Alerter , laid down 1922, refitted 1932
Guard , laid down 1922, refitted 1932
Look-Out , laid down 1922, refitted 1932
Minder , laid down 1922, refitted 1932
Keeper , laid down 1922, refitted 1932, sunk 06-08-35 (bomb)
Watcher , laid down 1923, refitted 1932
Original Data
Displacement:
1.915 t light; 2.001 t standard; 2.277 t normal; 2.499 t full load
Dimensions: Length overall / water x beam x draught
303,84 ft / 295,28 ft x 37,40 ft x 13,12 ft (normal load)
92,61 m / 90,00 m x 11,40 m x 4,00 m
Armament:
4 - 5,00" / 127 mm guns in single mounts, 62,50lbs / 28,35kg shells, 1922 Model
Breech loading guns in deck mounts
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 3,46" / 88,0 mm guns (2x2 guns), 20,79lbs / 9,43kg shells, 1922 Model
Anti-aircraft guns in deck mounts
on side, all amidships
8 - 0,79" / 20,0 mm guns (4x2 guns), 0,24lbs / 0,11kg shells, 1922 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 335 lbs / 152 kg
Shells per gun, main battery: 200
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2,76" / 70 mm 190,29 ft / 58,00 m 7,22 ft / 2,20 m
Ends: 0,59" / 15 mm 65,62 ft / 20,00 m 7,22 ft / 2,20 m
39,37 ft / 12,00 m Unarmoured ends
Upper: 1,18" / 30 mm 190,29 ft / 58,00 m 6,56 ft / 2,00 m
Main Belt covers 99% of normal length
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1,57" / 40 mm 0,98" / 25 mm -
2nd: 0,98" / 25 mm 0,59" / 15 mm -
3rd: 0,39" / 10 mm - -
- Armour deck: 1,18" / 30 mm, Conning tower: 3,15" / 80 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 16.086 shp / 12.000 Kw = 24,38 kts
Range 8.000nm at 12,00 kts
Bunker at max displacement = 498 tons
Complement:
164 - 214
Cost:
£0,487 million / $1,948 million
Distribution of weights at normal displacement:
Armament: 42 tons, 1,8%
Armour: 441 tons, 19,3%
- Belts: 235 tons, 10,3%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 25 tons, 1,1%
- Armour Deck: 168 tons, 7,4%
- Conning Tower: 12 tons, 0,5%
Machinery: 546 tons, 24,0%
Hull, fittings & equipment: 787 tons, 34,6%
Fuel, ammunition & stores: 362 tons, 15,9%
Miscellaneous weights: 100 tons, 4,4%
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
3.179 lbs / 1.442 Kg = 50,9 x 5,0 " / 127 mm shells or 0,8 torpedoes
Stability (Unstable if below 1.00): 1,16
Metacentric height 1,5 ft / 0,5 m
Roll period: 12,8 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0,27
Seaboat quality (Average = 1.00): 1,25
Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0,550
Length to Beam Ratio: 7,89 : 1
'Natural speed' for length: 17,18 kts
Power going to wave formation at top speed: 64 %
Trim (Max stability = 0, Max steadiness = 100): 56
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 1,64 ft / 0,50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19,03 ft / 5,80 m
- Forecastle (20%): 17,06 ft / 5,20 m
- Mid (75%): 17,06 ft / 5,20 m (9,19 ft / 2,80 m aft of break)
- Quarterdeck (15%): 9,19 ft / 2,80 m
- Stern: 9,19 ft / 2,80 m
- Average freeboard: 15,25 ft / 4,65 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 97,7%
- Above water (accommodation/working, high = better): 141,9%
Waterplane Area: 7.707 Square feet or 716 Square metres
Displacement factor (Displacement / loading): 116%
Structure weight / hull surface area: 56 lbs/sq ft or 274 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,88
- Longitudinal: 3,33
- Overall: 1,01
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
Good seaboat, rides out heavy weather easily
