WesWorld

A look ahead to what new classes will be laying down on the slipways next year.

To support the growth of the carrier fleet the requirement for an additional aircraft tender like HMS Unicorn was studied in 1948 but deferred. The DNC offered a modernised Unicorn design with revised armament and thinner box armour around the magazines. It was found easier and cheaper to design a modified Colossus Class ship with the 4.5in guns and one catapult removed and more extensive workshop equipment added. One ship, HMS Perseus has been approved and will be laid down during 1949.


HMS Perseus, Great Britain Aircraft Carrier Tender laid down 1949

Displacement:
16,014 t light; 16,525 t standard; 18,805 t normal; 20,628 t full load

Dimensions: Length overall / water x beam x draught
701.28 ft / 685.00 ft x 96.00 ft x 18.50 ft (normal load)
213.75 m / 208.79 m x 29.26 m x 5.64 m

Armament:
16 - 2.24" / 57.0 mm guns (4x4 guns), 6.00lbs / 2.72kg shells, 1950 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
12 - 1.57" / 40.0 mm guns (6x2 guns), 2.00lbs / 0.91kg shells, 1945 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 120 lbs / 54 kg
Shells per gun, main battery: 1,800

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3.00" / 76 mm 170.00 ft / 51.82 m 9.00 ft / 2.74 m
Ends: Unarmoured
Main Belt covers 38 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Torpedo Bulkhead:
1.00" / 25 mm 510.00 ft / 155.45 m 17.00 ft / 5.18 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm 1.00" / 25 mm -
2nd: 0.50" / 13 mm 0.50" / 13 mm -

- Armour deck: 2.00" / 51 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 115,000 shp / 85,790 Kw = 31.11 kts
Range 12,000nm at 16.00 kts
Bunker at max displacement = 4,102 tons

Complement:
802 - 1,043

Cost:
£7.344 million / $29.376 million

Distribution of weights at normal displacement:
Armament: 14 tons, 0.1 %
Armour: 2,283 tons, 12.1 %
- Belts: 259 tons, 1.4 %
- Torpedo bulkhead: 321 tons, 1.7 %
- Armament: 19 tons, 0.1 %
- Armour Deck: 1,684 tons, 9.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 2,780 tons, 14.8 %
Hull, fittings & equipment: 6,687 tons, 35.6 %
Fuel, ammunition & stores: 2,790 tons, 14.8 %
Miscellaneous weights: 4,250 tons, 22.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
34,200 lbs / 15,513 Kg = 6,052.5 x 2.2 " / 57 mm shells or 5.5 torpedoes
Stability (Unstable if below 1.00): 1.23
Metacentric height 6.8 ft / 2.1 m
Roll period: 15.4 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 1.12

Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0.541
Length to Beam Ratio: 7.14 : 1
'Natural speed' for length: 26.17 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 62
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 5.00 ft / 1.52 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 31.00 ft / 9.45 m
- Forecastle (25 %): 31.00 ft / 9.45 m (21.00 ft / 6.40 m aft of break)
- Mid (50 %): 21.00 ft / 6.40 m
- Quarterdeck (15 %): 21.00 ft / 6.40 m
- Stern: 21.00 ft / 6.40 m
- Average freeboard: 23.50 ft / 7.16 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 94.3 %
- Above water (accommodation/working, high = better): 227.0 %
Waterplane Area: 45,508 Square feet or 4,228 Square metres
Displacement factor (Displacement / loading): 154 %
Structure weight / hull surface area: 111 lbs/sq ft or 542 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.02
- Longitudinal: 1.14
- Overall: 1.03
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform

Class Names: HMS Perseus

Belt is box armour around magazines

Hangar deck: 545 x 65 x 17.5ft
Served by two 55 x 44ft lifts with capacity for 30,000lbs
One hydralic accelerators with capacity for 30,000lbs aircraft
Arrestor gear of 9 wires, 1 trickle wire, 2 forward wires and two safety barriers

Aircraft capacity: 9 (spread wings), 24 (folded wings), maximum hangar capacity 40
18 crated spare aircraft carried
Carries two self-propelled Lighters

Electric Equipment:
One Aerial Search Type 971 set
One Surface Search (High Definition) Type 274Q set
One Target Indication Type 287 set
Six MRS8 fire-control systems using CRBF directors with Type 262 RDF sets
Passive Radio Interception UA1 set
VHF Direction Finder Type 295Q

Looks reasonable from a technical point of view. From my perspective, the speed looks a bit excessive for a tender or maintenance vessel, but that would depend upon how you envision it being employed. Likewise the armor. But other than that, I see no issues.

