Iberia BB Design Study

[Guinness]

chamber and breech designs were a lot different, as was handling gear, etc. There were probably even slight differences in bore diameter between US and UK designs. Finally, of course, the US guns were from a previous era.

Still, if allies wanted to make an effort to standardize guns and shells at about the same time, I see no reason why that shouldn't work. In character though, the various ordnance departments of the various countries are all going to have deep-seated views on what design characteristics are best, and probably have a very difficult time coming to an agreement. The best chance is likely if each country sourced the guns themselves from the same place. Remember: large caliber naval guns aren't mass produced like tanks or airplanes, or even lighter artillery. It's hard enough for one manufacturer to produce a homogeneous production run of guns that all perform similarly enough when put to use. Doing that across many different nations in 1913 would be even more difficult, I'd think.

[miketr]

If we all using one gun design and ones licensed from the said design it would work otherwise I think not.  Or we would all have to declare we are going to use the same details when adopting / R&Ding a new gun.  At anyrate I wouldn't worry about the Peru BB's having 340mm weapons.  Long term...  whatever we build after this warships we might want to attempt to have the alliance move towards a more common design in terms of weapons, etc.  A common speed is best to hope for at this time.

[miketr]

If there is to be a min fleet speed of 22.5 knots for modern units figure I should update my GB which could be pressed into a BB escort in wartime.

GB-1916-B, Iberia Gun Boat laid down 1916 (Engine 1912)

Displacement:
   2,187 t light; 2,273 t standard; 2,753 t normal; 3,138 t full load

Dimensions: Length overall / water x beam x draught
   334.24 ft / 328.08 ft x 41.01 ft x 12.14 ft (normal load)
   101.88 m / 100.00 m x 12.50 m  x 3.70 m

Armament:
      3 - 5.91" / 150 mm guns in single mounts, 102.98lbs / 46.71kg shells, 1916 Model
     Breech loading guns in deck mounts with hoists
     on centreline ends, majority forward, 1 raised mount
      4 - 1.97" / 50.0 mm guns in single mounts, 3.81lbs / 1.73kg shells, 1916 Model
     Quick firing guns in deck mounts
     on side, all amidships
      2 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1916 Model
     Anti-aircraft guns in deck mounts
     on side, evenly spread, all raised mounts
      4 - 0.49" / 12.5 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1916 Model
     Machine guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 350 lbs / 159 kg
   Shells per gun, main battery: 150

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   2.95" / 75 mm   213.25 ft / 65.00 m   7.68 ft / 2.34 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.98" / 25 mm         -               -
   2nd:   0.98" / 25 mm         -               -

   - Armour deck: 1.97" / 50 mm, Conning tower: 5.91" / 150 mm

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 13,000 shp / 9,698 Kw = 22.67 kts
   Range 11,000nm at 10.00 kts
   Bunker at max displacement = 865 tons (67% coal)

Complement:
   189 - 247

Cost:
   £0.312 million / $1.248 million

Distribution of weights at normal displacement:
   Armament: 44 tons, 1.6 %
   Armour: 600 tons, 21.8 %
      - Belts: 206 tons, 7.5 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 14 tons, 0.5 %
      - Armour Deck: 355 tons, 12.9 %
      - Conning Tower: 25 tons, 0.9 %
   Machinery: 552 tons, 20.0 %
   Hull, fittings & equipment: 936 tons, 34.0 %
   Fuel, ammunition & stores: 566 tons, 20.6 %
   Miscellaneous weights: 55 tons, 2.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     4,542 lbs / 2,060 Kg = 44.1 x 5.9 " / 150 mm shells or 1.2 torpedoes
   Stability (Unstable if below 1.00): 1.28
   Metacentric height 2.0 ft / 0.6 m
   Roll period: 12.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.28
   Seaboat quality  (Average = 1.00): 1.35

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.590
   Length to Beam Ratio: 8.00 : 1
   'Natural speed' for length: 18.11 kts
   Power going to wave formation at top speed: 58 %
   Trim (Max stability = 0, Max steadiness = 100): 52
   Bow angle (Positive = bow angles forward): 15.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      22.97 ft / 7.00 m
      - Forecastle (20 %):   19.69 ft / 6.00 m
      - Mid (50 %):      11.48 ft / 3.50 m
      - Quarterdeck (15 %):   11.48 ft / 3.50 m
      - Stern:      11.48 ft / 3.50 m
      - Average freeboard:   14.62 ft / 4.46 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 80.2 %
      - Above water (accommodation/working, high = better): 131.4 %
   Waterplane Area: 9,749 Square feet or 906 Square metres
   Displacement factor (Displacement / loading): 131 %
   Structure weight / hull surface area: 60 lbs/sq ft or 295 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.92
      - Longitudinal: 2.00
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is excellent
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

