Okay, so I’ve been playing with the cruiser design for the last couple of days, and Sharon and I are flying to Des Moines this morning (leaving Greenville at six a.m.), so since I was getting up and packing early, I spent the last couple of hours playing with the River-class ironclads gunboats. It was interesting to see how close they came, in a lot of ways, in my original design to what the software produced. In fact, the actual tonnages and displacements are very, very close, but I had significantly overestimated the coal consumption, assuming that the software gets it right. It worked out pretty well, anyway, because I’d obviously underestimated weights somewhere else. They came out a little slower than my maximum speed estimate (I could’ve gotten them up to my original numbers, but while they probably would have survived standard brown water conditions in that configuration, they probably wouldn’t have survived the voyage from Charis to Siddarmark, so I went with the lower-speed) but with a lot more endurance.
Anyway, here they are:
River-class ironclad gunboat
Imperial Charisian Navy
River barge conversion
Delthak Dockyard, 895
Displacement:
Light: 1,058 tons
Standard: 1,323 tons
Normal: 1,386 tons
Full load: 1,436 tons
Dimensions:
Length (overall / waterline): 140’
Beam: 40’
Draft (normal): 10’
Draft (deep) 10/4”
Armament:
24 x 30-pdr ML smoothbores, 3 x 11 x 3 (solid shot = 32 pounds; HE shell = 18 pounds; 250 rounds/gun)
Weight of broadside (shot): 352 pounds
Weight of broadside (shell): 198 pounds
Ahead/Astern (shot): 96 pounds
Ahead/Astern (shell): 54 pounds
Armor:
Casemate: thickness = 3”; length= 126’; height = 12’; inclined 16˚
Hull (fwd/aft of casemate): thickness = 3”; length = 14’; height = 6’; no slope
Casemate roof & decks: 1”
Conning Tower: 6”; no slope
Machinery:
Coal fired boilers, double-expansion engines, direct drive, 2 shafts, 65.21 sdp (1,663 shp) = 15 knots (13 Old Earth knots)
Range: 1,800 nm @ 9.5 knots (8.25 Old Earth knots)
3,500 nm @ 7 knots (6 Old Earth knots)
Bunker: (normal): 62 tons
Bunker (maximum): 112 tons
Complement: 197
Cost: CM 126,000
Distribution of weights at normal displacement:
Armament: 140 tons, 10.1 %
Armour: 334 tons, 24.1 %
Machinery: 241 tons, 17.4 %
Hull, fittings & equipment: 343 tons, 24.7 %
Fuel, ammunition & stores: 328 tons, 23.7 %
Miscellaneous weights: 0 tons, 0.0 %
Overall survivability and seakeeping ability:
Survivability (penetrating hits to sink ship): 17 x 30-pounder shells
Stability (Unstable if below 1.00): 1.66
Metacentric height 2.9 ft / 0.9 m
Roll period: 9.8 seconds
Seaboat quality (Average = 1.00): 0.85
Hull form characteristics:
Hull has low forecastle, low quarterdeck , a vertical bow and a round stern
Block coefficient (normal/deep): 0.866 / 0.868
Length to Beam Ratio: 3.50 : 1
'Natural speed' for length: 11.83 kts
Power going to wave formation at top speed: 66 %
Freeboard:
Foredeck: 4’ (length = 7’)
Casemate: 10’ (length = 126’)
Average: 8.8’
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 104.8 %
- Above water (accommodation/working, high = better): 88.3 %
Waterplane Area: 5,238 Square feet or 487 Square metres
Displacement factor (Displacement / loading): 108 %
Structure weight / hull surface area: 64 lbs/sq ft or 310 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.78
- Longitudinal: 4.63
- Overall: 0.93
Caution: Hull subject to strain in open-sea
Adequate machinery, storage, compartmentation space
Cramped accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather.
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River-class ironclad gunboat (refit)
Imperial Charisian Navy
River barge conversion
Delthak Dockyard, 895
Displacement:
Light: 1,172 tons
Standard: 1,430 tons
Normal: 1,493 tons
Full load: 1,543 tons
Dimensions:
Length (overall / waterline): 140’
Beam: 40’
Draft (normal): 10’0.5”
Draft (deep) 10’4.5”
Armament:
20* x 6”/45 M895 BL guns (3 x 9 x 3) (AP shell = 115 pounds; 250 rounds/gun)
Weight of broadside: 1,035 pounds
Ahead/Astern: 345 pounds
Broadsides reduced by 2 guns each beause of weight differential between weapons.
