WesWorld

How do you sim icebreakers?

With all the action in Penguinstan Im going to need some polar research vessels to keep an eye on my back yard.

Basically you use the belt armour and torpedo bulkhead to sim the extra-strength hull; using Pacifica for an example:

Quoted

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2.95" / 75 mm 328.08 ft / 100.00 m 11.29 ft / 3.44 m
Ends: 3.94" / 100 mm 170.60 ft / 52.00 m 11.29 ft / 3.44 m
Main Belt covers 101 % of normal length

- Torpedo Bulkhead:
1.97" / 50 mm 498.69 ft / 152.00 m 12.60 ft / 3.84 m

You'll also want extra-long range, as you'll be using a lot of fuel plowing through the ice - 15000nm@15knt is about the bare minimum.

Also include a lot of misc. weight for "winterisation" and the science equipment.

Finally, keep the hull strength (in all categories) 1.40 or up.

But the Naval Treaty has some provisions that apply:

G. VESSELS NOT SUBJECT TO LIMITATIONS IN NUMBER AND/OR TONNAGE



I.



Subject to any special agreements which may submit them to

limitation, the following vessels are exempt from limitation:



(a) Naval surface combatant vessels of 600 tons (610 metric tons)

standard displacement and under;





(b) Naval surface combatant vessels exceeding 600 tons (610 metric

tons), but not exceeding 2,000 tons (2,032 metric tons) standard

displacement, provided they have none of the following

characteristics:

(1) Mount a gun above 5.1 inch (130 mm) calibre;

(2) Mount more than eight guns above 3 inch (76 mm) calibre;

(3) Are designed or fitted to launch torpedoes;

(4) Are designed for a speed greater than 24 knots.

(5) Are fitted to receive aircraft on board from the air.





(c) Naval surface vessels not specifically built as fighting ships

which are employed on fleet duties or as troop transports or in

some other way than as fighting ships, provided they have none of

the following characteristics:

(1) Mount a gun above 6 inch (153 mm) calibre;

(2) Mount more than four guns above 3 inch (76 mm) calibre;

(3) Are designed or fitted to launch torpedoes:

(4) Are designed for a speed greater than 20 knots;

(5) Are protected by armour plate on the hull;

(6) Are designed or fitted to launch mines;

(7) Are fitted to receive aircraft on board from the air;

( Mount more than one aircraft-launching apparatus on the

centre line; or two, one on each broadside;

(9) If fitted with any means of launching aircraft into the air,

are designed or adapted to operate at sea more than ten

aircraft.





II.



Following special consideration, icebreakers large enough to be

counted in subcategory (c) in Part 3, Chapter F, Article I (c) above,

shall be counted in that subcategory despite having a hull-

construction that would otherwise cause the icebreaker to be armoured

on the hull, provided that (a) the total number of such icebreakers

shall not exceed two thirds of the maximum number of capital ships

allowed to each nation, rounded down, and (b) that these vessels in

all other particulars do not exceed the limitations pursuant to ships

classed under Part 3, Chapter F, Article I (c).

The other option would be to classify it as a cruiser of some kind. I know of a few cruisers that were used as survey vessels during this time period. And while they might not be as useful as a regular cruiser, they could still be useful in the southern most seas should Australia need to watch its back for ships coming from Penguinstan and/or the Japanese bases.

So... what you are suggesting is to waste some cruiser tonnage to construct some slow arctic cruiser that can also act as an escort cruiser and which is unable to blow the Filipino Battlecruiser out of the water...
Hmmm....

