WesWorld

Per comments on the chat channel about the viability of trying to do an entire fleet's antisubmarine warfare work with even relatively small, expendable destroyers, I took a look at trying to put together a specialized sloop design for the job.

The thing is, since one of the things needed is the ability provide ASW cover for the main fleet, which is going to be moving at high speed, I'm really not certain that the difference in cost is worth the loss of the additional DD capabilities.

Also, I'm pretty sure that this is the first time Nordmark's tried to produce a fully automatic naval gun of any sort. I don't know much about them, so input is welcome.


AS46B, Nordmark ASW Sloop laid down 1946

Displacement:
1,095 t light; 1,144 t standard; 1,301 t normal; 1,426 t full load

Dimensions: Length overall / water x beam x draught
240.56 ft / 232.94 ft x 32.81 ft x 13.12 ft (normal load)
73.32 m / 71.00 m x 10.00 m x 4.00 m

Armament:
2 - 2.95" / 75.0 mm guns in single mounts, 13.23lbs / 6.00kg shells, 1946 Model
Automatic rapid fire guns in deck mounts with hoists
on centreline ends, evenly spread
8 - 1.57" / 40.0 mm guns (2x4 guns), 1.95lbs / 0.89kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on centreline ends, evenly spread, all raised mounts
Weight of broadside 42 lbs / 19 kg
Shells per gun, main battery: 800
5 - 24.0" / 610 mm above water torpedoes

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 24,182 shp / 18,040 Kw = 30.00 kts
Range 5,000nm at 15.00 kts
Bunker at max displacement = 282 tons

Complement:
107 - 140

Cost:
£0.881 million / $3.522 million

Distribution of weights at normal displacement:
Armament: 6 tons, 0.4 %
Machinery: 578 tons, 44.5 %
Hull, fittings & equipment: 386 tons, 29.7 %
Fuel, ammunition & stores: 206 tons, 15.8 %
Miscellaneous weights: 125 tons, 9.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
516 lbs / 234 Kg = 40.1 x 3.0 " / 75 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 1.1 ft / 0.3 m
Roll period: 13.0 seconds
Steadiness - As gun platform (Average = 50 %): 54 %
- Recoil effect (Restricted arc if above 1.00): 0.10
Seaboat quality (Average = 1.00): 0.98

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.454
Length to Beam Ratio: 7.10 : 1
'Natural speed' for length: 18.05 kts
Power going to wave formation at top speed: 77 %
Trim (Max stability = 0, Max steadiness = 100): 55
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 24.61 ft / 7.50 m
- Forecastle (15 %): 19.69 ft / 6.00 m
- Mid (50 %): 16.40 ft / 5.00 m
- Quarterdeck (15 %): 16.40 ft / 5.00 m
- Stern: 16.40 ft / 5.00 m
- Average freeboard: 17.77 ft / 5.42 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 159.2 %
- Above water (accommodation/working, high = better): 63.9 %
Waterplane Area: 5,081 Square feet or 472 Square metres
Displacement factor (Displacement / loading): 94 %
Structure weight / hull surface area: 32 lbs/sq ft or 155 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 8.11
- Overall: 0.66
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

Well, this takes a rather different approach to the subject, but take a look at this for a fleet sloop. It keeps your speed characteristics in mind.

-----

TBD, TBD TBD laid down 1945

Displacement:
1,275 t light; 1,359 t standard; 1,643 t normal; 1,870 t full load

Dimensions: Length overall / water x beam x draught
336.70 ft / 328.08 ft x 32.48 ft x 11.48 ft (normal load)
102.63 m / 100.00 m x 9.90 m x 3.50 m

Armament:
4 - 3.54" / 90.0 mm guns (2x2 guns), 22.24lbs / 10.09kg shells, 1945 Model
Automatic rapid fire guns in deck mounts with hoists
on centreline ends, evenly spread
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1945 Model
Anti-aircraft guns in deck mounts
on centreline ends, evenly spread, all raised mounts
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1945 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
2 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1945 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 105 lbs / 48 kg
Shells per gun, main battery: 800
4 - 21.0" / 533 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.98" / 25 mm 0.79" / 20 mm -
2nd: 0.59" / 15 mm 0.59" / 15 mm -
3rd: 0.59" / 15 mm 0.59" / 15 mm -
4th: 0.39" / 10 mm - -

