If you're building a flagship for a distant colonial location - something modest like Coquimbo, with a class one port and drydock handy - what features would you emphasize in the design?
Would it be a protected/light cruiser, a small armored cruiser, a monitor, or what?
Would you provide for an ability to do additional tasks such as minelaying?
I've just thrown together a notional design - basically a shortened Galapagos class ship, so she fits a class one dock. Traditional protected cruiser roles - trade defence, scouting, strikes - would be the emphasis. Weight is assigned for ~60 mines, flag facilities, and wireless, plus a growth margin. Layout of the main battery is similar to Gapapagos, but with fewer torps and a 65mm anti-airship gun replacing one of the midships 14 cm guns.
The speed takes a bit of a hit, not quite 26 knots, but with a high freeboard, she ought to be able to maintain that speed in heavy weather. Range, at 8000 nm, is high for a GC cruiser. I've retained all-coal firing for now...
I'm rejecting a small AC, as the lower speed would make it more difficult to respond to raiders, work with torpedo-craft, or evade big nasties if, for example, Peru were to attack in force.
Here's the springstyle - will play in springsharp tonight.
pc09a, laid down 1909
Length, 120.0 m x Beam, 13.5 m x Depth, 5.7 m
4004 tonnes normal displacement (3403 tonnes standard)
Main battery: 4 x 14.0-cm
Secondary battery: 1 x 6.5-cm
QF battery: 4 x 4.7-cm
Light battery: 4 x 0.8-cm
Weight of broadside: 162 kg
4 TT, 45.7 cm
Main belt, 7.5 cm; bow and stern, 2.5 cm
Armor deck, average 2.5 cm
Conning tower, 7.5 cm
Battery armor:
Main, 2.5 cm shields / secondary, 2.5 cm shields
QF, 2.5 cm shields / light guns, 1.0 cm shields
Maximum speed for 18004 shaft kw = 25.98 knots
Approximate cruising radius, 8000 nm / 10 knots
Typical complement: 252-327
Estimated cost, $1.286 million (£322,000)
Remarks:
Relative extent of belt armor, 112 percent of 'typical' coverage.
Ship has slow, easy roll; a good, steady gun platform.
Excellent seaboat; comfortable and able to fight her guns
in the heaviest weather.
Distribution of weights:
Percent
normal
displacement:
Armament ......................... 45 tonnes = 1 pct
Armor, total ..................... 532 tonnes = 13 pct
Belt 325 tonnes = 8 pct
Deck 180 tonnes = 4 pct
C.T. 16 tonnes = 0 pct
Armament 11 tonnes = 0 pct
Machinery ........................ 1206 tonnes = 30 pct
Hull and fittings; equipment ..... 1351 tonnes = 34 pct
Fuel, ammunition, stores ......... 711 tonnes = 18 pct
Miscellaneous weights ............ 160 tonnes = 4 pct
-----
4004 tonnes = 100 pct
Estimated metacentric height, 0.7 m
Displacement summary:
Light ship: 3293 tonnes
Standard displacement: 3403 tonnes
Normal service: 4004 tonnes
Full load: 4469 tonnes
Loading submergence 928 tonnes/metre
+++++++++++++++++++++++++
Estimated overall survivability and seakeeping ability:
Relative margin of stability: 1.24
Shellfire needed to sink: 1796 kg = 47.2 x 14.0-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)
Torpedoes needed to sink: 0.9
(Approximates number of 'typical'
torpedo hits needed to sink ship)
Relative steadiness as gun platform, 80 percent
(50 percent is 'average')
Relative rocking effect from firing to beam, 0.14
Relative quality as a seaboat: 1.59
+++++++++++++++++++++++++
Hull form characteristics:
Block coefficient: 0.43
Sharpness coefficient: 0.32
Hull speed coefficient 'M' = 7.58
'Natural speed' for length = 19.8 knots
Power going to wave formation
at top speed: 55 percent
Estimated hull characteristics and strength:
Relative underwater volume absorbed by
magazines and engineering spaces: 111 percent
Relative accommodation and working space: 111 percent
Displacement factor: 116 percent
(Displacement relative to loading factors)
Relative cross-sectional hull strength: 0.92
(Structure weight per square
metre of hull surface: 344 kg)
Relative longitudinal hull strength: 2.20
(for 5.10 m average freeboard;
freeboard adjustment +1.26 m)
Relative composite hull strength: 1.00
+++++++++++++++++++++++++
[Machine-readable parameters: Spring Style v. 1.2.1]
393.60 x 44.28 x 18.70; 16.73 -- Dimensions
0.43 -- Block coefficient
1909 -- Year laid down
25.98 / 8000 / 10.00; Turbine, coal fired -- Speed / radius / cruise
160 tons -- Miscellaneous weights
++++++++++
4 x 5.51; 0 -- Main battery; turrets
Central positioning of guns
Gun-shields
:
1 x 2.56; 0 -- Secondary battery; turrets
Gun-shields
:
4 x 1.85 -- Tertiary (QF/AA) battery
Gun-shields
:
4 x 0.31 -- Fourth (light) battery
4 / 0 / 17.99 -- TT / submerged / size
++++++++++
2.95 / 0.98 / 0.00 / 0.00; 112 -- Belt armor; relative extent
0.98 / 2.95 -- Deck / CT
0.98 / 0.98 / 0.98 / 0.39 -- Battery armor
(Note: For portability, values are stored in Anglo-American units)
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
Ahoj!
Very nice. Maybe even too good for the task.
But I also "overdid it" with my avisos.
Borys
If the design is "too good", where would you make cuts?
Block coefficent 0.43?
Ahoj!
I was wondering about the belt - maybe 2 inches enough?, and the speed.
As to the speed and powerplant - I gave my avisos VTE's.
As to armour - I ladled the sides with 4 inch thick armour plates :), so ... "let him who be without sin cast the first stone ... "
:D
Borys
I thought a 0.43 BC was reasonable for a small, fast-ish cruiser. I can reduce the beam and increase to ~0.45, no doubt.