Much better to use CDS tonnage, like so:

Filipino Bacolod-class Escort Cruiser for Icebreakers laid down 1929

Displacement:
3,962 t light; 4,175 t standard; 4,798 t normal; 5,297 t full load

Dimensions: Length overall / water x beam x draught
327.46 ft / 311.68 ft x 54.79 ft x 18.04 ft (normal load)
99.81 m / 95.00 m x 16.70 m x 5.50 m

Armament:
6 - 6.10" / 155 mm guns (2x3 guns), 120.00lbs / 54.43kg shells, 1929 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread
4 - 3.94" / 100 mm guns (2x2 guns), 32.00lbs / 14.51kg shells, 1929 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread, all raised mounts - superfiring
4 - 3.94" / 100 mm guns (2x2 guns), 32.00lbs / 14.51kg shells, 1929 Model
Dual purpose guns in deck mounts with hoists
on side, all amidships
6 - 0.98" / 25.0 mm guns (2x3 guns), 0.57lbs / 0.26kg shells, 1929 Model
Anti-aircraft guns in deck mounts
on side, all aft, all raised mounts
8 - 0.54" / 13.7 mm guns (2x4 guns), 0.11lbs / 0.05kg shells, 1929 Model
Anti-aircraft guns in deck mounts
on side, all forward, all raised mounts

Weight of broadside 980 lbs / 445 kg
Shells per gun, main battery: 200

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4.72" / 120 mm 311.68 ft / 95.00 m 10.66 ft / 3.25 m
Upper: 0.98" / 25 mm 311.68 ft / 95.00 m 9.84 ft / 3.00 m
Main Belt covers 154 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 6.10" / 155 mm 3.94" / 100 mm 4.92" / 125 mm
2nd: 1.18" / 30 mm 0.59" / 15 mm 0.98" / 25 mm
3rd: 1.18" / 30 mm 0.59" / 15 mm 0.98" / 25 mm
4th: 0.59" / 15 mm - -
5th: 0.59" / 15 mm - -

- Armour deck: 3.15" / 80 mm, Conning tower: 3.15" / 80 mm

Machinery:
Diesel Internal combustion generators,
Electric motors, 2 shafts, 12,500 shp / 9,325 Kw = 20.40 kts
Range 12,500nm at 12.00 kts (Bunkerage = 1,122 tons)

Complement:
287 - 374

Cost:
£1.160 million / $4.640 million

Distribution of weights at normal displacement:
Armament: 116 tons, 2.4 %
Armour: 1,629 tons, 33.9 %
- Belts: 693 tons, 14.4 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 226 tons, 4.7 %
- Armour Deck: 691 tons, 14.4 %
- Conning Tower: 19 tons, 0.4 %
Machinery: 384 tons, 8.0 %
Hull, fittings & equipment: 1,783 tons, 37.2 %
Fuel, ammunition & stores: 836 tons, 17.4 %
Miscellaneous weights: 50 tons, 1.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
11,199 lbs / 5,080 Kg = 98.6 x 6.1 " / 155 mm shells or 2.8 torpedoes
Stability (Unstable if below 1.00): 1.13
Metacentric height 2.6 ft / 0.8 m
Roll period: 14.4 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.36
Seaboat quality (Average = 1.00): 1.35

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.545
Length to Beam Ratio: 5.69 : 1
'Natural speed' for length: 17.65 kts
Power going to wave formation at top speed: 58 %
Trim (Max stability = 0, Max steadiness = 100): 52
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 21.65 ft / 6.60 m
- Forecastle (18 %): 18.04 ft / 5.50 m
- Mid (50 %): 14.76 ft / 4.50 m
- Quarterdeck (18 %): 14.76 ft / 4.50 m
- Stern: 14.76 ft / 4.50 m
- Average freeboard: 16.12 ft / 4.91 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 47.8 %
- Above water (accommodation/working, high = better): 122.7 %
Waterplane Area: 11,862 Square feet or 1,102 Square metres
Displacement factor (Displacement / loading): 142 %
Structure weight / hull surface area: 98 lbs/sq ft or 478 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.00
- Longitudinal: 3.55
- Overall: 1.14
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
Good seaboat, rides out heavy weather easily

25t special underwater protection
25t winterization

Something like this? I have my own Antartic BB in the works too.