- Conning tower: 1.57" / 40 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 23,054 shp / 17,198 Kw = 30.00 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 511 tons

Complement:
128 - 167

Cost:
£0.961 million / $3.842 million

Distribution of weights at normal displacement:
Armament: 15 tons, 0.9 %
Armour: 17 tons, 1.0 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 12 tons, 0.7 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 5 tons, 0.3 %
Machinery: 582 tons, 35.4 %
Hull, fittings & equipment: 561 tons, 34.1 %
Fuel, ammunition & stores: 368 tons, 22.4 %
Miscellaneous weights: 100 tons, 6.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,070 lbs / 485 Kg = 48.1 x 3.5 " / 90 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.15
Metacentric height 1.2 ft / 0.4 m
Roll period: 12.4 seconds
Steadiness - As gun platform (Average = 50 %): 79 %
- Recoil effect (Restricted arc if above 1.00): 0.25
Seaboat quality (Average = 1.00): 1.41

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.470
Length to Beam Ratio: 10.10 : 1
'Natural speed' for length: 20.73 kts
Power going to wave formation at top speed: 66 %
Trim (Max stability = 0, Max steadiness = 100): 56
Bow angle (Positive = bow angles forward): 22.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 21.33 ft / 6.50 m
- Forecastle (25 %): 18.04 ft / 5.50 m
- Mid (50 %): 14.76 ft / 4.50 m
- Quarterdeck (25 %): 14.76 ft / 4.50 m
- Stern: 14.76 ft / 4.50 m
- Average freeboard: 16.32 ft / 4.98 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 131.4 %
- Above water (accommodation/working, high = better): 123.6 %
Waterplane Area: 7,184 Square feet or 667 Square metres
Displacement factor (Displacement / loading): 117 %
Structure weight / hull surface area: 36 lbs/sq ft or 177 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.60
- Longitudinal: 3.39
- Overall: 0.71
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily

Miscellaneous Weight - 100 tons, comprising

Reserved for air warning radar - 30 tons
Reserved for fire control radar - 30 tons
Reserved for A/S detection equipment - 30 tons
Reserved for future growth or not yet allocated - 10 tons

Bruce's suggestion is pretty similar to my own, actually. In France, both I and AdmK built some pretty similar ships (the Zephir class and the Le Breton class).

Quoted from "Brockpaine"

Bruce's suggestion is pretty similar to my own, actually. In France, both I and AdmK built some pretty similar ships (the Zephir class and the Le Breton class).

Myself, I wouldn't put torpedoes on a dedicated ASW vessel, but YMMV. The miscellaneous weight could be played with a bit too to suit your own doctrine.

*looks at the seaboat rating*

*copies the basic plan, fiddles around a bit*

*looks at the seaboat rating again*

What black magic is this?!





AS46C, Nordmark ASW Sloop laid down 1946

Displacement:
1,049 t light; 1,128 t standard; 1,384 t normal; 1,589 t full load

Dimensions: Length overall / water x beam x draught
334.84 ft / 328.08 ft x 29.53 ft x 12.47 ft (normal load)
102.06 m / 100.00 m x 9.00 m x 3.80 m

Armament:
4 - 3.54" / 90.0 mm guns in single mounts, 22.24lbs / 10.09kg shells, 1946 Model
Automatic rapid fire guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on centreline ends, evenly spread, all raised mounts
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, all amidships
Weight of broadside 105 lbs / 47 kg
Shells per gun, main battery: 800
4 - 24.0" / 610 mm above water torpedoes

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 19,778 shp / 14,755 Kw = 30.00 kts
Range 8,000nm at 15.00 kts
Bunker at max displacement = 461 tons

