 3,33
- Overall: 1,14
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is cramped

Comments ?

I'd definitely make the main battery DP...

As has been noted, the main battery should be AA or DP. Realistically it is also far too heavy for such a small warship.

I question the usefulness of torpedo tubes on such a small vessel, unless its intent is to hunt surface vessels rather than submarines - and even then, they would of doubtful utility.

I doubt that there is sufficient deck space for two quad 20mm mounts on either beam abaft the bridge. The Springsharp notes them as raised mounts - it does not look that way on the drawing - they appear to be at deck level.

Deck armor seems to be a waste of tonnage, particularly as 15mm is barely acceptable for splinter protection; it will offer little protection from shell fire and air attack.

Quoted

Originally posted by BruceDuncan
As has been noted, the main battery should be AA or DP. Realistically it is also far too heavy for such a small warship.

Changed to 76mm .... still in use of the Chosen navy

Quoted

Originally posted by BruceDuncan
I question the usefulness of torpedo tubes on such a small vessel, unless its intent is to hunt surface vessels rather than submarines - and even then, they would of doubtful utility.

If you use this type of vessel more as escort than as subhunter ... torps are surely more usefull in that use-case.
So if he use this vessel as subhunter, i think the torps will be removed and instead DC-rails or a DC mortar will be installed

Quoted

Originally posted by BruceDuncan
I doubt that there is sufficient deck space for two quad 20mm mounts on either beam abaft the bridge. The Springsharp notes them as raised mounts - it does not look that way on the drawing - they appear to be at deck level.

Don't know if deck space is sufficient.
Sim corrected according to the drawing ... so now only 1 raised mount, other on deck level

Corrected version:

Quoted

Geoje - Class, Chosen Frigate / Corvette laid down 1943

Displacement:
652 t light; 677 t standard; 851 t normal; 990 t full load

Dimensions: Length overall / water x beam x draught
219,46 ft / 213,25 ft x 33,79 ft x 9,19 ft (normal load)
66,89 m / 65,00 m x 10,30 m x 2,80 m

Armament:
4 - 2,99" / 76,0 mm guns (2x2 guns), 13,39lbs / 6,08kg shells, 1942 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread, all raised mounts
2 - 0,50" / 12,7 mm guns in single mounts, 0,06lbs / 0,03kg shells, 1942 Model
Machine guns in deck mounts
on side, all amidships
20 - 0,79" / 20,0 mm guns (5x4 guns), 0,24lbs / 0,11kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, 1 raised mount
Weight of broadside 58 lbs / 27 kg
Shells per gun, main battery: 220
4 - 21,0" / 533 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2,76" / 70 mm 1,38" / 35 mm -
2nd: 1,38" / 35 mm 0,59" / 15 mm -
3rd: 0,79" / 20 mm 0,20" / 5 mm -

- Armour deck: 0,79" / 20 mm, Conning tower: 1,57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 1 shaft, 5.387 shp / 4.019 Kw = 21,00 kts
Range 5.000nm at 16,00 kts
Bunker at max displacement = 313 tons

Complement:
78 - 102

Cost:
£0,310 million / $1,239 million

Distribution of weights at normal displacement:
Armament: 7 tons, 0,9%
Armour: 82 tons, 9,7%
- Belts: 0 tons, 0,0%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 16 tons, 1,8%
- Armour Deck: 64 tons, 7,5%
- Conning Tower: 3 tons, 0,4%
Machinery: 141 tons, 16,5%
Hull, fittings & equipment: 347 tons, 40,7%
Fuel, ammunition & stores: 199 tons, 23,4%
Miscellaneous weights: 75 tons, 8,8%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1.743 lbs / 791 Kg = 130,1 x 3,0 " / 76 mm shells or 0,9 torpedoes
Stability (Unstable if below 1.00): 1,26
Metacentric height 1,5 ft / 0,5 m
Roll period: 11,6 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0,06
Seaboat quality (Average = 1.00): 1,02

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0,450
Length to Beam Ratio: 6,31 : 1
'Natural speed' for length: 14,60 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 0,00 ft / 0,00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 17,06 ft / 5,20 m
- Forecastle (20%): 10,83 ft / 3,30 m
- Mid (50%): 10,83 ft / 3,30 m
- Quarterdeck (15%): 10,83 ft / 3,30 m
- Stern: 10,83 ft / 3,30 m
- Average freeboard: 11,33 ft / 3,45 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 71,1%
- Above water (accommodation/working, high = better): 71,6%
Waterplane Area: 4.380 Square feet or 407 Square metres
Displacement factor (Displacement / loading): 171%
Structure weight / hull surface area: 49 lbs/sq ft or 240 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1,01
- Longitudinal: 3,19
- Overall: 1,13
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is cramped

Quoted

I doubt that there is sufficient deck space for two quad 20mm mounts on either beam abaft the bridge.

There's probably space on the sides for them, but there is probably no space for the superstructure in between them.
The beam of the ship is 10.3 meters, so it is not that difficult to imagine how it would look like. You have the side view of the aft firing mount and the steps on the scale bar are 10 meters.
There is also the usefulness of the second pair of mounts, the ones right next to the boats. I would think that the firing arc is probably less than 90 degrees on those when traversing.

Quoted

Deck armor seems to be a waste of tonnage, particularly as 15mm is barely acceptable for splinter protection; it will offer little protection from shell fire and air attack.

Probably splinter protection against any light caliber hits to the superstructure?