HMAS Shackleton, Australia, Polar Research vessel, laid down 1929

Displacement:
2,424 t light; 2,516 t standard; 4,125 t normal; 5,412 t full load

Dimensions: Length overall / water x beam x draught
320.00 ft / 320.00 ft x 47.00 ft x 15.00 ft (normal load)
97.54 m / 97.54 m x 14.33 m x 4.57 m

Armament:
1 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1929 Model
Breech loading gun in deck mount
on centreline forward
4 - 1.57" / 40.0 mm guns in single mounts, 1.95lbs / 0.88kg shells, 1929 Model
Breech loading guns in deck mounts
on side, all amidships
4 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1929 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 117 lbs / 53 kg
Shells per gun, main battery: 150

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 1.20" / 30 mm 200.00 ft / 60.96 m 9.00 ft / 2.74 m
Ends: 2.40" / 61 mm 120.00 ft / 36.58 m 9.00 ft / 2.74 m
Main Belt covers 96 % of normal length

- Torpedo Bulkhead:
0.50" / 13 mm 200.00 ft / 60.96 m 15.00 ft / 4.57 m

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

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 10,585 shp / 7,896 Kw = 20.00 kts
Range 20,000nm at 15.00 kts
Bunker at max displacement = 2,896 tons

Complement:
256 - 334

Cost:
£0.570 million / $2.282 million

Distribution of weights at normal displacement:
Armament: 15 tons, 0.4 %
Armour: 251 tons, 6.1 %
- Belts: 191 tons, 4.6 %
- Torpedo bulkhead: 56 tons, 1.3 %
- Armament: 4 tons, 0.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 325 tons, 7.9 %
Hull, fittings & equipment: 1,543 tons, 37.4 %
Fuel, ammunition & stores: 1,702 tons, 41.2 %
Miscellaneous weights: 290 tons, 7.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
14,083 lbs / 6,388 Kg = 130.4 x 6.0 " / 152 mm shells or 4.1 torpedoes
Stability (Unstable if below 1.00): 1.37
Metacentric height 2.8 ft / 0.9 m
Roll period: 11.8 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.03
Seaboat quality (Average = 1.00): 1.36

Hull form characteristics:
Hull has low quarterdeck
Block coefficient: 0.640
Length to Beam Ratio: 6.81 : 1
'Natural speed' for length: 17.89 kts
Power going to wave formation at top speed: 56 %
Trim (Max stability = 0, Max steadiness = 100): 52
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: 20.00 ft / 6.10 m
- Forecastle (20 %): 15.00 ft / 4.57 m
- Mid (50 %): 15.00 ft / 4.57 m
- Quarterdeck (15 %): 12.00 ft / 3.66 m (15.00 ft / 4.57 m before break)
- Stern: 12.00 ft / 3.66 m
- Average freeboard: 14.95 ft / 4.56 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 65.2 %
- Above water (accommodation/working, high = better): 127.4 %
Waterplane Area: 11,416 Square feet or 1,061 Square metres
Displacement factor (Displacement / loading): 316 %
Structure weight / hull surface area: 89 lbs/sq ft or 435 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.37
- Longitudinal: 2.60
- Overall: 1.46
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
Good seaboat, rides out heavy weather easily

My instinct tells me not enough armour - especially the torpedo bulkhead.

Yes, you should have protection against iceburgs and Fillipino torpedoes.

There is a real threat down there...
They even made a movie about it "March of the Penquins"
(I wonder if penquins do the goose step?)

Quoted

(I wonder if penquins do the goose step?)

Nazi penguins? Hopefully they arent Fillipino Exploding Penguins.

They're not going to be exaclly Icebreakers but research ships. So they dont need so much armor. Here is updated version with thicker TT bulkhead.