Its a cheap conversion of an existing design so the armour and engines are unchanged.
Being a high-value asset some armour is only logical and speed is needed for launching etc. and keeping up with the main carrier fleet (albeit at a safe distance), so using an off-the-shelf design made sense. And if things get dire, the design is capable of use as a fighter carrier (at least as long as piston engine fighters remain in service).

A couple of heavy cruisers and a rebuilt trials ship.

Beyond the Wiltshire Class the Admiralty looked at another repeat Northumberland. The DNC offered a modernised design (CA6) with the new YARD powerplant, in this case three 30,000hp units giving a three-shaft layout. The belt armour was modified to that of the Wiltshire so the overall effect has been to reduce weight and cost with the benefits of improved speed and increased range (1,000nm at 20kts). The DNC then offered a further improved version (CA6a) with the 4.5in battery replaced by eight twin 3in L/50 and the new 57mm quad mount which offered even more weight saving and formidable anti-aircraft firepower. A modernised fire-control suite is also to be fitted. Four ships will be completed as the Cumberland Class.

Cumberland Class, Great Britain Heavy Cruiser laid down 1949

Displacement:
12,737 t light; 13,499 t standard; 15,830 t normal; 17,695 t full load

Dimensions: Length overall / water x beam x draught
661.91 ft / 655.00 ft x 76.00 ft x 21.00 ft (normal load)
201.75 m / 199.64 m x 23.16 m x 6.40 m

Armament:
9 - 7.50" / 191 mm guns (3x3 guns), 250.00lbs / 113.40kg shells, 1945 Model
Automatic rapid fire guns in turrets (on barbettes)
on centreline ends, majority forward, 1 raised mount - superfiring
16 - 3.00" / 76.2 mm guns (8x2 guns), 12.50lbs / 5.67kg shells, 1950 Model
Automatic rapid fire guns in deck mounts with hoists
on side ends, evenly spread
16 - 2.24" / 57.0 mm guns (4x4 guns), 6.00lbs / 2.72kg shells, 1950 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 2.00lbs / 0.91kg shells, 1945 Model
Anti-aircraft guns in deck mounts
on side, all aft, all raised mounts - superfiring
Weight of broadside 2,554 lbs / 1,158 kg
Shells per gun, main battery: 300
12 - 24.5" / 622.3 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 6.00" / 152 mm 350.00 ft / 106.68 m 13.00 ft / 3.96 m
Ends: Unarmoured
Main Belt covers 82 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 6.00" / 152 mm 3.00" / 76 mm 4.00" / 102 mm
2nd: 1.00" / 25 mm 1.00" / 25 mm 2.00" / 51 mm
3rd: 1.00" / 25 mm 1.00" / 25 mm -
4th: 0.50" / 13 mm 0.50" / 13 mm -

- Armour deck: 3.00" / 76 mm, Conning tower: 1.00" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Electric motors, 3 shafts, 90,000 shp / 67,140 Kw = 31.43 kts
Range 9,000nm at 20.00 kts
Bunker at max displacement = 4,197 tons

