Posts: 1587 Joined: November 22nd, 2011, 4:47 am
Location: Marietta, Georgia - USA
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And this time a cruiser-minelayer, the Edmund Boyle Class. Laid down in 1924, two of these were commissioned in 1927, the HMS Edmund Boyle and the HMS Albert Stephens. They were designed to be capable both of independent operations and to operate with the fleet.
Edmund Boyle, Grays Harbor cruiser-minelayer laid down 1924 (Engine 1925)
Displacement:
10,065 t light; 10,327 t standard; 11,793 t normal; 12,966 t full load
Dimensions: Length overall / water x beam x draught
502.04 ft / 487.00 ft x 67.00 ft x 23.00 ft (normal load)
153.02 m / 148.44 m x 20.42 m x 7.01 m
Armament:
4 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1924 Model
Breech loading guns in turrets (on barbettes)
on centreline ends, evenly spread, 2 raised mounts - superfiring
6 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1924 Model
Breech loading guns in deck mounts
on side, all amidships
8 - 1.57" / 40.0 mm guns in single mounts, 1.95lbs / 0.88kg shells, 1924 Model
Breech loading guns in deck mounts
on side, all amidships, all raised mounts - superfiring
Weight of broadside 576 lbs / 261 kg
Shells per gun, main battery: 75
Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 5.00" / 127 mm 287.33 ft / 87.58 m 9.82 ft / 2.99 m
Ends: 4.00" / 102 mm 199.65 ft / 60.85 m 9.82 ft / 2.99 m
Upper: 4.00" / 102 mm 287.33 ft / 87.58 m 8.00 ft / 2.44 m
Main Belt covers 91 % of normal length
Main belt does not fully cover magazines and engineering spaces
- Torpedo Bulkhead:
4.00" / 102 mm 287.33 ft / 87.58 m 21.11 ft / 6.43 m
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2.00" / 51 mm - 3.00" / 76 mm
- Armour deck: 2.00" / 51 mm, Conning tower: 2.00" / 51 mm
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 53,303 shp / 39,764 Kw = 28.00 kts
Range 12,500nm at 14.00 kts
Bunker at max displacement = 2,639 tons
Complement:
565 - 735
Cost:
£2.025 million / $8.098 million
Distribution of weights at normal displacement:
Armament: 72 tons, 0.6 %
Armour: 3,249 tons, 27.5 %
- Belts: 1,313 tons, 11.1 %
- Torpedo bulkhead: 898 tons, 7.6 %
- Armament: 138 tons, 1.2 %
- Armour Deck: 877 tons, 7.4 %
- Conning Tower: 22 tons, 0.2 %
Machinery: 1,731 tons, 14.7 %
Hull, fittings & equipment: 2,214 tons, 18.8 %
Fuel, ammunition & stores: 1,728 tons, 14.7 %
Miscellaneous weights: 2,800 tons, 23.7 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
10,886 lbs / 4,938 Kg = 100.8 x 6.0 " / 152 mm shells or 2.6 torpedoes
Stability (Unstable if below 1.00): 1.04
Metacentric height 3.0 ft / 0.9 m
Roll period: 16.3 seconds
Steadiness - As gun platform (Average = 50 %): 74 %
- Recoil effect (Restricted arc if above 1.00): 0.16
Seaboat quality (Average = 1.00): 1.48
Hull form characteristics:
Hull has raised forecastle, rise forward of midbreak, raised quarterdeck
and transom stern
Block coefficient: 0.550
Length to Beam Ratio: 7.27 : 1
'Natural speed' for length: 25.70 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 16.20 degrees
Stern overhang: 4.00 ft / 1.22 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 38.00 ft / 11.58 m
- Forecastle (18 %): 30.50 ft / 9.30 m (29.50 ft / 8.99 m aft of break)
- Mid (37 %): 29.50 ft / 8.99 m (21.50 ft / 6.55 m aft of break)
- Quarterdeck (23 %): 22.00 ft / 6.71 m (21.50 ft / 6.55 m before break)
- Stern: 22.50 ft / 6.86 m
- Average freeboard: 25.35 ft / 7.73 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 112.1 %
- Above water (accommodation/working, high = better): 192.4 %
Waterplane Area: 23,707 Square feet or 2,202 Square metres
Displacement factor (Displacement / loading): 117 %
Structure weight / hull surface area: 56 lbs/sq ft or 273 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.53
- Longitudinal: 1.61
- Overall: 0.60
Caution: Hull subject to strain in open-sea
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
The armor belt was just kind-of a guesstimate as I did the SS prior to actually adding the belt. I figured since it is a cruiser-minelayer, and supposed to operate in forward combat zones, some armor along the lines of what a standard cruiser may have would not be out of line. I am also guessing that mine capacity would be somewhere around 600-800. I added 1600 misc. tons for that, and 800 tons for the catapult and aircraft facilities. There is only one catapult, and no hanger, the floatplane being covered with a tarpaulin when not in use. The 6"/45 main guns are in single turrets of the "weatherproof" type, so armor is minimal on them. The Boyles were the last ships built using that type turret. (I was thinking of having them replaced with twin 4.7"/45 twin mounts in the late 30's)
_________________ "Anybody remotely interesting is mad in some way." - The Seventh Doctor
Last edited by Zephyr on June 6th, 2012, 5:05 am, edited 3 times in total.
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