HMS Shackleton, Australia Polar Research Vessel laid down 1931

Displacement:
2,455 t light; 2,548 t standard; 4,125 t normal; 5,387 t full load

Dimensions: Length overall / water x beam x draught
320.00 ft / 320.00 ft x 47.00 ft x 15.00 ft (normal load)
97.54 m / 97.54 m x 14.33 m x 4.57 m

Armament:
1 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1931 Model
Breech loading gun in deck mount
on centreline forward
4 - 1.57" / 40.0 mm guns in single mounts, 1.95lbs / 0.89kg shells, 1931 Model
Breech loading guns in deck mounts
on side, all amidships
4 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1931 Model
Breech loading guns in deck mounts
on side, evenly spread
Weight of broadside 117 lbs / 53 kg
Shells per gun, main battery: 150

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 1.20" / 30 mm 200.00 ft / 60.96 m 9.00 ft / 2.74 m
Ends: 2.40" / 61 mm 120.00 ft / 36.58 m 9.00 ft / 2.74 m
Main Belt covers 96 % of normal length

- Torpedo Bulkhead:
0.79" / 20 mm 200.00 ft / 60.96 m 15.00 ft / 4.57 m

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

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 10,585 shp / 7,896 Kw = 20.00 kts
Range 20,000nm at 15.00 kts
Bunker at max displacement = 2,839 tons

Complement:
256 - 334

Cost:
£0.622 million / $2.487 million

Distribution of weights at normal displacement:
Armament: 15 tons, 0.4 %
Armour: 283 tons, 6.9 %
- Belts: 191 tons, 4.6 %
- Torpedo bulkhead: 88 tons, 2.1 %
- Armament: 4 tons, 0.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 317 tons, 7.7 %
Hull, fittings & equipment: 1,521 tons, 36.9 %
Fuel, ammunition & stores: 1,670 tons, 40.5 %
Miscellaneous weights: 320 tons, 7.8 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
13,982 lbs / 6,342 Kg = 129.5 x 6.0 " / 152 mm shells or 4.1 torpedoes
Stability (Unstable if below 1.00): 1.36
Metacentric height 2.8 ft / 0.8 m
Roll period: 11.9 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.03
Seaboat quality (Average = 1.00): 1.36

Hull form characteristics:
Hull has low quarterdeck
Block coefficient: 0.640
Length to Beam Ratio: 6.81 : 1
'Natural speed' for length: 17.89 kts
Power going to wave formation at top speed: 56 %
Trim (Max stability = 0, Max steadiness = 100): 52
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: 20.00 ft / 6.10 m
- Forecastle (20 %): 15.00 ft / 4.57 m
- Mid (50 %): 15.00 ft / 4.57 m
- Quarterdeck (15 %): 12.00 ft / 3.66 m (15.00 ft / 4.57 m before break)
- Stern: 12.00 ft / 3.66 m
- Average freeboard: 14.95 ft / 4.56 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 65.4 %
- Above water (accommodation/working, high = better): 127.4 %
Waterplane Area: 11,416 Square feet or 1,061 Square metres
Displacement factor (Displacement / loading): 305 %
Structure weight / hull surface area: 88 lbs/sq ft or 429 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.35
- Longitudinal: 2.57
- Overall: 1.44
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
Good seaboat, rides out heavy weather easily

Try a larger hull, 5000 tons should give you plenty of room for a thicker torpedo bulkhead (40 to 50mm) and give her the punch she needs to smash ice.

Fox:

That design is entirely too normal. I insist you add more armor and more guns. And make it bigger while you're at it.

In our world many navies have icebreakers and at one point they were heavily armed.
But most had only self-defense weapons.
Was there ever a real threat?
Ships of this type should have the capacity to embark at least 2 aircraft and have at least 1 catapult - you need aerial observation to stay safe from the ice and reach other ships that are ice-bound.
From stories I have heard from some Coast Guard people in the past:
Icebreakers in particular have rounded hulls with no protrusions. They roll heavily in even moderate seas.
(They are designed to 'climb up' on the ice and 'break' it with their weight as the move forward)
Their hulls were extremely thick.
Artic research ships could avoid some of these problems but there still is a lot of ice floating around that can put them at risk.

How's this for a large icebreaker? The 8" hull plating ought to protect against most ice.

Of course, she's unprotected against the Filipino Antarctic Battlecruiser...