Complement:
705 - 917

Cost:
£7.844 million / $31.376 million

Distribution of weights at normal displacement:
Armament: 329 tons, 2.1 %
Armour: 3,648 tons, 23.0 %
- Belts: 1,196 tons, 7.6 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 469 tons, 3.0 %
- Armour Deck: 1,969 tons, 12.4 %
- Conning Tower: 14 tons, 0.1 %
Machinery: 2,176 tons, 13.7 %
Hull, fittings & equipment: 6,134 tons, 38.7 %
Fuel, ammunition & stores: 3,093 tons, 19.5 %
Miscellaneous weights: 450 tons, 2.8 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
31,663 lbs / 14,362 Kg = 150.1 x 7.5 " / 191 mm shells or 3.4 torpedoes
Stability (Unstable if below 1.00): 1.19
Metacentric height 4.6 ft / 1.4 m
Roll period: 14.9 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.34
Seaboat quality (Average = 1.00): 1.20

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.530
Length to Beam Ratio: 8.62 : 1
'Natural speed' for length: 29.45 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 58
Bow angle (Positive = bow angles forward): 12.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 32.50 ft / 9.91 m
- Forecastle (20 %): 26.00 ft / 7.92 m
- Mid (65 %): 23.00 ft / 7.01 m (16.00 ft / 4.88 m aft of break)
- Quarterdeck (20 %): 16.00 ft / 4.88 m
- Stern: 17.90 ft / 5.46 m
- Average freeboard: 22.54 ft / 6.87 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 66.2 %
- Above water (accommodation/working, high = better): 166.0 %
Waterplane Area: 35,483 Square feet or 3,296 Square metres
Displacement factor (Displacement / loading): 143 %
Structure weight / hull surface area: 120 lbs/sq ft or 584 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.96
- Longitudinal: 1.35
- 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
Good seaboat, rides out heavy weather easily

Class Names: Cumberland, Devonshire, Norfolk, Antrim

RDF Sets
One Aerial Search Type 971 set
One Surface Search Type 970 set
One Height-Finder and Surface Search Type 277 set
Two LRS1 fire-control systems using LRS Directors with twin Type 901 RDF sets
Three MRS7 fire-control systems using Mk.6M Gunnery Directors with twin Type 988 RDF sets and Simple Electric Deflection Calculator and Flyplane
Four MRS8 fire-control systems using Close-Range Blind Fire (CRBF) directors with Type 262 RDF sets
HF/DF Type 292
Passive Intercept Type UA1
Four RU-series jammers
ASDIC Type 146M



The four Howe Class cruisers will be refitted with updated electronics and fire-control systems and will lose their catapults and aircraft.


Howe Class, Great Britain Heavy Cruiser laid down 1927 (Engine 1942)

Displacement:
9,910 t light; 10,387 t standard; 11,865 t normal; 13,048 t full load

Dimensions: Length overall / water x beam x draught
615.64 ft / 610.00 ft x 68.25 ft x 19.00 ft (normal load)
187.65 m / 185.93 m x 20.80 m x 5.79 m

Armament:
8 - 8.00" / 203 mm guns (4x2 guns), 290.00lbs / 131.54kg shells, 1927 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread, 2 raised mounts - superfiring
8 - 4.50" / 114 mm guns (4x2 guns), 45.56lbs / 20.67kg shells, 1938 Model
Dual purpose guns in deck mounts with hoists
on side, all amidships
8 - 2.24" / 57.0 mm guns (4x2 guns), 5.65lbs / 2.56kg shells, 1946 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
12 - 1.57" / 40.0 mm guns (6x2 guns), 1.95lbs / 0.88kg shells, 1941 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread, all raised mounts - superfiring
Weight of broadside 2,753 lbs / 1,249 kg
Shells per gun, main battery: 150
6 - 24.5" / 622.3 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2.00" / 51 mm 300.00 ft / 91.44 m 12.00 ft / 3.66 m
Ends: 4.00" / 102 mm 100.00 ft / 30.48 m 12.00 ft / 3.66 m
210.00 ft / 64.01 m Unarmoured ends
Main Belt covers 76 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 3.00" / 76 mm 2.00" / 51 mm 1.00" / 25 mm
2nd: 1.00" / 25 mm 0.50" / 13 mm 1.00" / 25 mm
3rd: 0.50" / 13 mm 0.50" / 13 mm -
4th: 0.50" / 13 mm 0.50" / 13 mm -

