Shipbucket

Back in 2007(?) I posted a design for a "small dreadnought"- the very first drawing I posted here. I was given a lot of useful feedback which allowed me to refine my original concept, but sadly real life intervened before I was able to finish the project.

Until now!





The second drawing is an attempt to envisage how the design might have been modernised, a la the QE class. While I like the overall feel, I do have some concerns though. The crane is rather too large for just handling the ship's boats and rather gets in the way of things, but after trawling through drawings of RL RN ships I couldn't find one of the period that I felt would work any better. I'm also a little concerned about the second 4.5 forward mounting and wonder if it doesn't make things too cramped.

I haven't tried creating the modernised version in SS yet, but this is the design as originally built:

B1 Class, Yasutomi Small Dreadnought laid down 1911

Displacement:
17,356 t light; 18,513 t standard; 19,234 t normal; 19,812 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(500.00 ft / 500.00 ft) x 88.00 ft x (25.50 / 26.13 ft)
(152.40 m / 152.40 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 280.00 ft / 85.34 m 12.00 ft / 3.66 m
Ends: 4.00" / 102 mm 219.98 ft / 67.05 m 12.00 ft / 3.66 m
Upper: 8.00" / 203 mm 280.00 ft / 85.34 m 9.00 ft / 2.74 m
Main Belt covers 86 % of normal length

- Torpedo Bulkhead - Additional damage containing bulkheads:
3.00" / 76 mm 280.00 ft / 85.34 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: 4.00" / 102 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, 29,012 shp / 21,643 Kw = 21.13 kts
Range 5,500nm at 10.00 kts
Bunker at max displacement = 1,299 tons

Complement:
816 - 1,061

Cost:
£1.508 million / $6.031 million

Distribution of weights at normal displacement:
Armament: 1,697 tons, 8.8 %
- Guns: 1,697 tons, 8.8 %
Armour: 7,637 tons, 39.7 %
- Belts: 3,185 tons, 16.6 %
- Torpedo bulkhead: 761 tons, 4.0 %
- Armament: 1,560 tons, 8.1 %
- Armour Deck: 1,945 tons, 10.1 %
- Conning Tower: 186 tons, 1.0 %
Machinery: 1,177 tons, 6.1 %
Hull, fittings & equipment: 6,844 tons, 35.6 %
Fuel, ammunition & stores: 1,878 tons, 9.8 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
37,473 lbs / 16,997 Kg = 30.5 x 13.5 " / 343 mm shells or 7.4 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 %): 80 %
- Recoil effect (Restricted arc if above 1.00): 0.78
Seaboat quality (Average = 1.00): 1.61

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: 5.68 : 1
'Natural speed' for length: 22.36 kts
Power going to wave formation at top speed: 49 %
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: 27.00 %, 25.00 ft / 7.62 m, 24.00 ft / 7.32 m
- Forward deck: 39.00 %, 24.00 ft / 7.32 m, 24.00 ft / 7.32 m
- Aft deck: 17.00 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Quarter deck: 17.00 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Average freeboard: 21.39 ft / 6.52 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 71.6 %
- Above water (accommodation/working, high = better): 162.0 %
Waterplane Area: 32,181 Square feet or 2,990 Square metres
Displacement factor (Displacement / loading): 113 %
Structure weight / hull surface area: 169 lbs/sq ft or 825 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.91
- Longitudinal: 2.34
- Overall: 1.00
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

As always, comments and suggestions are appreciated!

Hi Yasutomi,

The drawing looks nice, but in view of the greater threat from torpedoes (both sub-lauched and air-dropped) wouldn't the ship have had bulges added too? I seem to recall that a lot of the WWI ships that were still in service got that sort of treatment, even at the cost of taking them out of the line of battle.

Regards,
Adam

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Hi Adam!

I did consider adding bulges (and may yet retro-fit them), but persuaded myself against the idea for a couple of reasons. Firstly, the original design was quite well protected from underwater damage, with an extensive TBH set a fair distance inboard. Secondly, I felt that bulges would exacerbate the design's major weakness- indifferent speed. As designed, it can only reached a touch over 21 kts and even with superior engines, bulges are going to make for an even less efficient hull.

On the other hand...bulges may help with all that topweight I seem to have added...

Is it me or is it carrying quite a bit of deck thickness for a 1914 design ? (4 inch)

and the belt is only 'Main Belt covers 86 % of normal length' ?

I would have through you will need to bulge to cover the extra weight, can you change the stern or bow as the Italians did ?

The deck armour is certainly generous, although not unthinkable (didn't the König have up to 3.9" over vital spaces?).

I was a little confused with the 'Main Belt covers 86 % of normal length', but- and perhaps someone can correct me if I'm wrong- SS seems to define normal length as 65% of the total, regardless of the ship's configuration. I have no idea whether there is some engineering point behind this. The B1 class has a long forecastle to improve seakeeping, which is why the main belt only extends over 56% of the length- although apparently that is sufficient to completely enclose the vital areas.

I will look into adding bulges, as I do agree that stability is a concern (although the original design did have reasonable margins and I am deleting the conning tower). Changing the bow and/or stern is possible, although I've tried to stick to the formula of British rebuilds, which didn't seem to do this. If I recall correctly, the Italian Dorias and Cavours were substantially lengthed; the Kongos certainly were.