Complement:
113 - 147

Cost:
£0.842 million / $3.368 million

Distribution of weights at normal displacement:
Armament: 15 tons, 1.1 %
Machinery: 494 tons, 35.7 %
Hull, fittings & equipment: 430 tons, 31.1 %
Fuel, ammunition & stores: 335 tons, 24.2 %
Miscellaneous weights: 110 tons, 7.9 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
711 lbs / 322 Kg = 32.0 x 3.5 " / 90 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.17
Metacentric height 1.1 ft / 0.3 m
Roll period: 12.0 seconds
Steadiness - As gun platform (Average = 50 %): 87 %
- Recoil effect (Restricted arc if above 1.00): 0.43
Seaboat quality (Average = 1.00): 1.75

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.401
Length to Beam Ratio: 11.11 : 1
'Natural speed' for length: 20.77 kts
Power going to wave formation at top speed: 62 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19.69 ft / 6.00 m
- Forecastle (15 %): 16.40 ft / 5.00 m
- Mid (50 %): 14.76 ft / 4.50 m
- Quarterdeck (15 %): 14.76 ft / 4.50 m
- Stern: 14.76 ft / 4.50 m
- Average freeboard: 15.49 ft / 4.72 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 136.0 %
- Above water (accommodation/working, high = better): 99.4 %
Waterplane Area: 6,192 Square feet or 575 Square metres
Displacement factor (Displacement / loading): 113 %
Structure weight / hull surface area: 29 lbs/sq ft or 142 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 3.22
- Overall: 0.60
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

A point to ponder is the percentage of fuel. The bunkers are close to 25% of the total weight; that is nearing the edge of the envelope IMHO.

Easy enough to deal with.


AS46D, Nordmark ASW Sloop laid down 1946

Displacement:
1,016 t light; 1,092 t standard; 1,277 t normal; 1,425 t full load

Dimensions: Length overall / water x beam x draught
334.84 ft / 328.08 ft x 29.53 ft x 12.14 ft (normal load)
102.06 m / 100.00 m x 9.00 m x 3.70 m

Armament:
4 - 3.54" / 90.0 mm guns in single mounts, 22.24lbs / 10.09kg shells, 1946 Model
Automatic rapid fire guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, all forward
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, all aft
Weight of broadside 105 lbs / 47 kg
Shells per gun, main battery: 800
4 - 24.0" / 610 mm above water torpedoes

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 18,555 shp / 13,842 Kw = 30.00 kts
Range 6,000nm at 15.00 kts
Bunker at max displacement = 332 tons

Complement:
106 - 138

Cost:
£0.803 million / $3.213 million

Distribution of weights at normal displacement:
Armament: 15 tons, 1.2 %
Machinery: 463 tons, 36.3 %
Hull, fittings & equipment: 427 tons, 33.4 %
Fuel, ammunition & stores: 261 tons, 20.4 %
Miscellaneous weights: 110 tons, 8.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
649 lbs / 294 Kg = 29.2 x 3.5 " / 90 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.13
Metacentric height 1.0 ft / 0.3 m
Roll period: 12.3 seconds
Steadiness - As gun platform (Average = 50 %): 92 %
- Recoil effect (Restricted arc if above 1.00): 0.47
Seaboat quality (Average = 1.00): 1.83

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.380
Length to Beam Ratio: 11.11 : 1
'Natural speed' for length: 20.84 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19.69 ft / 6.00 m
- Forecastle (15 %): 16.40 ft / 5.00 m
- Mid (50 %): 14.76 ft / 4.50 m
- Quarterdeck (15 %): 14.76 ft / 4.50 m
- Stern: 14.76 ft / 4.50 m
- Average freeboard: 15.49 ft / 4.72 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 139.5 %
- Above water (accommodation/working, high = better): 104.9 %
Waterplane Area: 6,128 Square feet or 569 Square metres
Displacement factor (Displacement / loading): 110 %
Structure weight / hull surface area: 29 lbs/sq ft or 143 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 3.40
- Overall: 0.60
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Sorry - the L:B ratio is larger than allowed by the Gentlemen's Rules - 11:1 is the max for vessels of 8,000 tons or less.

Always something... Although that dates back a couple of iterations.


