WesWorld

The CNDO presents the requirements for the Coast Guard & Rescue vessel (CGRV).

Coast Guard & Rescue Vessel:

Type 0 slip => Length < 70m / Beam: ~ 15m / Draft: ~ 7m
Speed: ~ 20kn
Engine: 15 000 kw

a lot of Misc. Weight (enough space for first aid and medical supplies)
very high seaworthy (~1,9 or more)
ice breaking ability

Armour: none / may be only bridge armour

Weapon: 1 Heavy AA or Dual-purpose + may be some MG's


The chinese design will be presented very soon.

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Feel free to discuss
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I'm still not very comfortable w/ metric, and I realize this is in SS3, but here's my first crack at it.

CGRV-1, China Coast Guard Rescue Ship laid down 1936

Displacement:
2,237 t light; 2,302 t standard; 2,617 t normal; 2,869 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(229.66 ft / 213.25 ft) x 49.21 ft x (22.97 / 24.35 ft)
(70.00 m / 65.00 m) x 15.00 m x (7.00 / 7.42 m)

Armament:
1 - 5.12" / 130 mm 45.0 cal gun - 67.61lbs / 30.67kg shells, 300 per gun
Dual purpose gun in deck mount, 1936 Model
1 x Single mount on centreline, forward deck forward
2 - 1.46" / 37.0 mm 55.0 cal guns - 1.65lbs / 0.75kg shells, 500 per gun
Anti-air guns in deck mounts, 1936 Model
2 x Single mounts on sides, forward deck aft
3 - 0.35" / 8.8 mm 76.0 cal guns - 0.02lbs / 0.01kg shells, 150 per gun
Machine guns in deck mounts, 1936 Model
2 x Single mounts on sides, aft deck forward
1 x Single mount on centreline, aft deck centre
Weight of broadside 71 lbs / 32 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Ends: 5.91" / 150 mm 16.40 ft / 5.00 m 26.25 ft / 8.00 m
196.85 ft / 60.00 m Unarmoured ends

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.97" / 50 mm - -
2nd: 0.98" / 25 mm - -

- Box over machinery & magazines: 0.98" / 25 mm

- Conning towers: Forward 1.97" / 50 mm, Aft 0.00" / 0 mm

Machinery:
Diesel Internal combustion generators,
Electric motors, 2 shafts, 9,111 shp / 6,797 Kw = 20.00 kts
Range 5,000nm at 15.00 kts
Bunker at max displacement = 567 tons

Complement:
182 - 237

Cost:
£0.620 million / $2.481 million

Distribution of weights at normal displacement:
Armament: 14 tons, 0.5 %
Armour: 175 tons, 6.7 %
- Belts: 94 tons, 3.6 %
- Armament: 7 tons, 0.3 %
- Armour Deck: 66 tons, 2.5 %
- Conning Tower: 8 tons, 0.3 %
Machinery: 256 tons, 9.8 %
Hull, fittings & equipment: 907 tons, 34.7 %
Fuel, ammunition & stores: 380 tons, 14.5 %
Miscellaneous weights: 885 tons, 33.8 %
- Hull below water: 885 tons

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
6,374 lbs / 2,891 Kg = 95.1 x 5.1 " / 130 mm shells or 1.5 torpedoes
Stability (Unstable if below 1.00): 1.70
Metacentric height 4.1 ft / 1.3 m
Roll period: 10.2 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.02
Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:
Hull has a flush deck,
a ram bow and a round stern
Block coefficient (normal/deep): 0.380 / 0.393
Length to Beam Ratio: 4.33 : 1
'Natural speed' for length: 14.60 kts
Power going to wave formation at top speed: 65 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 18.40 degrees
Stern overhang: 6.56 ft / 2.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 29.53 ft / 9.00 m, 26.25 ft / 8.00 m
- Forward deck: 30.00 %, 26.25 ft / 8.00 m, 22.97 ft / 7.00 m
- Aft deck: 35.00 %, 22.97 ft / 7.00 m, 22.97 ft / 7.00 m
- Quarter deck: 15.00 %, 22.97 ft / 7.00 m, 22.97 ft / 7.00 m
- Average freeboard: 24.38 ft / 7.43 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 70.9 %
- Above water (accommodation/working, high = better): 158.3 %
Waterplane Area: 6,375 Square feet or 592 Square metres
Displacement factor (Displacement / loading): 163 %
Structure weight / hull surface area: 60 lbs/sq ft or 294 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.72
- Longitudinal: 20.67
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