- Armour deck: 2.00" / 51 mm, Conning tower: 1.00" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 88,058 shp / 65,692 Kw = 31.35 kts
Range 10,000nm at 16.00 kts
Bunker at max displacement = 2,662 tons

Complement:
567 - 738

Cost:
£3.380 million / $13.519 million

Distribution of weights at normal displacement:
Armament: 310 tons, 2.6 %
Armour: 1,783 tons, 15.0 %
- Belts: 496 tons, 4.2 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 226 tons, 1.9 %
- Armour Deck: 1,050 tons, 8.9 %
- Conning Tower: 11 tons, 0.1 %
Machinery: 2,300 tons, 19.4 %
Hull, fittings & equipment: 5,386 tons, 45.4 %
Fuel, ammunition & stores: 1,955 tons, 16.5 %
Miscellaneous weights: 130 tons, 1.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
20,258 lbs / 9,189 Kg = 79.1 x 8.0 " / 203 mm shells or 2.2 torpedoes
Stability (Unstable if below 1.00): 1.19
Metacentric height 3.9 ft / 1.2 m
Roll period: 14.6 seconds
Steadiness - As gun platform (Average = 50 %): 69 %
- Recoil effect (Restricted arc if above 1.00): 0.63
Seaboat quality (Average = 1.00): 1.40

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.525
Length to Beam Ratio: 8.94 : 1
'Natural speed' for length: 24.70 kts
Power going to wave formation at top speed: 56 %
Trim (Max stability = 0, Max steadiness = 100): 49
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: 32.00 ft / 9.75 m
- Forecastle (20 %): 26.00 ft / 7.92 m
- Mid (50 %): 24.00 ft / 7.32 m
- Quarterdeck (15 %): 24.00 ft / 7.32 m
- Stern: 24.00 ft / 7.32 m
- Average freeboard: 25.18 ft / 7.67 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 85.1 %
- Above water (accommodation/working, high = better): 201.7 %
Waterplane Area: 28,384 Square feet or 2,637 Square metres
Displacement factor (Displacement / loading): 132 %
Structure weight / hull surface area: 116 lbs/sq ft or 567 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.92
- Longitudinal: 2.00
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Good seaboat, rides out heavy weather easily

Refit Notes:

Replacement of 4in twins with 4,5in DP twin mounts
Replacement of 2pdr octuple mounts with 6pdr twin mounts
Addition of six twin 2pdr L/70 mounts
Removal of third aircraft
2 inch extra armour on main turret fronts and 1 inch on the roofs
1 inch extra armour on the main deck
New turbines and boilers
Two HACS Mk.IV
Radio-Location sets: one Type 284, one Type 285M, two Type 282M, one Type 283, one Type 276, one Type 271M, Passive Radio Intercept Type 293 (P,Q,M) and Passive RDF Intercept Type 294 and 294M

1948 Refit Notes
Removal of all aircraft and catapult
6pdr twin mounts updated with newer model
RDF and fire control systems updated

One Aerial Search Type 971 set
One Surface Search Type 970 set
One Height-Finder and Surface Search Type 277 set
Type 290 splash-spotting sets added to main director
Two Close-Range Blind Fire (CRBF) directors with Type 289 RDF
Passive Radio Intercept Type 293 series
Passive RDF intercept Type 297
Two RU-series jammers


The retired County Class cruiser HMS Suffolk will be rebuilt as a weapons trials ship with several new gun mounts. These will include a twin 5.5in mount based on the gun used in the Town Class cruiser-destroyers, a new 3in L/50 automatic gun for rapid-fire AA and anti-destroyer fire for vessels unable to carry the 4.5in gun or for major vessels which need additional AA firepower. The DNO also outlined a quadruple 6pdr AA using the same basic mount as the new sextuple 2pdr.