RRS Thule, Rockall Icebreaker laid down 1930

Displacement:
7,729 t light; 7,985 t standard; 12,536 t normal; 16,176 t full load

Dimensions: Length overall / water x beam x draught
300.00 ft / 300.00 ft x 80.00 ft (Bulges 150.00 ft) x 15.00 ft (normal load)
91.44 m / 91.44 m x 24.38 m (Bulges 45.72 m) x 4.57 m

Armament:
1 - 2.50" / 63.5 mm guns in single mounts, 8.00lbs / 3.63kg shells, 1930 Model
Anti-aircraft gun in deck mount
on centreline aft
2 - 1.00" / 25.4 mm guns in single mounts, 0.50lbs / 0.23kg shells, 1930 Model
Machine guns in deck mounts
on side, all aft
2 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1930 Model
Machine guns in deck mounts
on side, all amidships
Weight of broadside 9 lbs / 4 kg
Shells per gun, main battery: 1,000

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Ends: 8.00" / 203 mm 100.00 ft / 30.48 m 25.00 ft / 7.62 m
200.00 ft / 60.96 m Unarmoured ends

- Torpedo Bulkhead and Bulges:
4.00" / 102 mm 300.00 ft / 91.44 m 15.00 ft / 4.57 m

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 11,728 shp / 8,749 Kw = 16.00 kts
Range 18,000nm at 16.00 kts
Bunker at max displacement = 8,191 tons

Complement:
592 - 770

Cost:
£1.343 million / $5.373 million

Distribution of weights at normal displacement:
Armament: 1 tons, 0.0 %
Armour: 1,406 tons, 11.2 %
- Belts: 740 tons, 5.9 %
- Torpedo bulkhead: 666 tons, 5.3 %
- Armament: 0 tons, 0.0 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 355 tons, 2.8 %
Hull, fittings & equipment: 5,366 tons, 42.8 %
Fuel, ammunition & stores: 4,807 tons, 38.3 %
Miscellaneous weights: 600 tons, 4.8 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
114,542 lbs / 51,956 Kg = 14,661.4 x 2.5 " / 64 mm shells or 83.6 torpedoes
Stability (Unstable if below 1.00): 2.17
Metacentric height 12.0 ft / 3.6 m
Roll period: 18.2 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 1.55

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.650
Length to Beam Ratio: 2.00 : 1
'Natural speed' for length: 17.32 kts
Power going to wave formation at top speed: 56 %
Trim (Max stability = 0, Max steadiness = 100): 33
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: 35.00 ft / 10.67 m
- Forecastle (20 %): 35.00 ft / 10.67 m
- Mid (40 %): 35.00 ft / 10.67 m (20.00 ft / 6.10 m aft of break)
- Quarterdeck (15 %): 20.00 ft / 6.10 m
- Stern: 20.00 ft / 6.10 m
- Average freeboard: 26.00 ft / 7.92 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 21.8 %
- Above water (accommodation/working, high = better): 145.6 %
Waterplane Area: 18,385 Square feet or 1,708 Square metres
Displacement factor (Displacement / loading): 460 %
Structure weight / hull surface area: 170 lbs/sq ft or 828 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.31
- Longitudinal: 5.77
- Overall: 1.52
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

Interesting, but

Quoted

200.00 ft / 60.96 m Unarmoured ends

has me concerned. I would think that the ends would have extra-thick plating (and my design, with an armour scheme based on one of Admiral K's does) .

Antarctic Battlecruiser? What Antarctic Battlecruiser?
*has Garcia stand in front of ABC to hide it*
I don't see no steenkin' Antarctic Battlecruiser!!
^_^

Why not build a real Antarctic Battlecruiser instead of that flimsy 4000 ton tin can.
I think that Garcia is big enough to block the entire ABC with room to spare.
:-)

Quoted

Originally posted by Swamphen
Interesting, but

Quoted

200.00 ft / 60.96 m Unarmoured ends

has me concerned. I would think that the ends would have extra-thick plating (and my design, with an armour scheme based on one of Admiral K's does) .