After modernization
Displacement:
1.912 t light; 2.001 t standard; 2.277 t normal; 2.499 t full load
Dimensions: Length overall / water x beam x draught
303,84 ft / 295,28 ft x 37,40 ft x 13,12 ft (normal load)
92,61 m / 90,00 m x 11,40 m x 4,00 m
Armament:
4 - 5,00" / 127 mm guns in single mounts, 62,50lbs / 28,35kg shells, 1922 Model
Breech loading guns in deck mounts
on centreline ends, evenly spread, 2 raised mounts - superfiring
4 - 3,46" / 88,0 mm guns (2x2 guns), 20,79lbs / 9,43kg shells, 1922 Model
Anti-aircraft guns in deck mounts
on side, all amidships
8 - 1,57" / 40,0 mm guns (4x2 guns), 1,95lbs / 0,88kg shells, 1932 Model
Anti-aircraft guns in deck mounts
on side, all aft
10 - 0,79" / 20,0 mm guns (3 mounts), 0,24lbs / 0,11kg shells, 1922 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, 2 raised mounts
Weight of broadside 351 lbs / 159 kg
Shells per gun, main battery: 200
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 2,76" / 70 mm 190,29 ft / 58,00 m 7,22 ft / 2,20 m
Ends: 0,59" / 15 mm 65,62 ft / 20,00 m 7,22 ft / 2,20 m
39,37 ft / 12,00 m Unarmoured ends
Upper: 1,18" / 30 mm 190,29 ft / 58,00 m 6,56 ft / 2,00 m
Main Belt covers 99% of normal length
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1,57" / 40 mm 0,98" / 25 mm -
2nd: 0,98" / 25 mm 0,59" / 15 mm -
3rd: 0,59" / 15 mm - -
4th: 0,39" / 10 mm - -
- Armour deck: 1,18" / 30 mm, Conning tower: 3,15" / 80 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 16.086 shp / 12.000 Kw = 24,38 kts
Range 8.000nm at 12,00 kts
Bunker at max displacement = 498 tons
Complement:
164 - 214
Cost:
£0,491 million / $1,966 million
Distribution of weights at normal displacement:
Armament: 44 tons, 1,9%
Armour: 442 tons, 19,4%
- Belts: 235 tons, 10,3%
- Torpedo bulkhead: 0 tons, 0,0%
- Armament: 27 tons, 1,2%
- Armour Deck: 168 tons, 7,4%
- Conning Tower: 12 tons, 0,5%
Machinery: 546 tons, 24,0%
Hull, fittings & equipment: 781 tons, 34,3%
Fuel, ammunition & stores: 365 tons, 16,0%
Miscellaneous weights: 100 tons, 4,4%
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
3.145 lbs / 1.427 Kg = 50,3 x 5,0 " / 127 mm shells or 0,8 torpedoes
Stability (Unstable if below 1.00): 1,16
Metacentric height 1,5 ft / 0,5 m
Roll period: 12,8 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0,28
Seaboat quality (Average = 1.00): 1,26
Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0,550
Length to Beam Ratio: 7,89 : 1
'Natural speed' for length: 17,18 kts
Power going to wave formation at top speed: 64 %
Trim (Max stability = 0, Max steadiness = 100): 56
Bow angle (Positive = bow angles forward): 20,00 degrees
Stern overhang: 1,64 ft / 0,50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19,03 ft / 5,80 m
- Forecastle (20%): 17,06 ft / 5,20 m
- Mid (75%): 17,06 ft / 5,20 m (9,19 ft / 2,80 m aft of break)
- Quarterdeck (15%): 9,19 ft / 2,80 m
- Stern: 9,19 ft / 2,80 m
- Average freeboard: 15,25 ft / 4,65 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 98,4%
- Above water (accommodation/working, high = better): 141,9%
Waterplane Area: 7.707 Square feet or 716 Square metres
Displacement factor (Displacement / loading): 115%
Structure weight / hull surface area: 56 lbs/sq ft or 272 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0,87
- Longitudinal: 3,31
- Overall: 1,00
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
Good seaboat, rides out heavy weather easily