Vilnius Union Ships, 1930+: The Good, The Bad, and the Unseaworthy

[The Rock Doctor]

I know, right?

The next pressing business is to go into Paint and decide what my forthcoming DP mounts look like.

[Jefgte]

I like German 105/65 design

http://www.navweaps.com/Weapons/WNGER_41-65_skc33.php

[The Rock Doctor]

It looks cool, but I need something better waterproofed in practice. 

[TacCovert4]

British frying pan mounts?

My 120s are in the US 5in/51 configuration.  My 90s are in the German configuration.  And then I have the R2FU of my 40mm gatling aa...

[The Rock Doctor]

First draft of the A-class torpedo-boats to begin construction in 1931.

At heart it's a stretched Z-class boat, but:

-There is about 10% more range.  This works out to about 5,500 nm @ 15 knots, not counting geared drive efficiency.

-The main battery is DP, which are heavier, fully enclosed mounts compared to previous low-angle 130/45s.

-Eight torpedoes rather than six.

-There's a bit more speed and miscellaneous weight.  I had hope to add enough to allow for a future radar installation but can't do that if I need 25t for it.  As it is, the sketch shows my take on a Huelsmeyer device, just ahead of the forward rangefinder.

-Stylistically, the funnels are taller and capped to improve the flow of exhaust fumes away from useful bits of the ship. 

Enter ship name, Enter country Enter ship type laid down 1931

Displacement:
   2,160 t light; 2,288 t standard; 2,603 t normal; 2,855 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (406.35 ft / 393.70 ft) x 37.40 ft x (15.09 / 16.06 ft)
   (123.86 m / 120.00 m) x 11.40 m  x (4.60 / 4.89 m)

Armament:
      4 - 5.12" / 130 mm 45.0 cal guns - 67.62lbs / 30.67kg shells, 400 per gun
     Dual purpose guns in deck and hoist mounts, 1931 Model
     4 x Single mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
      4 - 1.97" / 50.0 mm 60.0 cal guns - 4.19lbs / 1.90kg shells, 1,500 per gun
     Anti-air guns in deck mounts, 1931 Model
     2 x Twin mounts on sides, forward deck aft
      2 raised mounts
      8 - 0.59" / 15.0 mm 90.0 cal guns - 0.11lbs / 0.05kg shells, 4,000 per gun
     Machine guns in deck mounts, 1931 Model
     4 x Twin mounts on sides, evenly spread
      4 raised mounts
      Weight of broadside 288 lbs / 131 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.18" / 30 mm   0.79" / 20 mm      1.18" / 30 mm
   2nd:   0.59" / 15 mm         -               -
   3rd:   0.59" / 15 mm         -               -

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 49,262 shp / 36,750 Kw = 33.29 kts
   Range 13,400nm at 10.00 kts
   Bunker at max displacement = 567 tons

Complement:
   181 - 236

Cost:
   £1.244 million / $4.975 million

Distribution of weights at normal displacement:
   Armament: 83 tons, 3.2%
      - Guns: 83 tons, 3.2%
   Armour: 28 tons, 1.1%
      - Armament: 28 tons, 1.1%
   Machinery: 1,300 tons, 50.0%
   Hull, fittings & equipment: 607 tons, 23.3%
   Fuel, ammunition & stores: 443 tons, 17.0%
   Miscellaneous weights: 142 tons, 5.5%
      - Hull below water: 25 tons
      - On freeboard deck: 57 tons
      - Above deck: 60 tons

Fittings:
-9 t:  Fire control (AD)
-25 t:  L/R wireless (AD)
-10 t:  Nightfighting doodads (AD)
-10 t:  Huelsmeyer device (AD)
-32 t:  2x4 21" TT (FD)
-15 t:  ASW munitions (FD)
-10 t:  Sonar (BW)
-15 t:  Enhanced hydrophone package (BW)
-10 t + 6 t:  Weight reserve (FD/AD)