[Jefgte]

I always like the concept for Gun Boat or Escort Cruiser.
The job for that ships is to protect BB Squadron from Torpedo Boats or Cruisers.
IMHO
- The speed is perhaps shorter for a 22kts BBs squadron, 25kts is probably better.
- 3x6" are just enough to engage a 30kts TB.
- the mixture of 50 & 75mm guns is not useful.
- 6x127 or 6x120 are perhaps more homogeneous in action


Jef  ;)

[miketr]

The 75's are AAA and the 50mm's are QF weapons.  I can't fit more 150's on the ship even if I ditch all the 50mm's; I could only if I did that and ditched all my misc weight.  What I could do is ditch the 50mm's for an equal number of 75's if I also ditch 13 tons of misc weight reducing that to 42 tons.

[miketr]

A rough draft drawing of my 350mm BB for 1917.  I am not really happy with the look of the secondaries.  There are some changes from the C1 design, the Q turret was raised above the main deck to assure there would be no interference with the secondaries.  Add more misc displacement.  The 1917 BB will mount 4 fire control mounts.

Two for the main guns (500 tons)
Two for the secondaries (200 tons)

For a massive weight investment of 700 tons.

The reason for this is because of what happened to SMS Juan de Austria at the battle of Crete when she lost fire control.   

BB-1917-C2, Iberia Battleship laid down 1917 (Engine 1916)

Displacement:
   27,834 t light; 29,501 t standard; 32,593 t normal; 35,067 t full load

Dimensions: Length overall / water x beam x draught
   650.00 ft / 650.00 ft x 100.00 ft x 27.00 ft (normal load)
   198.12 m / 198.12 m x 30.48 m  x 8.23 m

Armament:
      10 - 13.78" / 350 mm guns (5x2 guns), 1,308.20lbs / 593.39kg shells, 1917 Model
     Breech loading guns in turrets (on barbettes)
     on centreline, evenly spread, 3 raised mounts
      16 - 5.91" / 150 mm guns (8x2 guns), 102.98lbs / 46.71kg shells, 1917 Model
     Breech loading guns in deck mounts with hoists
     on side, all amidships
      8 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1917 Model
     Quick firing guns in deck mounts
     on side, evenly spread, all raised mounts
      8 - 0.49" / 12.5 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1917 Model
     Quick firing guns in deck mounts
     on side, evenly spread, all raised mounts
      4 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1917 Model
     Anti-aircraft guns in deck mounts
     on side, all amidships, all raised mounts - superfiring
   Weight of broadside 14,885 lbs / 6,752 kg
   Shells per gun, main battery: 120
   4 - 21.0" / 533.4 mm submerged torpedo tubes

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   13.0" / 330 mm   420.00 ft / 128.02 m   12.00 ft / 3.66 m
   Ends:   4.00" / 102 mm   230.00 ft / 70.10 m   11.00 ft / 3.35 m
   Upper:   4.00" / 102 mm   420.00 ft / 128.02 m   13.00 ft / 3.96 m
     Main Belt covers 99 % of normal length

   - Torpedo Bulkhead:
      1.50" / 38 mm   420.00 ft / 128.02 m   26.00 ft / 7.92 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   13.0" / 330 mm   9.00" / 229 mm      13.0" / 330 mm
   2nd:   1.00" / 25 mm         -               -
   3rd:   1.00" / 25 mm         -               -
   4th:   1.00" / 25 mm         -               -

   - Armour deck: 3.00" / 76 mm, Conning tower: 13.78" / 350 mm

Machinery:
   Coal and oil fired boilers, steam turbines,
   Direct drive, 3 shafts, 48,000 shp / 35,808 Kw = 22.54 kts
   Range 18,000nm at 10.00 kts
   Bunker at max displacement = 5,566 tons (67% coal)

