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Would you not want to go with a weaker faster ship ?
Even 12 inch guns will work if all you are going to fight is 2nd class colonial fleets and you will lose anyway v a first class dreadnought, so something fast and light looks better ?

Say 8 x 12 inch and as fast as possible (to out run what it cant fight).

JSB

That sounds awfully like a battlecruiser! But to be fair I do sort of agree with the idea as I mentioned earlier.
Glad to have been of assistance

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AU Projects: | Banbha et al. | New England: The Divided States
Blood and Fire

keep in mind that machinery weights are most of the time not directly scalable, unless you scale with parts (for example, use an lesser amount of the same boilers and turbines)

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Drawings are credited with J.Scholtens
I ask of you to prove me wrong. Not say I am wrong, but prove it, because then I will have learned something new.
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I specifically didn't want to go down that route with this project!

To be quite honest, I am far from convinced that the "outrun what it can't fight" philosophy is sound. Even at the time, it would be readily apparent that technology is advancing rapidly and a ship designed along those lines will likely be facing vessels able to outrun and outfight it within a few years- as the German's discovered with their Deutschlands. Trying to build such a ship on a budget is even more of a fool's errand as high speed equals size and expense.

My strategy therefore was to go the other way: a reasonably well-armed and armoured ship able to deter, if not outfight, existing first-class battleships. As I tried to explain earlier, it's all about forcing your opponent to risk a more expensive ship against you than it would like!
Oh, I am...but in the absence of a detailed breakdown of the sizes and weights of the various components, I'm forced to rely on very rough guesstimates!

If I recall correctly, QE had 24 Yarrow boilers (oil fired) and Revenge 18 (oil and coal?), so 21, with reasonably powerful engines, would seem a reasonable compromise for the Tambora.

The B1 design (which, I have to say, I'm thinking of reworking again) would only need 15, I reckon.

Having discovered some layout drawings of HMS Erin, which seem reasonably plausible to me, I've returned to the B1 design:



B1 Class, Yasutomi Small Dreadnought laid down 1911

Displacement:
17,837 t light; 19,004 t standard; 19,734 t normal; 20,319 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(513.00 ft / 513.00 ft) x 88.00 ft x (25.50 / 26.12 ft)
(156.36 m / 156.36 m) x 26.82 m x (7.77 / 7.96 m)

Armament:
6 - 13.50" / 343 mm 45.0 cal guns - 1,400.00lbs / 635.03kg shells, 150 per gun
Breech loading guns in turret on barbette mounts, 1911 Model
3 x 2-gun mounts on centreline ends, majority aft
1 raised mount aft - superfiring
8 - 6.00" / 152 mm 45.0 cal guns - 108.00lbs / 48.99kg shells, 150 per gun
Breech loading guns in casemate mounts, 1911 Model
8 x Single mounts on sides, evenly spread
8 hull mounts in casemates- Limited use in heavy seas
Weight of broadside 9,264 lbs / 4,202 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 12.0" / 305 mm 345.00 ft / 105.16 m 12.00 ft / 3.66 m
Ends: 4.00" / 102 mm 167.99 ft / 51.20 m 12.00 ft / 3.66 m
Upper: 8.00" / 203 mm 345.00 ft / 105.16 m 9.00 ft / 2.74 m
Main Belt covers 103 % of normal length

- Torpedo Bulkhead - Additional damage containing bulkheads:
3.00" / 76 mm 345.00 ft / 105.16 m 24.50 ft / 7.47 m
Beam between torpedo bulkheads 70.00 ft / 21.34 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 12.0" / 305 mm 8.00" / 203 mm 10.0" / 254 mm
2nd: 8.00" / 203 mm - -

- Armoured deck - multiple decks:
For and Aft decks: 3.00" / 76 mm
Forecastle: 1.00" / 25 mm Quarter deck: 1.00" / 25 mm

- Conning towers: Forward 12.00" / 305 mm, Aft 0.00" / 0 mm

Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 26,503 shp / 19,771 Kw = 20.61 kts
Range 5,451nm at 10.00 kts
Bunker at max displacement = 1,314 tons

Complement:
832 - 1,082

Cost:
£1.510 million / $6.042 million

Distribution of weights at normal displacement:
Armament: 1,697 tons, 8.6 %
- Guns: 1,697 tons, 8.6 %
Armour: 7,896 tons, 40.0 %
- Belts: 3,567 tons, 18.1 %
- Torpedo bulkhead: 938 tons, 4.8 %
- Armament: 1,560 tons, 7.9 %
- Armour Deck: 1,641 tons, 8.3 %
- Conning Tower: 189 tons, 1.0 %
Machinery: 1,076 tons, 5.5 %
Hull, fittings & equipment: 7,169 tons, 36.3 %
Fuel, ammunition & stores: 1,897 tons, 9.6 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
40,285 lbs / 18,273 Kg = 32.7 x 13.5 " / 343 mm shells or 8.4 torpedoes
Stability (Unstable if below 1.00): 1.19
Metacentric height 5.7 ft / 1.7 m
Roll period: 15.5 seconds
Steadiness - As gun platform (Average = 50 %): 87 %
- Recoil effect (Restricted arc if above 1.00): 0.82
Seaboat quality (Average = 1.00): 1.75