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     602 lbs / 273 Kg = 9.0 x 5.1 " / 130 mm shells or 0.3 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 1.4 ft / 0.4 m
   Roll period: 13.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.45
   Seaboat quality  (Average = 1.00): 1.00

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.410 / 0.423
   Length to Beam Ratio: 10.53 : 1
   'Natural speed' for length: 19.84 kts
   Power going to wave formation at top speed: 64 %
   Trim (Max stability = 0, Max steadiness = 100): 70
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 3.94 ft / 1.20 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00%,  23.95 ft / 7.30 m,  19.03 ft / 5.80 m
      - Forward deck:   25.00%,  19.03 ft / 5.80 m,  19.03 ft / 5.80 m
      - Aft deck:   40.00%,  11.15 ft / 3.40 m,  11.15 ft / 3.40 m
      - Quarter deck:   15.00%,  11.15 ft / 3.40 m,  11.15 ft / 3.40 m
      - Average freeboard:      15.09 ft / 4.60 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 174.2%
      - Above water (accommodation/working, high = better): 136.1%
   Waterplane Area: 9,119 Square feet or 847 Square metres
   Displacement factor (Displacement / loading): 77%
   Structure weight / hull surface area: 37 lbs/sq ft or 181 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 1.38
      - Overall: 0.55
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform

[The Rock Doctor]

Pondering life-extension options for the Angstrom class battleships.  Laid down between 1913 and 1915, they would ideally be leaving service after 25 years in about 1940-1942.  So they're just at, or approaching, the middle of their careers.

The class is not bad; speed is good, belt and torpedo protection are adequate.  Deck armor is falling behind modern artillery/bomb trends.  The big problem is the armament, because I designed them at a time when I did not remember the difference between a triple turret and a 3-gun turret and went for the former.  This problem was repeated in the following two classes of battlecruiser, too.

The class had a refit a few years back and picked up new AA and torpedo nets, and of course, they'll be in for fire control updates in the future.

Refurbishment options include FC and new 2-gun 100mm DP mountings, which are not hugely consequential to what follows.  Major decisions are needed for the following options:

Engine Room

1)  A basic replacement of the engines would increase hull strength enough that I could add another 30mm (on top of existing 90) of deck armor to the main and quarter decks.  That'd be about 3 BP, roughly speaking.

2)  Alternately, I could increase power to 27 knots, which only allows for the main deck to receive a 20mm topping.  This lets the class keep pace with the Encke and Gadolin classes; seakeeping remains reasonable.  I assume the BP cost would be about equal.

Main Battery

1)  Nothing; retain the 350/45 in a single sleeve in triple turrets and get ~1.5 rounds a minute.  No cost.

2)  Replace with a new model 350/45, shooting the same sized shells and using the same triple turrets and their protection.  Not sure how the newer gun tech would affect ROF or penetration.  Cost is in the range of 2.1 BP

3)  Replace with a new model ~320-325mm gun, shooting smaller but relatively super-heavy shells from a 3-gun turret.  Likely ROF increase but possible modest drop in firepower.  Will need to replace turret armor but not barbette armor.  Magazine weight would be kept unchanged.  Cost bumps to around 2.9 BP

4)  Replace with a new model ~370-380mm gun, shooting heavier projectiles from a 2-gun turret.  Better penetration, but down to 6 barrels overall.  New turret but same barbette.  Unknown ROF, might not be much improved.  Figure cost remains about 2.9 BP.

Additional thoughts

Any re-gunning option delays the refurbishments to at least 1932 because as of 1929 I haven't designed any of the replacement gun options.  At that point, Anders Angstrom is in the yard for the better part of 1932 and has a theoretical ~eight years of service afterward.  Her sisters follow the same schedule at one year intervals.

For context, it is likely that the class would become the core of the Caribbean Fleet for most of their remaining service lives, so that gives a sense of who the potential OPFORs could be.

Thoughts?

[Jefgte]

...2)  Alternately, I could increase power to 27 knots, which only allows for the main deck to receive a 20mm topping.  This lets the class keep pace with the Encke and Gadolin classes; seakeeping remains reasonable.  I assume the BP cost would be about equal...