Complement:
   1,212 - 1,576

Cost:
   £5.098 million / $20.390 million

Distribution of weights at normal displacement:
   Armament: 1,861 tons, 5.7 %
   Armour: 11,100 tons, 34.1 %
      - Belts: 4,209 tons, 12.9 %
      - Torpedo bulkhead: 606 tons, 1.9 %
      - Armament: 3,219 tons, 9.9 %
      - Armour Deck: 2,764 tons, 8.5 %
      - Conning Tower: 303 tons, 0.9 %
   Machinery: 1,904 tons, 5.8 %
   Hull, fittings & equipment: 12,067 tons, 37.0 %
   Fuel, ammunition & stores: 4,758 tons, 14.6 %
   Miscellaneous weights: 903 tons, 2.8 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     44,460 lbs / 20,167 Kg = 34.0 x 13.8 " / 350 mm shells or 7.3 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 6.0 ft / 1.8 m
   Roll period: 17.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 58 %
         - Recoil effect (Restricted arc if above 1.00): 0.58
   Seaboat quality  (Average = 1.00): 1.22

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.650
   Length to Beam Ratio: 6.50 : 1
   'Natural speed' for length: 25.50 kts
   Power going to wave formation at top speed: 45 %
   Trim (Max stability = 0, Max steadiness = 100): 48
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      24.00 ft / 7.32 m
      - Forecastle (20 %):   21.00 ft / 6.40 m
      - Mid (50 %):      17.00 ft / 5.18 m
      - Quarterdeck (15 %):   16.00 ft / 4.88 m
      - Stern:      16.00 ft / 4.88 m
      - Average freeboard:   18.32 ft / 5.58 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 84.6 %
      - Above water (accommodation/working, high = better): 138.2 %
   Waterplane Area: 49,794 Square feet or 4,626 Square metres
   Displacement factor (Displacement / loading): 106 %
   Structure weight / hull surface area: 186 lbs/sq ft or 906 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.98
      - Longitudinal: 1.10
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent
   Good seaboat, rides out heavy weather easily

[Guinness]

If you are packing that much FC, you're going to need bigger masts...

This grants me opportunity to ask a question: I always assumed that capital ship FC could control both primary and secondary batteries. Also, while the rangefinders, etc. may be located at masthead, the real brains of the FC is the plotting table/computer etc. which is usually below decks. Even if the masthead equipment was lost, less accurate data should still be able to be input into the plot from other sources (including rangefinders lower down). So what are the benefits from redundant FC arrangement? Could a 250t capital ship installation be backed up by a 100t cruiser installation maybe (ie, could a seperate secondary battery fire control system also control the main battery)?

Maybe an expert on the intent of the rules could comment.

At any rate, the secondaries:

Looking at your illustration, I suspect that you could group your secondaries into two more closely spaced groups on either beam to clear the blast interference from the main guns, even to the point where Q turret could come back down to the main deck.

[The Rock Doctor]

I've taken it for granted that the 250 t set controls all of the armament, not just the main battery.

[Borys]

You don't need 360 arc of fire for Q turret :)
Borys

[miketr]

If you are packing that much FC, you're going to need bigger masts...

Good point thank you...  I will see what I can come up with.

This grants me opportunity to ask a question: I always assumed that capital ship FC could control both primary and secondary batteries. Also, while the rangefinders, etc. may be located at masthead, the real brains of the FC is the plotting table/computer etc. which is usually below decks. Even if the masthead equipment was lost, less accurate data should still be able to be input into the plot from other sources (including rangefinders lower down). So what are the benefits from redundant FC arrangement? Could a 250t capital ship installation be backed up by a 100t cruiser installation maybe (ie, could a seperate secondary battery fire control system also control the main battery)?

Maybe an expert on the intent of the rules could comment.

All I know is what happened to SMS Juan de Austria. She took I assume a critcal hit and lost fire control forcing the guns to local control from the report.  I am taking steps to make sure that a golden BB won't be such an issue for my newest BB.  Also from what "little" I have read of WW1 fire control having additional fire control range finders was common for RN ships was common later in the war.  Since I have fewer ships I am taking steps to make sure that they can stay in the battle as long as possible as damage piles up.  So to make the ship totally blind would require four FC mounts to be taken out; odds are I assume the ship would be a wrecked hulk by that point.

At any rate, the secondaries:

Looking at your illustration, I suspect that you could group your secondaries into two more closely spaced groups on either beam to clear the blast interference from the main guns, even to the point where Q turret could come back down to the main deck.