Hull form characteristics:
Hull has rise forward of midbreak,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0.600 / 0.603
Length to Beam Ratio: 5.83 : 1
'Natural speed' for length: 22.65 kts
Power going to wave formation at top speed: 47 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): -8.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.47 %, 25.50 ft / 7.77 m, 24.00 ft / 7.32 m
- Forward deck: 44.74 %, 24.00 ft / 7.32 m, 24.00 ft / 7.32 m
- Aft deck: 22.51 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Quarter deck: 12.28 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Average freeboard: 21.34 ft / 6.50 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 67.8 %
- Above water (accommodation/working, high = better): 161.2 %
Waterplane Area: 33,018 Square feet or 3,067 Square metres
Displacement factor (Displacement / loading): 116 %
Structure weight / hull surface area: 172 lbs/sq ft or 838 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 2.31
- Overall: 1.03
Excellent machinery, storage, compartmentation space
Excellent accommodation and workspace room
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

The main change is the length- 513 feet. This provides just about enough space to fit everything without wasted space. I've also limited the power to 26,500 shp- the same as Erin; although SS says I can install more, I'd rather err on the side of caution, not least as these drawings demonstrate (hopefully) that Erin's machinery will fit:





I can now say with some confidence that the B1 would have fifteen oil-fired boilers- the same number as Erin- but two instead of four turbines. SS estimates the 26,500 shp (I'm assuming shp will be similar?) would be good for 20.6 kts, but I wonder if some tweaking could allow it to reach the target speed of 21 kts.

My design has less beam (by 3 feet) and draught (by 2.5 feet) than Erin; would that ruin my assumptions? I can't see how it would but a second opinion is always nice.

The comparison with Jabba's drawing also demonstrates that once I finalise all these technical details, I really need to go back and improve the aesthetics of my drawing!

doesn't look too bad. you don't sacrifice survivability, but you will loose power if you do not use bigger turbines then those on the erin, watch out for that. another option is to keep 4 propellers.
the shorter length may result in an a bit lower speed on the same power as the erin, was that indeed the case? if it is, it might be a good idea to lengthen the bow and stern a bit, making the shape more efficient and the waterline longer, creating a ship that might go over that 21 knots or even faster, on nearly the same displacement.
it might be good to have higher funnels, the 'pull' of these also influences the power of the boiler.

other then that, I can only say, keep experimenting a bit, you are thinking along the right ways for ship design

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Drawings are credited with J.Scholtens
I ask of you to prove me wrong. Not say I am wrong, but prove it, because then I will have learned something new.
Shipbucket Wiki admin

When I first posted this design back in 2011, it had four shafts; I was advised to reduce that to two...which I did!

With direct-linked turbines, I'm guessing there's no way to couple two turbines to one shaft? Or are there more powerful turbine designs that are wider but no longer? Either way, I'd like to leave a sufficient margin of space to allow for the installation of new geared turbines during the refit.
I've been playing around with this on SS. Extending the bow by 10 feet and the stern by 7, for a total waterline length of 530 feet, actually reduces the calculated speed...which seems to run contrary to the idea that a longer hull is inherently faster. However...Erin is an example ship on SS3b2 (I'm using b3) and the program puts the installed power at 29,633 hp. Now unless the discrepancy has something to do with the difference between hp and shp, it seems that SS is overestimating the power required for a given speed (I reckon whoever created the example ship used Erin's calculated maximum speed as the basis for the machinery weights, rather than the installed power).

If I use the hp figure for HMS Erin in the example file, the speed of my design magically jumps to just over 21 kts. In other words...I think I need to take SS' figures with a pinch of salt on this one!
Good point!
Thanks, Ace!

A couple of revised drawings:


Design A: 4 shafts and raised funnels


Design B: 530' version with lengethened bow and stern

- "With direct-linked turbines, I'm guessing there's no way to couple two turbines to one shaft? Or are there more powerful turbine designs that are wider but no longer? Either way, I'd like to leave a sufficient margin of space to allow for the installation of new geared turbines during the refit."
that depends on the erin machinery. it is possible to fit 2 turbines to one shaft (many cruisers did just that during WW2) but I do not know if this was already done on the dreadnought machinery. also, seeing that a turbine set was often an setup of low and high pressure turbines, there might be some trouble there too. the last trouble is in the development of propellers that could take the power to the water with maximum efficiency, you should find a ship of the era with twice the engine power and 4 propellers or one with the same engine power on 2 to check if that works.

- you always need to take springsharp with a pinch of salt. that said:
* lengthening a ship to make it faster doesn't always work. there is some kind of ideal length for a speed, in which case it has the lowest resistance. lengthening a ship towards this ideal length gives it less required power, but away from it......
* on the other hand, lengthening a ship gives the ship a larger wet surface which gives more plate friction. plate friction and wave friction are the main resistance factors, plate friction is enlarged by lengthening the ship while wave friction is (to some limit) lowered.

_________________
Drawings are credited with J.Scholtens
I ask of you to prove me wrong. Not say I am wrong, but prove it, because then I will have learned something new.
Shipbucket Wiki admin