AS46E, Nordmark ASW Sloop laid down 1946

Displacement:
1,029 t light; 1,105 t standard; 1,291 t normal; 1,439 t full load

Dimensions: Length overall / water x beam x draught
334.84 ft / 328.08 ft x 29.86 ft x 12.14 ft (normal load)
102.06 m / 100.00 m x 9.10 m x 3.70 m

Armament:
4 - 3.54" / 90.0 mm guns in single mounts, 22.24lbs / 10.09kg shells, 1946 Model
Automatic rapid fire guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, all forward
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, all aft
Weight of broadside 105 lbs / 47 kg
Shells per gun, main battery: 800
4 - 24.0" / 610 mm above water torpedoes

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 18,681 shp / 13,936 Kw = 30.00 kts
Range 6,000nm at 15.00 kts
Bunker at max displacement = 334 tons

Complement:
106 - 139

Cost:
£0.810 million / $3.238 million

Distribution of weights at normal displacement:
Armament: 15 tons, 1.2 %
Machinery: 467 tons, 36.1 %
Hull, fittings & equipment: 432 tons, 33.4 %
Fuel, ammunition & stores: 262 tons, 20.3 %
Miscellaneous weights: 115 tons, 8.9 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
675 lbs / 306 Kg = 30.3 x 3.5 " / 90 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.17
Metacentric height 1.1 ft / 0.3 m
Roll period: 12.0 seconds
Steadiness - As gun platform (Average = 50 %): 81 %
- Recoil effect (Restricted arc if above 1.00): 0.40
Seaboat quality (Average = 1.00): 1.80

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.380
Length to Beam Ratio: 10.99 : 1
'Natural speed' for length: 20.85 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 45
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19.69 ft / 6.00 m
- Forecastle (15 %): 16.40 ft / 5.00 m
- Mid (50 %): 14.76 ft / 4.50 m
- Quarterdeck (15 %): 14.76 ft / 4.50 m
- Stern: 14.76 ft / 4.50 m
- Average freeboard: 15.49 ft / 4.72 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 139.2 %
- Above water (accommodation/working, high = better): 106.8 %
Waterplane Area: 6,196 Square feet or 576 Square metres
Displacement factor (Displacement / loading): 110 %
Structure weight / hull surface area: 30 lbs/sq ft or 145 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 3.35
- Overall: 0.61
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

*pause*

*squint at mount descriptions*

...And I am a derp.


AS46F, Nordmark ASW Sloop laid down 1946

Displacement:
1,055 t light; 1,132 t standard; 1,319 t normal; 1,469 t full load

Dimensions: Length overall / water x beam x draught
334.84 ft / 328.08 ft x 30.51 ft x 12.14 ft (normal load)
102.06 m / 100.00 m x 9.30 m x 3.70 m

Armament:
4 - 3.54" / 90.0 mm guns in single mounts, 22.24lbs / 10.09kg shells, 1946 Model
Automatic rapid fire guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, all forward
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, all aft
Weight of broadside 105 lbs / 47 kg
Shells per gun, main battery: 800
4 - 24.0" / 610 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.98" / 25 mm 0.39" / 10 mm -
2nd: 0.59" / 15 mm 0.39" / 10 mm -
3rd: 0.59" / 15 mm 0.39" / 10 mm -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 18,933 shp / 14,124 Kw = 30.00 kts
Range 6,000nm at 15.00 kts
Bunker at max displacement = 338 tons

Complement:
109 - 142

Cost:
£0.822 million / $3.289 million

Distribution of weights at normal displacement:
Armament: 15 tons, 1.2 %
Armour: 9 tons, 0.7 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 9 tons, 0.7 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 473 tons, 35.8 %
Hull, fittings & equipment: 432 tons, 32.8 %
Fuel, ammunition & stores: 265 tons, 20.1 %
Miscellaneous weights: 125 tons, 9.5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
687 lbs / 312 Kg = 30.9 x 3.5 " / 90 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.17
Metacentric height 1.1 ft / 0.3 m
Roll period: 12.1 seconds
Steadiness - As gun platform (Average = 50 %): 78 %
- Recoil effect (Restricted arc if above 1.00): 0.34
Seaboat quality (Average = 1.00): 1.72