Perhaps but I will also need some deck space for boats and launches.  Thats why Q  turret is set more towards the back to allow for a boat park forward of it.

My main issue is I just don't know how big to make the mounts for the 150's so I just guessed.

Thanks for the thoughts!

Michael

[miketr]

I've taken it for granted that the 250 t set controls all of the armament, not just the main battery.

I assumed as much myself but I want to be sure she could fight to the death.  In effect the ship is the result of Iberia's lessons from the Battle of Crete.

1) Beware of lost FC because of the golden BB
2) Torpedo Boats are the biggest threat at the end of a fight when one side has broken off.  By having additional Cruiser Scale FC mounts the BB is much more likely to have at least one director intact able to control the 150's (assuming they weren't wrecked) to attempt to kill the charging TBs/DDs.
2a) I have no idea how splitting fire would work but with all the FC mounts I assume it wouldn't be an issue for this design.

You don't need 360 arc of fire for Q turret

It won't a boat park is to go in forward of it.  270+ arc will work just fine.

Michael

[Guinness]

FC: I think pretty much every nation that developed FC had redundant range finders which could also transmit bearing. Most did not have a second FC plot though. I think the easiest way to disable FC would be to sever the connections between the plot and the range and bearing transmittes above decks, or just take a hit in the FC plot itself. To get true redundancy, you'd need two FC plots, which even on big ships like these will be difficult to fit in, I'd expect.

150mm mounts: what you need to know here first is the overall length of your guns. For instance, the US 6"L53 was 325 inches long, or slightly more than 27 feet. If the mount is open backed, that's going to be your total length. If it is an enclosed gunhouse, you need to add the distance behind the breech needed to operate the gun. In my twin 5.5" mount, I used 7 feet (which was the product of me ballparking it after looking at pictures of a bunch of twin 6" gunhouses). So in that instance, the whole mount is 31.5 feet long, from muzzle to the back of the gunhouse.

[miketr]

Thank you that is most helpful on the secondaries...   Right now they are 18 feet long so they are as I feared far too small.  I will add that to my list of chanages you have been most helpful sir.

As to FC... WW2 ships had fully redundant FC centers no clue when that came into being.  Anyone have a clue what the setup on Rodney and Nelson was?  All I am looking for is some type of bonus vs. critical blinding my BB with a lone lucky hit.  Things don't need to be super detailed and I doubt I can afford this type of Misc Weight allocation to all ships.  Especially smaller ships.

Michael

[Guinness]

Here's a good piece from 1918 about fire control in the 1918 USN. I suspect there's not much here that most of us don't already know, but it's a good refresher:

http://www.gwpda.org/naval/usnfirec.htm

As to the question at hand: The battle report reads: "Mahmudiye demolishes Juan de Austria's primary range finder and fire control station with a lucky hit and, despite the range, begins outshooting the newer, larger Austrian ship."

So, that would be bad. I read that and understand it to mean that the range finder and fire control station were likely located in close proximity to each other. I imagine that's because the same practice was followed here that the USN followed during the period, with the FC station in the conning tower with the ship's control station. This was a practice followed in other navies at the time as well, including the German Navy. Often the preferred range finder would be located close by as well.

So, in this case, the critical loss isn't just the rangefinder (in fact I'd argue that is minor, since its likely any FC equipped BB we're building now has other rangefinders in the turrets or elsewhere). It's the loss of the FC station itself, and the men who occupied it, including the FC officer. It would not be expensive in terms of weight to provide other locations where the work of this station can be done. What a navy would need to do though is train for its loss, and have that training kick in immediately upon realization of its loss. There would still be a loss of efficiency though, as central weapons control is shifted to another location (most likely the plot, I expect), as wherever the backup location is, I expect it would be away from ship's control (ie the conning tower), so the easy verbal coordination that was possible between those steering the ship and those firing the guns will be lost.

Does that make sense? In other words, I think the problem of preparing for an FC loss is one best handled via training (ie via a very little bit of role playing), and not one of ship's architecture, necessarily. If you want to handle it through architecture though, maybe a thicker conning tower might fulfill your intention?

[P3D]

To destroy the (primary) fire control station a direct hit on the CT would've been necessary. A ships should have more rangefinders, so taking the main one out would force the FC to rely on a second rangefinder - e.g. one located in a turret.

Most probably the system Rocky used had a single item reserved for FC on the hit location tables, and one hit there means the destruction of the ship's FC for simplicity.