HMS Suffolk, Great Britain Weapons Trials Ship laid down 1924

Displacement:
9,761 t light; 10,052 t standard; 11,539 t normal; 12,729 t full load

Dimensions: Length overall / water x beam x draught
581.19 ft / 570.00 ft x 60.00 ft x 22.71 ft (normal load)
177.15 m / 173.74 m x 18.29 m x 6.92 m

Armament:
2 - 5.50" / 140 mm guns (1x2 guns), 80.00lbs / 36.29kg shells, 1945 Model
Automatic rapid fire guns in a deck mount with hoist
on centreline forward
2 - 4.50" / 114 mm guns (1x2 guns), 45.00lbs / 20.41kg shells, 1949 Model
Automatic rapid fire guns in a deck mount with hoist
on centreline aft
2 - 3.00" / 76.2 mm guns (1x2 guns), 12.50lbs / 5.67kg shells, 1950 Model
Automatic rapid fire guns in a deck mount with hoist
on centreline aft, all raised guns - superfiring
6 - 1.57" / 40.0 mm guns (1x6 guns), 2.00lbs / 0.91kg shells, 1947 Model
Anti-aircraft guns in deck mount
on centreline forward, all raised guns - superfiring
4 - 2.24" / 57.0 mm guns (1x4 guns), 6.00lbs / 2.72kg shells, 1950 Model
Anti-aircraft guns in deck mount
on side amidships, all raised guns
Weight of broadside 311 lbs / 141 kg
Shells per gun, main battery: 300

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 4.50" / 114 mm 405.00 ft / 123.44 m 9.30 ft / 2.83 m
Ends: Unarmoured
Main Belt covers 109 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.50" / 38 mm 1.00" / 25 mm 3.00" / 76 mm
2nd: 1.00" / 25 mm 1.00" / 25 mm 3.00" / 76 mm
3rd: 1.00" / 25 mm 1.00" / 25 mm 3.00" / 76 mm
4th: 1.00" / 25 mm 1.00" / 25 mm -
5th: 1.00" / 25 mm 1.00" / 25 mm -

- Armour deck: 2.00" / 51 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 95,294 shp / 71,089 Kw = 32.00 kts
Range 10,100nm at 15.00 kts
Bunker at max displacement = 2,678 tons

Complement:
556 - 723

Cost:
£2.536 million / $10.145 million

Distribution of weights at normal displacement:
Armament: 47 tons, 0.4 %
Armour: 1,586 tons, 13.7 %
- Belts: 699 tons, 6.1 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 28 tons, 0.2 %
- Armour Deck: 859 tons, 7.4 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 3,139 tons, 27.2 %
Hull, fittings & equipment: 4,490 tons, 38.9 %
Fuel, ammunition & stores: 1,778 tons, 15.4 %
Miscellaneous weights: 500 tons, 4.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
14,254 lbs / 6,465 Kg = 171.3 x 5.5 " / 140 mm shells or 1.6 torpedoes
Stability (Unstable if below 1.00): 1.23
Metacentric height 3.4 ft / 1.0 m
Roll period: 13.7 seconds
Steadiness - As gun platform (Average = 50 %): 61 %
- Recoil effect (Restricted arc if above 1.00): 0.07
Seaboat quality (Average = 1.00): 1.10

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.520
Length to Beam Ratio: 9.50 : 1
'Natural speed' for length: 23.87 kts
Power going to wave formation at top speed: 59 %
Trim (Max stability = 0, Max steadiness = 100): 55
Bow angle (Positive = bow angles forward): 25.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 24.00 ft / 7.32 m
- Forecastle (20 %): 23.00 ft / 7.01 m
- Mid (50 %): 20.00 ft / 6.10 m
- Quarterdeck (15 %): 18.00 ft / 5.49 m
- Stern: 18.00 ft / 5.49 m
- Average freeboard: 20.48 ft / 6.24 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 96.9 %
- Above water (accommodation/working, high = better): 160.2 %
Waterplane Area: 23,209 Square feet or 2,156 Square metres
Displacement factor (Displacement / loading): 132 %
Structure weight / hull surface area: 116 lbs/sq ft or 565 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.21
- Longitudinal: 1.92
- Overall: 1.27
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent

Weapons Trials Rebuild
Removal of all previous armament and electronics
Refurbishment of internal fittings
Reconstructed bridge and forward superstructure

Weapons Fit
'A' Position: twin 5.5in automatic mount (cancelled 6in auto turret with Canadian Vickers 5.5in)
'B' Position: sextuple 40mm mount (improved model)
'X' Position: twin 3in L/70 (experimental new gun and mount)
'Y' Position: twin 4.5in (new lighter mount)
'S1' Position: quadruple 57mm (6pdr) (experimental mount)


Electronics Fit
Two Surface Search Type 970
One Target Indication Type 975
One Height-Finding and Surface Search Type 977
One Prototype LRS.1 director with two Type 901
One Prototype MRS.3 director with Type 903
One Mk. VI director with two Type 288 with Tallboy console and Flyplane table
Two CRBF directors with Type 289
VHF Direction Finder Type 295Q

And something new for the slipways next year as well.

The availability of funds has seen the Fleet Aircraft Direction Escort inserted into the building programme. This class of escort is to direct carrier-based fighters onto incoming aerial threats to surface groups and convoys. A full set of interception RDF equipment (Types 971, 972 and 287Q) is fitted along with dedicated AIO spaces.

It had been planned to convert the Cathedral Class scouts. The DNC drew up two sketch designs with two 4.5in Mk.VI mounts; FADE A featured 4.5in mounts in A and Q position with one sextuple 40mm mount in B position and FADE B had both 4.5in Mk.VI mounts forward. All torpedo tubes were removed and additional generator capacity would be provided and the superstructures remodelled. It was found that there was insufficient space and weight margin for the full FADE equipment. The DNC then considered a FADE based on the Town Class hull with the 5.5in guns replaced by two 4.5in Mk.VI mounts in A and Q positions. The result was satisfactory but it was felt the hull was larger than desired and the result more expensive. The DNC then took a Battle Class destroyer hull, removing B mount and retaining the same 45,000hp machinery but with additional generator capacity. The result was very satisfactory and following Board Approval the order went out to the shipyards for six hulls under the 1949 Programme as the Leopard Class.


Leopard Class, Great Britain Fleet Aircraft Direction Escort (FADE) laid down 1948

Displacement:
2,005 t light; 2,099 t standard; 2,390 t normal; 2,622 t full load

Dimensions: Length overall / water x beam x draught
378.59 ft / 366.00 ft x 40.00 ft x 13.70 ft (normal load)
115.39 m / 111.56 m x 12.19 m x 4.18 m

Armament:
4 - 4.50" / 114 mm guns (2x2 guns), 45.00lbs / 20.41kg shells, 1945 Model
Automatic rapid fire guns in deck mounts with hoists
on centreline ends, evenly spread
8 - 1.57" / 40.0 mm guns (4x2 guns), 2.00lbs / 0.91kg shells, 1945 Model
Anti-aircraft guns in deck mounts
on side, all amidships, all raised mounts - superfiring
Weight of broadside 196 lbs / 89 kg
Shells per gun, main battery: 400

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.50" / 38 mm 1.00" / 25 mm 1.00" / 25 mm
2nd: 0.50" / 13 mm 0.50" / 13 mm -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 45,000 shp / 33,570 Kw = 34.02 kts
Range 5,800nm at 16.00 kts
Bunker at max displacement = 524 tons

Complement:
170 - 222

Cost:
£1.794 million / $7.174 million

Distribution of weights at normal displacement:
Armament: 29 tons, 1.2 %
Armour: 18 tons, 0.8 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 18 tons, 0.8 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 1,042 tons, 43.6 %
Hull, fittings & equipment: 716 tons, 30.0 %
Fuel, ammunition & stores: 385 tons, 16.1 %
Miscellaneous weights: 200 tons, 8.4 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
916 lbs / 415 Kg = 20.1 x 4.5 " / 114 mm shells or 0.4 torpedoes
Stability (Unstable if below 1.00): 1.30
Metacentric height 2.0 ft / 0.6 m
Roll period: 11.8 seconds
Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.18
Seaboat quality (Average = 1.00): 1.11