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.380
Length to Beam Ratio: 10.75 : 1
'Natural speed' for length: 20.89 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 45
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19.69 ft / 6.00 m
- Forecastle (15 %): 16.40 ft / 5.00 m
- Mid (50 %): 14.76 ft / 4.50 m
- Quarterdeck (15 %): 14.76 ft / 4.50 m
- Stern: 14.76 ft / 4.50 m
- Average freeboard: 15.49 ft / 4.72 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 138.6 %
- Above water (accommodation/working, high = better): 107.5 %
Waterplane Area: 6,333 Square feet or 588 Square metres
Displacement factor (Displacement / loading): 110 %
Structure weight / hull surface area: 30 lbs/sq ft or 146 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 3.14
- Overall: 0.60
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

5 tons general search radar
2 tons navigational radar
3 tons fire control radar
3 tons fire control computers
4 tons electronic-suite generators

9 tons sonar
40 tons 80x depth charges and launching racks
20 tons 20x depth charges and forward-throwing launchers

24 tons torpedoes and support equipment w/ 1 reload

15 tons unplanned weight allowance

Not a bad design. Getting good seakeeping does rely on black magic and a lot of tinkering!

30kts seems fast for a sloop, generally a sloop would be for escorting convoys and peacetime flag showing. But I guess for fleet escorting, the speed would be higher, however something more optimal for commerce protection might be economical too (saying that my 22kts sloops still come out at around 1,100 tons!).

I'm not in love with it, but cutting the speed down and the mine layout in half gives... this:



Enter ship name, Enter country Enter ship type laid down 1946

Displacement:
535 t light; 600 t standard; 673 t normal; 731 t full load

Dimensions: Length overall / water x beam x draught
216.73 ft / 213.25 ft x 29.53 ft x 9.84 ft (normal load)
66.06 m / 65.00 m x 9.00 m x 3.00 m

Armament:
4 - 3.54" / 90.0 mm guns in single mounts, 22.24lbs / 10.09kg shells, 1946 Model
Automatic rapid fire guns in deck mounts with hoists
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, all forward
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, all aft
Weight of broadside 105 lbs / 47 kg
Shells per gun, main battery: 800
4 - 24.0" / 610 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.59" / 15 mm 0.39" / 10 mm -
2nd: 0.59" / 15 mm 0.39" / 10 mm -
3rd: 0.59" / 15 mm 0.39" / 10 mm -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 5,138 shp / 3,833 Kw = 23.00 kts
Range 6,000nm at 12.00 kts
Bunker at max displacement = 132 tons

Complement:
65 - 85

Cost:
£0.351 million / $1.406 million

Distribution of weights at normal displacement:
Armament: 15 tons, 2.3 %
Armour: 8 tons, 1.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 8 tons, 1.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 128 tons, 19.1 %
Hull, fittings & equipment: 289 tons, 42.9 %
Fuel, ammunition & stores: 137 tons, 20.4 %
Miscellaneous weights: 95 tons, 14.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
893 lbs / 405 Kg = 40.1 x 3.5 " / 90 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.12
Metacentric height 1.0 ft / 0.3 m
Roll period: 12.4 seconds
Steadiness - As gun platform (Average = 50 %): 46 %
- Recoil effect (Restricted arc if above 1.00): 0.42
Seaboat quality (Average = 1.00): 1.84

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.380
Length to Beam Ratio: 7.22 : 1
'Natural speed' for length: 17.47 kts
Power going to wave formation at top speed: 64 %
Trim (Max stability = 0, Max steadiness = 100): 23
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: 19.69 ft / 6.00 m
- Forecastle (15 %): 16.40 ft / 5.00 m
- Mid (50 %): 16.40 ft / 5.00 m
- Quarterdeck (15 %): 16.40 ft / 5.00 m
- Stern: 16.40 ft / 5.00 m
- Average freeboard: 16.60 ft / 5.06 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 101.5 %
- Above water (accommodation/working, high = better): 81.9 %
Waterplane Area: 3,983 Square feet or 370 Square metres
Displacement factor (Displacement / loading): 140 %
Structure weight / hull surface area: 30 lbs/sq ft or 144 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 10.72
- Overall: 0.68
Caution: Hull subject to strain in open-sea
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is cramped
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Your latest design violates Point One of the Gentlemen's rules - only small fast combatants, < 6,000 tons, speed > 24 knots, can have a composite strength of less than 1.00.