Yes, the 200 feet that's unarmoured is the 200 feet nearest the stern. It's a 300 foot ship, y'know...

RLBH

Ah, that makes more sense.

(But it does beg the question of what happens when you need to back up...)

Quoted

That design is entirely too normal. I insist you add more armor and more guns. And make it bigger while you're at it.

Whats the problem with being normal?

Bigger, Meaner, Icebreaker.

HMS Erebrus/Terror, Australia Icebreaker laid down 1931

Displacement:
4,629 t light; 4,801 t standard; 6,903 t normal; 8,585 t full load

Dimensions: Length overall / water x beam x draught
420.00 ft / 420.00 ft x 59.00 ft x 15.00 ft (normal load)
128.02 m / 128.02 m x 17.98 m x 4.57 m

Armament:
3 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1931 Model
Breech loading guns in deck mounts
on centreline ends, majority forward, 1 raised mount
4 - 2.95" / 75.0 mm guns (2x2 guns), 12.87lbs / 5.84kg shells, 1931 Model
Dual purpose guns in deck mounts
on centreline, all aft, all raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1931 Model
Anti-aircraft guns in deck mounts
on centreline, all amidships, all raised mounts - superfiring
4 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1931 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 384 lbs / 174 kg
Shells per gun, main battery: 150

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2.00" / 51 mm 270.00 ft / 82.30 m 10.00 ft / 3.05 m
Ends: 4.00" / 102 mm 150.00 ft / 45.72 m 10.00 ft / 3.05 m
Main Belt covers 99 % of normal length

- Torpedo Bulkhead:
2.00" / 51 mm 270.00 ft / 82.30 m 15.00 ft / 4.57 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2.00" / 51 mm - -
2nd: 0.50" / 13 mm - -

Machinery:
Diesel Internal combustion motors,
Geared drive, 4 shafts, 13,336 shp / 9,949 Kw = 20.00 kts
Range 20,000nm at 15.00 kts
Bunker at max displacement = 3,784 tons

Complement:
378 - 492

Cost:
£1.127 million / $4.507 million

Distribution of weights at normal displacement:
Armament: 48 tons, 0.7 %
Armour: 780 tons, 11.3 %
- Belts: 457 tons, 6.6 %
- Torpedo bulkhead: 300 tons, 4.3 %
- Armament: 24 tons, 0.3 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 399 tons, 5.8 %
Hull, fittings & equipment: 2,782 tons, 40.3 %
Fuel, ammunition & stores: 2,274 tons, 32.9 %
Miscellaneous weights: 620 tons, 9.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
27,378 lbs / 12,418 Kg = 253.5 x 6.0 " / 152 mm shells or 7.3 torpedoes
Stability (Unstable if below 1.00): 1.44
Metacentric height 4.3 ft / 1.3 m
Roll period: 12.0 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.05
Seaboat quality (Average = 1.00): 1.61

Hull form characteristics:
Hull has low quarterdeck
Block coefficient: 0.650
Length to Beam Ratio: 7.12 : 1
'Natural speed' for length: 20.49 kts
Power going to wave formation at top speed: 48 %
Trim (Max stability = 0, Max steadiness = 100): 44
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: 19.00 ft / 5.79 m
- Forecastle (20 %): 17.00 ft / 5.18 m
- Mid (50 %): 17.00 ft / 5.18 m
- Quarterdeck (15 %): 15.00 ft / 4.57 m (17.00 ft / 5.18 m before break)
- Stern: 15.00 ft / 4.57 m
- Average freeboard: 16.86 ft / 5.14 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 53.5 %
- Above water (accommodation/working, high = better): 162.6 %
Waterplane Area: 18,983 Square feet or 1,764 Square metres
Displacement factor (Displacement / loading): 267 %
Structure weight / hull surface area: 104 lbs/sq ft or 507 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.36
- Longitudinal: 1.80
- Overall: 1.40
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