SS Report for the modernised version, without bulges:

B1 Class, Yasutomi Small Dreadnought laid down 1911 (Engine 1937)

Displacement:
17,609 t light; 18,770 t standard; 19,234 t normal; 19,606 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(500.00 ft / 500.00 ft) x 88.00 ft x (25.50 / 25.90 ft)
(152.40 m / 152.40 m) x 26.82 m x (7.77 / 7.90 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
16 - 4.50" / 114 mm 45.0 cal guns - 55.01lbs / 24.95kg shells, 150 per gun
Quick firing guns in deck and hoist mounts, 1937 Model
8 x 2-gun mounts on sides, evenly spread
16 - 1.57" / 40.0 mm 39.0 cal guns - 1.86lbs / 0.84kg shells, 150 per gun
Anti-air guns in deck mounts, 1923 Model
2 x 2 row octuple mounts on sides, forward deck aft
2 raised mounts
Weight of broadside 9,310 lbs / 4,223 kg

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 12.0" / 305 mm 280.00 ft / 85.34 m 12.00 ft / 3.66 m
Ends: 4.00" / 102 mm 219.98 ft / 67.05 m 12.00 ft / 3.66 m
Upper: 8.00" / 203 mm 280.00 ft / 85.34 m 9.00 ft / 2.74 m
Main Belt covers 86 % of normal length

- Torpedo Bulkhead - Additional damage containing bulkheads:
3.00" / 76 mm 280.00 ft / 85.34 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: 2.00" / 51 mm 1.00" / 25 mm 1.00" / 25 mm

- Armoured deck - multiple decks:
For and Aft decks: 5.00" / 127 mm
Forecastle: 1.00" / 25 mm Quarter deck: 1.00" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 39,999 shp / 29,840 Kw = 22.92 kts
Range 5,500nm at 10.00 kts
Bunker at max displacement = 836 tons

Complement:
816 - 1,061

Cost:
£1.538 million / $6.152 million

Distribution of weights at normal displacement:
Armament: 1,774 tons, 9.2 %
- Guns: 1,774 tons, 9.2 %
Armour: 7,848 tons, 40.8 %
- Belts: 3,185 tons, 16.6 %
- Torpedo bulkhead: 761 tons, 4.0 %
- Armament: 1,508 tons, 7.8 %
- Armour Deck: 2,393 tons, 12.4 %
Machinery: 1,109 tons, 5.8 %
Hull, fittings & equipment: 6,878 tons, 35.8 %
Fuel, ammunition & stores: 1,625 tons, 8.4 %
Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
37,167 lbs / 16,859 Kg = 30.2 x 13.5 " / 343 mm shells or 7.3 torpedoes
Stability (Unstable if below 1.00): 1.18
Metacentric height 5.6 ft / 1.7 m
Roll period: 15.6 seconds
Steadiness - As gun platform (Average = 50 %): 66 %
- Recoil effect (Restricted arc if above 1.00): 0.74
Seaboat quality (Average = 1.00): 1.32

Hull form characteristics:
Hull has rise forward of midbreak,
a normal bow and a cruiser stern
Block coefficient (normal/deep): 0.600 / 0.602
Length to Beam Ratio: 5.68 : 1
'Natural speed' for length: 22.36 kts
Power going to wave formation at top speed: 54 %
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: 27.00 %, 25.00 ft / 7.62 m, 24.00 ft / 7.32 m
- Forward deck: 39.00 %, 24.00 ft / 7.32 m, 24.00 ft / 7.32 m
- Aft deck: 17.00 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Quarter deck: 17.00 %, 16.00 ft / 4.88 m, 16.00 ft / 4.88 m
- Average freeboard: 21.39 ft / 6.52 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 71.8 %
- Above water (accommodation/working, high = better): 162.0 %
Waterplane Area: 32,181 Square feet or 2,990 Square metres
Displacement factor (Displacement / loading): 111 %
Structure weight / hull surface area: 171 lbs/sq ft or 833 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.91
- Longitudinal: 2.33
- Overall: 1.00
Excellent machinery, storage, compartmentation space
Excellent accommodation and workspace room
Good seaboat, rides out heavy weather easily

Instead of fitting smaller, lighter engines producing the same power (which would make stability issues even more acute), I've opted to increase power from 29,000 to 40,000 hp: according to SS, the new engines would occupy roughly the same space as the old and would raise speed to just under 23 kts, although I'm always sceptical of SS's accuracy in such matters.

Deck armour has been increased to 5' and the conning tower deleted; the 6' guns have been replaced by 16 4.5' QF and 2 Octuple 40mm AA. Seakeeping and steadiness aren't quite as good, but are still more than adequate.

The main armor belt usually extends up to 5-10 meters in front/back of the barbettes.

That's going to be a real problem.

According to SS, the main belt is already significantly longer than necessary to protect the vitals. However, I can't group turrets and machinery any closer.

I'll have to rework the numbers, but perhaps reducing the AD thickness to 3' (closer to RL practice) will allow a longer belt.

What are the actual pre-requisites for it to be a small dreadnought? You might be able to tweak some things size wise if you can expand it a little.

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Who is it for ? and any backstory would be nice as well. (looks very RN apart from the flag so maybe a colony ?)

JSB