Armor:
Casemate: thickness = 3”; length= 126’; height = 12’; inclined 16˚
Hull (fwd/aft of casemate): thickness = 3”; length = 14’; height = 6’; no slope
Casemate roof & decks: 1”
Conning Tower: 6”; no slope
Machinery:
Coal fired boilers, double-expansion engines, direct drive, 2 shafts, 65.21 sdp (1,663 shp) = 15 knots (13 Old Earth knots)
Range: 1,800 nm @ 9.5 knots (8.25 Old Earth knots)
3,500 nm @ 7 knots (6 Old Earth knots)
Bunker: (normal): 62 tons
Bunker (maximum): 112 tons
Complement: 157
Cost: CM 162,000
Distribution of weights at normal displacement:
Armament: 247 tons, 17.8 %
Armour: 334 tons, 24.1 %
Machinery: 241 tons, 17.4 %
Hull, fittings & equipment: 343 tons, 24.7 %
Fuel, ammunition & stores: 328 tons, 23.7 %
Miscellaneous weights: 0 tons, 0.0 %
Overall survivability and seakeeping ability:
Survivability (penetrating hits to sink ship): 10 x 6” AP
Stability (Unstable if below 1.00): 1.66
Metacentric height 2.9 ft / 0.9 m
Roll period: 9.8 seconds
Seaboat quality (Average = 1.00): 0.85
Hull form characteristics:
Hull has low forecastle, low quarterdeck , a vertical bow and a round stern
Block coefficient (normal/deep): 0.866 / 0.868
Length to Beam Ratio: 3.50 : 1
'Natural speed' for length: 11.83 kts
Power going to wave formation at top speed: 66 %
Freeboard:
Foredeck: 4’ (length = 7’)
Casemate: 10’ (length = 126’)
Average: 8.8’
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 104.8 %
- Above water (accommodation/working, high = better): 88.3 %
Waterplane Area: 5,238 Square feet or 487 Square metres
Displacement factor (Displacement / loading): 108 %
Structure weight / hull surface area: 64 lbs/sq ft or 310 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.78
- Longitudinal: 4.63
- Overall: 0.93
Caution: Hull subject to strain in open-sea
Adequate machinery, storage, compartmentation space
Cramped accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather
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Delthak II – class broadside ironclad gunboat
Imperial Charisian Navy
Tellesberg, King’s Harbor, & Delthak DYs
All laid down 895 YoG
All launched & Commissioned: 896 YoG
Displacement:
Light: 1,181 tons
Standard: 1,465 tons
Normal: 1,529 tons
Full Load: 1,580 tons
Dimensions:
Length (waterline): 160’
Length (overall): 160’
Beam: 40’
Draft (normal): 10’
Draft (full): 10’3”
Armament:
22 x 6”/45 M895 BL guns 3 x 11 x 3 (115-pound AP shell; 200/gun)
Weight of broadside (13 guns): 1,495 pounds
Weight fore or aft (3 guns): 345 pounds
Armor:
Casemate: thickness= 3”; length = 146’; height = 14’; inclined 16˚
Freeboard fore & aft: thickness=3”; length = 14’; height = 4’
Casemate roof/decks: 1”
Conning tower: 6” (no slope)
Machinery:
Coal fired boilers, double-expansion engines, direct drive, 2 shafts, 45 sdp (1,147 shp) = 14 knots (12.2 Old Earth knots)
Range 1,800nm at 9.5 knots (8.25 Old Earth knots)
Range 3,500 nm at 5.7 knots (5 Old Earth knots)
Bunker (normal): 59 tons
Bunker (max displacement): 115 tons
Complement: 158
Cost: CM 168,000
Distribution of weights at normal displacement:
Guns: 281 tons, 18.4 %
Armor: 286 tons, 18.7 %
Machinery: 166 tons, 10.9 %
Hull, fittings & equipment: 448 tons, 29.3 %
Fuel, ammunition & stores: 348 tons, 22.7 %
Overall survivability and seakeeping ability:
Survivability (penetrating hits to sink ship): 17 x 6”/45
Stability (Unstable if below 1.00): 1.81
Metacentric height 3.3 ft / 1.0 m
Roll period: 9.2 seconds
Steadiness as gun platform (Average = 50 %): 68 %
Seaboat quality (Average = 1.00): 1.35
Hull form characteristics:
Hull has low forecastle, low quarterdeck , a normal bow and a round stern
Block coefficient (normal/deep): 0.836 / 0.838
Length to Beam Ratio: 4.00 : 1
'Natural speed' for length: 14.6 knots (12.65 Old Earth knots)s
Power going to wave formation at top speed: 57 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = length of deck as a percentage of waterline length):
- Forecastle: 10.00 %, 4.00 ft
- Forward deck: 30.00 %, 10.00 ft
- Aft deck: 50.00 %, 10.00 ft
- Quarter deck: 10.00 %, 4.00 ft
- Average: 8.80 ft
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 105.1 %
- Above water (accommodation/working, high = better): 91.7 %
Waterplane Area: 5,823 Square feet
Displacement factor (Displacement / loading): 100 %
Structure weight / hull surface area: 82 lbs/sq ft
Hull strength (Relative):
- Cross-sectional: 1.02
- Longitudinal: 4.66
- Overall: 1.19
Adequate machinery, storage, compartmentation space
Adequate accommodation and workspace room
Good seaboat, rides out heavy weather easily
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I think the biggest surprise I got was when the Delthak IIs, the purpose-built ironclads, ended up rated as a “good seaboat, rides out heavy weather easily.” I expected to improve their seakeeping ability when I made them 20 feet longer (which will make them less useful than the Rivers on the older canals) and settled for lower-power engines (if you remember, folks were reflecting that the Rivers were over-powered), but I didn’t expect as much improvement as I got. Mind you, I doubt anyone is going to enjoy getting through a storm at sea in one of these, but they probably won’t panic at the mere thought of facing one.
I’m also fiddling around with a Shan-wei-class superdreadnought mounting 10 x 16”/45 firing the USN’s superheavy shell. It’s looking like coming out around 70-75,000 tons standard displacement with oil-fired boilers and geared turbines. Of course, that’s providing Montana-style underwater protection on the theory that while it probably won’t have to deal with torpedoes, it might have to deal with a fairly serious mine threat by the time they were laid down . . . assuming, of course, that any such monstrosity might ever be built . . .