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.417
Length to Beam Ratio: 9.15 : 1
'Natural speed' for length: 22.24 kts
Power going to wave formation at top speed: 69 %
Trim (Max stability = 0, Max steadiness = 100): 45
Bow angle (Positive = bow angles forward): 25.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 27.00 ft / 8.23 m
- Forecastle (20 %): 20.00 ft / 6.10 m
- Mid (45 %): 16.50 ft / 5.03 m
- Quarterdeck (15 %): 16.50 ft / 5.03 m
- Stern: 16.50 ft / 5.03 m
- Average freeboard: 18.20 ft / 5.55 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 160.5 %
- Above water (accommodation/working, high = better): 181.9 %
Waterplane Area: 9,455 Square feet or 878 Square metres
Displacement factor (Displacement / loading): 90 %
Structure weight / hull surface area: 38 lbs/sq ft or 185 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 2.67
- Overall: 0.59
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent

Class Names: HMS Leopard, Lynx, Puma, Cheetah, Tiger, Cougar

Misc weight includes:
ASDIC Type 148
Depth-Finding ASDIC Type 145
Passive ASDIC Type 147
One Aerial Search Type 971 set
Two Height-Finder Type 972 sets
One Target Indication Type 287Q set
One Surface Search Type 970 set
Gunnery Director Set Type 288 with Tallboy console and Flyplane
One Close-Range Blind Fire director with Type 289 RDF
VHF Direction Finder Type 295Q
Passive Radio Intercept Type 293 series
Passive Radar Intercept Type 297
Two RU-series jammers
2 Squid A/S mortar and ammunition

Also laying down during 1949 are some new auxiliaries.
Two new repair ships based on the Hecla tender design will replace the existing aging HMS Reliance and HMS Scotstoun.
To support the Bar Class boom defence vessels it was decided to order a second Guardian Class netlayer. The 1936 design being updated with a new diesel powerplant and a more effective AA armament fitted. Just one ship, HMS Sentry, is planned.


HMS Reliance, HMS Scotstoun, Great Britain Repair Ship laid down 1949

Displacement:
11,124 t light; 11,424 t standard; 12,560 t normal; 13,469 t full load

Dimensions: Length overall / water x beam x draught
574.58 ft / 570.00 ft x 85.50 ft x 20.00 ft (normal load)
175.13 m / 173.74 m x 26.06 m x 6.10 m

Armament:
4 - 4.50" / 114 mm guns (2x2 guns), 45.00lbs / 20.41kg shells, 1936 Model
Dual purpose guns in deck mounts with hoists
on centreline ends, evenly spread
12 - 1.57" / 40.0 mm guns (6x2 guns), 2.00lbs / 0.91kg shells, 1945 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 204 lbs / 93 kg
Shells per gun, main battery: 400

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.50" / 38 mm 1.00" / 25 mm 1.00" / 25 mm
2nd: 0.50" / 13 mm 0.50" / 13 mm -

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 20,000 shp / 14,920 Kw = 21.01 kts
Range 15,000nm at 12.00 kts
Bunker at max displacement = 2,045 tons

Complement:
593 - 771

Cost:
£3.655 million / $14.620 million

Distribution of weights at normal displacement:
Armament: 26 tons, 0.2 %
Armour: 20 tons, 0.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 20 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 484 tons, 3.9 %
Hull, fittings & equipment: 4,355 tons, 34.7 %
Fuel, ammunition & stores: 1,436 tons, 11.4 %
Miscellaneous weights: 6,240 tons, 49.7 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
25,367 lbs / 11,506 Kg = 556.7 x 4.5 " / 114 mm shells or 3.4 torpedoes
Stability (Unstable if below 1.00): 1.13
Metacentric height 5.0 ft / 1.5 m
Roll period: 16.0 seconds
Steadiness - As gun platform (Average = 50 %): 61 %
- Recoil effect (Restricted arc if above 1.00): 0.02
Seaboat quality (Average = 1.00): 1.98