The armament you propose is far too much for the hull as well.

Just as well it's a throwaway pencil sketch, then, rather than an actual proposal.

Consider something along these lines...

-----

TBD, TBD Ocean Escort laid down 1946

Displacement:
750 t light; 827 t standard; 972 t normal; 1,088 t full load

Dimensions: Length overall / water x beam x draught
254.10 ft / 246.06 ft x 33.14 ft x 9.84 ft (normal load)
77.45 m / 75.00 m x 10.10 m x 3.00 m

Armament:
4 - 3.54" / 90.0 mm guns (2x2 guns), 22.24lbs / 10.09kg shells, 1946 Model
Automatic rapid fire guns in deck mounts with hoists
on centreline ends, evenly spread
8 - 1.57" / 40.0 mm guns (2x4 guns), 1.95lbs / 0.89kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on centreline ends, evenly spread, all raised mounts
4 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 106 lbs / 48 kg
Shells per gun, main battery: 900

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.98" / 25 mm 0.59" / 15 mm 0.98" / 25 mm
2nd: 0.59" / 15 mm 0.59" / 15 mm -
3rd: 0.39" / 10 mm - -

- Conning tower: 0.98" / 25 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 4,308 shp / 3,214 Kw = 20.00 kts
Range 5,000nm at 15.00 kts
Bunker at max displacement = 260 tons

Complement:
86 - 113

Cost:
£0.385 million / $1.539 million

Distribution of weights at normal displacement:
Armament: 15 tons, 1.6 %
Armour: 12 tons, 1.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 10 tons, 1.0 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.2 %
Machinery: 108 tons, 11.1 %
Hull, fittings & equipment: 495 tons, 50.9 %
Fuel, ammunition & stores: 222 tons, 22.9 %
Miscellaneous weights: 120 tons, 12.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
2,503 lbs / 1,136 Kg = 112.6 x 3.5 " / 90 mm shells or 1.1 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 1.1 ft / 0.3 m
Roll period: 13.0 seconds
Steadiness - As gun platform (Average = 50 %): 68 %
- Recoil effect (Restricted arc if above 1.00): 0.28
Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.424
Length to Beam Ratio: 7.43 : 1
'Natural speed' for length: 15.69 kts
Power going to wave formation at top speed: 54 %
Trim (Max stability = 0, Max steadiness = 100): 34
Bow angle (Positive = bow angles forward): 18.00 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 %): 18.04 ft / 5.50 m
- Mid (50 %): 14.76 ft / 4.50 m
- Quarterdeck (20 %): 14.76 ft / 4.50 m
- Stern: 14.76 ft / 4.50 m
- Average freeboard: 16.04 ft / 4.89 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 67.8 %
- Above water (accommodation/working, high = better): 175.9 %
Waterplane Area: 5,097 Square feet or 474 Square metres
Displacement factor (Displacement / loading): 207 %
Structure weight / hull surface area: 46 lbs/sq ft or 224 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.80
- Longitudinal: 7.62
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Similar offensive and mission capabilities, three hundred tons lighter...

...and ten knots slower.

I don't think it makes sense.

I don't think it makes sense for Nordmark, which is at peace and has a decent amount of cash to spend on something more flexible and capable of maybe making even a heavy raider like a CA think better of the chance of eating a torpedo, and I don't think it makes sense as a war-emergency-as-many-hulls-as-can-be subchaser that'll serve as a beater for a convoy's actual protection.