I should have said something about the role of this ship. It is not supposed to fill the role of the allied Corvettes in WWII. I wanted it to be more or less a kidn of mini-destroyer or a drastically enlarged MSB. It's intendend role is not sumarine hunting but attacking merchant ships and small escorts. Any warship more powerfull would be avoided by superior speed.
Dunno if that would work.
I will modify the drawing and reduce the quad mounts.

Superior speed?

21 knots makes this vessel dead meat for anything larger it might encounter. Such a speed is barely enough to hunt submarines, and is totally inadequate for a vessel intended to hunt MTBs. A destroyer would make mincemeat of this vessel, and would quickly run it down.

Quoted

Originally posted by BruceDuncan
Superior speed?

21 knots makes this vessel dead meat for anything larger it might encounter. Such a speed is barely enough to hunt submarines, and is totally inadequate for a vessel intended to hunt MTBs. A destroyer would make mincemeat of this vessel, and would quickly run it down.

I know, I know, I talked with parador about, which I should have done in the first place. It will be changed in the next sim.

Ditch deck armor, increase speed. When you get above 24 knots, then the hull strength can get as low as 0.50 for cross sectional. Having quickly looked at it myself, I think that the low l:b ratio might hurt potential high speed a bit...

Daidalos-

I think what you are looking for is pretty much what the SAE called light destroyer (LD). There were several classes. The latest, Bird class, is still in service, while two earlier classes have been completely sold to Mexico (well, surviving units, that is).

Those design may show what is possible, including drawing.

Well, you probably should ask Mexico so sell some of them for quick access or contact your local SAE arms dealer again... ;o)

changes:
- only 3x Quad (1aft, 1 each side)
- incresed speed
- 50tons misc weight for: radar, hydrophone, other extras (reserve)

Geoje - Class, Chosen Frigate / Corvette laid down 1942

Displacement:
862 t light; 890 t standard; 962 t normal; 1.020 t full load

Dimensions: Length overall / water x beam x draught
245,47 ft / 235,56 ft x 30,51 ft x 11,15 ft (normal load)
74,82 m / 71,80 m x 9,30 m x 3,40 m

Armament:
4 - 2,99" / 76,0 mm guns (2x2 guns), 13,39lbs / 6,07kg shells, 1942 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread
2 - 0,50" / 12,7 mm guns in single mounts, 0,06lbs / 0,03kg shells, 1942 Model
Machine guns in deck mounts
on side, all amidships
4 - 0,79" / 20,0 mm guns (1x4 guns), 0,24lbs / 0,11kg shells, 1942 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
8 - 0,79" / 20,0 mm guns (2x4 guns), 0,24lbs / 0,11kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 57 lbs / 26 kg
Shells per gun, main battery: 250
4 - 21,0" / 533 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2,76" / 70 mm 1,38" / 35 mm -
2nd: 1,38" / 35 mm 0,59" / 15 mm -
3rd: 0,79" / 20 mm 0,20" / 5 mm -

- Conning tower: 1,57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 23.611 shp / 17.614 Kw = 31,50 kts
Range 4.500nm at 12,00 kts
Bunker at max displacement = 130 tons

Complement:
86 - 112

Cost:
£0,646 million / $2,584 million

Distribution of weights at normal displacement:
Armament: 7 tons, 0,7%
Armour: 17 tons, 1,8%
- Belts: 0 tons, 0,0%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 14 tons, 1,5%
- Armour Deck: 0 tons, 0,0%
- Conning Tower: 3 tons, 0,3%
Machinery: 467 tons, 48,5%
Hull, fittings & equipment: 321 tons, 33,3%
Fuel, ammunition & stores: 100 tons, 10,4%
Miscellaneous weights: 50 tons, 5,2%

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
381 lbs / 173 Kg = 28,4 x 3,0 " / 76 mm shells or 0,3 torpedoes
Stability (Unstable if below 1.00): 1,25
Metacentric height 1,3 ft / 0,4 m
Roll period: 11,4 seconds
Steadiness - As gun platform (Average = 50 %): 44 %
- Recoil effect (Restricted arc if above 1.00): 0,08
Seaboat quality (Average = 1.00): 0,77

Hull form characteristics:
Hull has raised forecastle, rise forward of midbreak, low quarterdeck
and transom stern
Block coefficient: 0,420
Length to Beam Ratio: 7,72 : 1
'Natural speed' for length: 18,11 kts
Power going to wave formation at top speed: 77 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 2,62 ft / 0,80 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 20,01 ft / 6,10 m
- Forecastle (20%): 18,37 ft / 5,60 m (17,39 ft / 5,30 m aft of break)
- Mid (50%): 15,75 ft / 4,80 m (14,76 ft / 4,50 m aft of break)
- Quarterdeck (15%): 13,12 ft / 4,00 m (13,78 ft / 4,20 m before break)
- Stern: 13,12 ft / 4,00 m
- Average freeboard: 15,74 ft / 4,80 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 168,5%
- Above water (accommodation/working, high = better): 97,5%
Waterplane Area: 4.652 Square feet or 432 Square metres
Displacement factor (Displacement / loading): 71%
Structure weight / hull surface area: 30 lbs/sq ft or 148 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,50
- Longitudinal: 6,43
- Overall: 0,65
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather


Comments ?

Quoted

Originally posted by parador
Comments ?

70mm of armor on a 75mm gun is rather extreme. It'll raise the weight of the gunhouses and make them much harder and slower to turn.

By that same token, 35mm on the quad 20mm is also a bit much. Might I venture the following as a suggestion?

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 35 mm 15 mm -
2nd: 10 mm 10 mm -
3rd: 10 mm 10mm -

I think 40mm of conning tower is just right.