End belt is icebreaker plating on ram and bow
Misc weight for heating/cooling equipment, bunks, medical supplies, rescue gear, blankest/dry clothes, lifejackets, and inflatable rafts.

Why does China need an icebreaker? Ah who cares...


Australia can offer this design. Already in service with the RAN.

HMAS Discovery, Australia Antartic Research Vessel laid down 1931

Displacement:
1,714 t light; 1,771 t standard; 2,634 t normal; 3,325 t full load

Dimensions: Length overall / water x beam x draught
320.00 ft / 320.00 ft x 42.00 ft x 14.00 ft (normal load)
97.54 m / 97.54 m x 12.80 m x 4.27 m

Armament:
1 - 4.70" / 119 mm guns in single mounts, 51.91lbs / 23.55kg shells, 1931 Model
Breech loading gun in deck mount
on centreline forward
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1931 Model
Breech loading guns in deck mounts
on centreline, evenly spread, 1 raised mount
8 - 0.79" / 20.0 mm guns (4x2 guns), 0.24lbs / 0.11kg shells, 1931 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 62 lbs / 28 kg
Shells per gun, main battery: 120

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 1.20" / 30 mm 320.00 ft / 97.54 m 9.00 ft / 2.74 m
Ends: Unarmoured
Main Belt covers 154 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.20" / 30 mm - -

Machinery:
Oil fired boilers, steam turbines,
Electric cruising motors plus geared drives, 2 shafts, 8,996 shp / 6,711 Kw = 21.00 kts
Range 15,000nm at 15.00 kts
Bunker at max displacement = 1,553 tons

Complement:
183 - 239

Cost:
£0.454 million / $1.817 million

Distribution of weights at normal displacement:
Armament: 8 tons, 0.3 %
Armour: 131 tons, 5.0 %
- Belts: 128 tons, 4.9 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 3 tons, 0.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 269 tons, 10.2 %
Hull, fittings & equipment: 1,066 tons, 40.5 %
Fuel, ammunition & stores: 920 tons, 34.9 %
Miscellaneous weights: 240 tons, 9.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
7,599 lbs / 3,447 Kg = 146.4 x 4.7 " / 119 mm shells or 2.3 torpedoes
Stability (Unstable if below 1.00): 1.31
Metacentric height 2.2 ft / 0.7 m
Roll period: 11.9 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.02
Seaboat quality (Average = 1.00): 1.54

Hull form characteristics:
Hull has low quarterdeck
Block coefficient: 0.490
Length to Beam Ratio: 7.62 : 1
'Natural speed' for length: 17.89 kts
Power going to wave formation at top speed: 53 %
Trim (Max stability = 0, Max steadiness = 100): 46
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: 15.00 ft / 4.57 m
- Forecastle (20 %): 14.00 ft / 4.27 m
- Mid (50 %): 14.00 ft / 4.27 m
- Quarterdeck (15 %): 12.00 ft / 3.66 m (14.00 ft / 4.27 m before break)
- Stern: 12.00 ft / 3.66 m
- Average freeboard: 13.78 ft / 4.20 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 46.6 %
- Above water (accommodation/working, high = better): 129.3 %
Waterplane Area: 8,874 Square feet or 824 Square metres
Displacement factor (Displacement / loading): 271 %
Structure weight / hull surface area: 75 lbs/sq ft or 366 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.25
- Longitudinal: 2.59
- Overall: 1.35
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather


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Also Australia could be willing to sell this class of 4:

Polar Bear
Polar Light
Snow-White
Snow Flake

Polar Bear class, Australia (ex-SAE) Artic Sloop laid down 1911 (reffited 1921)

Displacement:
822 t light; 850 t standard; 1.246 t normal; 1.557 t full load
Loading submergence 132 tons/feet

Dimensions:
221,46 ft x 31,17 ft x 11,48 ft (normal load)
67,50 m x 9,50 m x 3,50 m

Armament:
2 - 3,46" / 88 mm guns
4 - 0,79" / 20 mm guns
Weight of broadside 43 lbs / 19 kg

Armour:
Belt 0,39" / 10 mm, end belts 0,98" / 25 mm
Belts cover 67% of normal area
Main gun shields 0,98" / 25 mm, Light gun shields 0,39" / 10 mm

Machinery:
Coal fired boilers, complex reciprocating steam engines,
Direct drive, 2 shafts, 2.011 ihp / 1.500 Kw = 15,49 kts
Range 11.800nm at 10,00 kts

Complement:
104 - 136

Cost:
£0,052 million / $0,208 million

Distribution of weights at normal displacement:
Armament: 5 tons, 0,4%
Armour: 26 tons, 2,1%
Belts: 24 tons, 1,9%, Armament: 2 tons, 0,2%, Armour Deck: 0 tons, 0,0%
Conning Tower: 0 tons, 0,0%, Torpedo bulkhead: 0 tons, 0,0%
Machinery: 134 tons, 10,7%
Hull, fittings & equipment: 357 tons, 28,7%
Fuel, ammunition & stores: 424 tons, 34,0%
Miscellaneous weights: 300 tons, 24,1%

Metacentric height 1,1

Remarks:
Hull space for machinery, storage & compartmentation is excellent
Room for accommodation & workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable and able to fight her guns in the heaviest weather

Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1,16
Shellfire needed to sink: 2.279 lbs / 1.034 Kg = 109,6 x 3,5 " / 88 mm shells
(Approx weight of penetrating shell hits needed to sink ship excluding critical hits)
Torpedoes needed to sink: 1,1
(Approx number of typical torpedo hits needed to sink ship)
Relative steadiness as gun platform: 74 %
(Average = 50 %)
Relative rocking effect from firing to beam: 0,05
Relative quality as seaboat: 2,00

Hull form characteristics:
Block coefficient: 0,550
Sharpness coefficient: 0,39
Hull speed coefficient 'M': 6,29
'Natural speed' for length: 14,88 kts
Power going to wave formation at top speed: 49 %
Trim: 37
(Maximise stabilty/flotation = 0, Maximise steadiness/seakeeping = 100)

Estimated hull characteristics & strength:
Underwater volume absorbed by magazines and engineering spaces: 65,2%
Relative accommodation and working space: 97,3%
(Average = 100%)
Displacement factor: 196%
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0,96
(Structure weight / hull surface area: 45 lbs / square foot or 219 Kg / square metre)
Relative longitudinal hull strength: 2,53
(for 11,48 ft / 3,50 m average freeboard, freeboard adjustment 1,50 ft)
Relative composite hull strength: 1,05

The 7m draught is rather excessive for a ship of this size.

China thanks Australia for the offers to purchase the vessels. The offer for the purchase of 4 ships of the polar bear class is very tempting, because these vessels could be used immediately.

About the Discovery design:
The ships didn't need such a great range, it could be reduced under 4000nm and the free tonnage could be put in the misc weight

And so icebreakers need lots of fuel. You must run the power plant at full power, in order to make 2-3 knots through ice thick enough to need an icebreaker. Running at full power increases fuel consumption a LOT.

The icebreaking capability is just a nice to have.


Through the merging of functions, China tried to reduce the diversity of its fleet to a minimum. Perhaps China should look for a pure icebreaker.

After lengthy discussions, this project was canceled by the CNDO.

The coast guard task will be made by the ships of the Dagu class.