That'd look more like this:



Enter ship name, Enter country Enter ship type laid down 1946

Displacement:
353 t light; 375 t standard; 408 t normal; 435 t full load

Dimensions: Length overall / water x beam x draught
164.04 ft / 164.04 ft x 22.97 ft x 9.84 ft (normal load)
50.00 m / 50.00 m x 7.00 m x 3.00 m

Armament:
1 - 3.54" / 90.0 mm guns in single mounts, 22.24lbs / 10.09kg shells, 1946 Model
Automatic rapid fire gun in a deck mount with hoist
on centreline forward
6 - 1.57" / 40.0 mm guns (3x2 guns), 1.95lbs / 0.89kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on centreline, evenly spread, 2 raised mounts
Weight of broadside 34 lbs / 15 kg
Shells per gun, main battery: 600

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 1 shaft, 3,672 shp / 2,739 Kw = 21.00 kts
Range 5,000nm at 10.00 kts
Bunker at max displacement = 60 tons

Complement:
44 - 58

Cost:
£0.207 million / $0.829 million

Distribution of weights at normal displacement:
Armament: 5 tons, 1.2 %
Machinery: 92 tons, 22.5 %
Hull, fittings & equipment: 206 tons, 50.5 %
Fuel, ammunition & stores: 55 tons, 13.5 %
Miscellaneous weights: 50 tons, 12.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
655 lbs / 297 Kg = 29.4 x 3.5 " / 90 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.08
Metacentric height 0.6 ft / 0.2 m
Roll period: 12.0 seconds
Steadiness - As gun platform (Average = 50 %): 42 %
- Recoil effect (Restricted arc if above 1.00): 0.25
Seaboat quality (Average = 1.00): 1.68

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.385
Length to Beam Ratio: 7.14 : 1
'Natural speed' for length: 12.81 kts
Power going to wave formation at top speed: 66 %
Trim (Max stability = 0, Max steadiness = 100): 21
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: 16.40 ft / 5.00 m
- Forecastle (15 %): 16.40 ft / 5.00 m
- Mid (60 %): 16.40 ft / 5.00 m (8.20 ft / 2.50 m aft of break)
- Quarterdeck (15 %): 8.20 ft / 2.50 m
- Stern: 8.20 ft / 2.50 m
- Average freeboard: 13.12 ft / 4.00 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 98.5 %
- Above water (accommodation/working, high = better): 126.7 %
Waterplane Area: 2,173 Square feet or 202 Square metres
Displacement factor (Displacement / loading): 150 %
Structure weight / hull surface area: 34 lbs/sq ft or 164 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.73
- Longitudinal: 16.41
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Quoted

I don't think it makes sense for Nordmark, which is at peace and has a decent amount of cash to spend on something more flexible and capable of maybe making even a heavy raider like a CA think better of the chance of eating a torpedo, and I don't think it makes sense as a war-emergency-as-many-hulls-as-can-be subchaser that'll serve as a beater for a convoy's actual protection.

Given the stand off range of a heavy cruiser's main armament, I cannot see why it would even bother to come into torpedo range; and tin-can death rides a'la Leyte Gulf not what one plans for. However, it's your choice; I merely wanted to offer suggestions.

Best defense against a heavy raider is an equivalent ship. Subchasers like the one above are very useful - but for coastal convoys in areas like the Baltic, the North Sea, the Gulf of Finland, etc.

Its a tricky choice. I'd say a 23-25kts sloop would suffice for ASW, since you don't need high speed for that. For AA protection its helpful to keep up with what you are escorting. I'm wondering how often the Nordish fleet in wartime would be dashing around at top speed? For normal transits and re-siting probably not, but given hit and run raids from fjords and things, most combat would be high speed dashes I would think. I'd be interested to hear your opinions on this.

My thoughts had been that Nordmark was unlikely to be the 'heavy' side of any conflict in the North Atlantic, and unlikely to involve itself in any conflicts outside that region unless as part of an all up multinational allied deployment. The urgent need to keep lines from the mainland to the insular territories - Iceland, Greenland, and Vinland (Newfoundland) - open is going to press the fleet to operate 'actively' rather than complicating the lives of the enemy as a fleet-in-being.

But if you're forced to go out and pick a fight as the smaller combatant, you need to be the more agile one, able to pick fights on your terms by evading anything too big to beat. Which means operating at high 'cruising' speeds... Hmm. A class of fast oilers and supply ships in '47? Enh; probably premature to plan that far ahead at this stage.