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.451
Length to Beam Ratio: 6.67 : 1
'Natural speed' for length: 23.87 kts
Power going to wave formation at top speed: 38 %
Trim (Max stability = 0, Max steadiness = 100): 31
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: 26.00 ft / 7.92 m
- Forecastle (20 %): 23.00 ft / 7.01 m
- Mid (50 %): 23.00 ft / 7.01 m
- Quarterdeck (15 %): 23.00 ft / 7.01 m
- Stern: 23.00 ft / 7.01 m
- Average freeboard: 23.24 ft / 7.08 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 69.1 %
- Above water (accommodation/working, high = better): 229.8 %
Waterplane Area: 31,112 Square feet or 2,890 Square metres
Displacement factor (Displacement / loading): 169 %
Structure weight / hull surface area: 99 lbs/sq ft or 481 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.69
- 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

Facilities include: stores, two furnaces capable of melting 500lbs at tempratures up to 1,500 degrees, a foundry, heavy and light machine shops with milling and grinding machines, electronics repair workshop, plumbers shop, carpenters shop, heavy and light machine shops and electrical and torpedo repair shops and plant for charging submarine batteries.

Type 970 X-band surface-search set
Four CRBF directors




Sentry, Great Britain Netlayer and Target Towing Ship laid down 1949

Displacement:
2,264 t light; 2,323 t standard; 2,422 t normal; 2,501 t full load

Dimensions: Length overall / water x beam x draught
315.36 ft / 310.00 ft x 53.00 ft x 12.00 ft (normal load)
96.12 m / 94.49 m x 16.15 m x 3.66 m

Armament:
6 - 1.57" / 40.0 mm guns (1x6 guns), 2.00lbs / 0.91kg shells, 1949 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
4 - 0.66" / 16.8 mm guns (2x2 guns), 0.14lbs / 0.06kg shells, 1949 Model
Machine guns in deck mounts
on side, all forward, all raised mounts - superfiring
Weight of broadside 13 lbs / 6 kg
Shells per gun, main battery: 1,500

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm 0.50" / 13 mm -
2nd: 0.50" / 13 mm - -

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 5,000 shp / 3,730 Kw = 18.21 kts
Range 5,000nm at 10.00 kts
Bunker at max displacement = 178 tons

Complement:
172 - 224

Cost:
£0.744 million / $2.977 million

Distribution of weights at normal displacement:
Armament: 2 tons, 0.1 %
Armour: 2 tons, 0.1 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 2 tons, 0.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 121 tons, 5.0 %
Hull, fittings & equipment: 919 tons, 38.0 %
Fuel, ammunition & stores: 159 tons, 6.5 %
Miscellaneous weights: 1,220 tons, 50.4 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
5,426 lbs / 2,461 Kg = 2,778.7 x 1.6 " / 40 mm shells or 1.5 torpedoes
Stability (Unstable if below 1.00): 1.08
Metacentric height 2.2 ft / 0.7 m
Roll period: 14.9 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.430
Length to Beam Ratio: 5.85 : 1
'Natural speed' for length: 17.61 kts
Power going to wave formation at top speed: 46 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 15.00 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 %): 20.00 ft / 6.10 m
- Mid (65 %): 20.00 ft / 6.10 m (10.00 ft / 3.05 m aft of break)
- Quarterdeck (20 %): 10.00 ft / 3.05 m
- Stern: 10.00 ft / 3.05 m
- Average freeboard: 16.50 ft / 5.03 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 72.6 %
- Above water (accommodation/working, high = better): 199.9 %
Waterplane Area: 10,317 Square feet or 959 Square metres
Displacement factor (Displacement / loading): 164 %
Structure weight / hull surface area: 61 lbs/sq ft or 296 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.90
- Longitudinal: 2.72
- 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

Sentry is equipped for Anti-Submarine Net laying, target towing and general photographic work with extensive darkroom facilties. In wartime mine laying rails can be fitted for 200 mines or 60x DCs.

Electronic Equipment:
1x Type 970 surface search
1x CRBF director