Good rebuilt
=>This lets the class keep pace with the Encke and Gadolin classes.

[Kaiser Kirk]

The increase of speed would have two results
A)  In cases your 27knot ships need to sprint for a couple hours..which is likely rare...they could keep up.
B)  It might mean, if you have a 2-3 knot advantage over an opposing battlewagon you could choose to engage or disengage...though their speed when encountered vs. your speed would effect that, as would if there was a locational tie - attacking/defending a convoy/harbor/beach head.

C) Cost, Engine tonnage costs 2x $ compared to armor tonnage. Trivial at the tonnage at issue.

D) Gun sizing- obviously I've been going with more recent gun tech new guns.
The gun chart in Gun Research unfortunately no longer seems to have the ME to MV conversion formula, but I have it
in spreadsheets I use to evaluate potential guns.

For example, I rearmed the Asbara ACs from 255/50 to 255/47 with bigger, faster shells, while the new 333L43 has a bigger shell and more penetration than my old 345L40 - which with the rebuilding of the Gilgamesh/Enki is out of service. 
Likewise I know my 365L50 is actually quite similar in performance to the 390L46, and my 435L43 isn't world beating.

D1) Step 1 of Penetration is handled by taking the MV resulting from plugging in the player's tech level when the gun came out...as best determined...and the shell weight ...to get the MV.

D1.1 ) Shell Weight: Usually I figure the max shell weight for bore/caliber/overwieght Tech you have is the max you can use for that bore.

D1.2 ) ME : For 12"+, ME is fixed for the tech tree.  Shorter calibers get a pro-rated ME. So a 52 on a 55 max would be 52/55 *ME.

D1.3 ) ME : For 10" less, things don't scale well, and so I use a % of max bore area as well.

D2)  Step 2 of penetration depends on the players current gun tech, governing AP shell performance. I try to find a similar era shell with penetration listed in Nav Weaps, and plug different numbers into Logi's Ballistics Calc to get a 'standard' value for that type.

D3) Step 3 of penetration is taking the MV and Shell weight, putting them into Logi's or BigGun, putting in the derived AP value and then seeing what it can do.

D4) The intent was at some point to create a table of sample guns and expected MV, and possibly even sample penetrations to help inform the player base.

E1) ROF... currently I look at Navweaps for about that boresize and year and get a base ROF. I then consider the Two-gun vs Triple, etc. adjustments in the Ship Design thread.

E2 ) I have started a master ROF effort which sought to take all the Navweaps period guns, adjust for mounting type, break them into gun tech periods and then derive a linear regression formula which would simplify such things. Started...never finished.

F) Yes, all this adds substantially to "prep" for wars. Especially as guns proliferate, so one fleet may have alot. At least the Armor pen is tech related, so those numbers are the same for

G) These are the types of things I work on when not doing other things and I'm actually caught up on other moderator things AND the Parthian fleet, which explains why they are not finished and posted where they are useful.  I keep meaning to make a master list of 'Mod Clarifications', but as you all know, I struggle to find the time & energy to keep up as it is.

H)  IF there is a desire to find out the Penetration for a desired Gun, I can run it for folks. Probably use the 1920 tech AP numbers though, as I think I wrote that down on my excel sheet.

[The Rock Doctor]

What do you reckon the ROF difference is between a triple turret and a 3-gun turret?

[TacCovert4]

What do you reckon the ROF difference is between a triple turret and a 3-gun turret?

If everything is working perfectly and you're firing broadside....nothing.  if you're firing partial salves the individual sleeves allow you to load on a split.  If you have a gun go down it keeps the whole turret from potentially going down.

I tend to do twins where the mount will always be operating as a single unit, like a secondary mount.  And 2 gun when it's a main mount

[Kaiser Kirk]

In practice, they seem to have found the smaller gun housing, as well as delays due to drill errors on one gun effecting the entire slide, caused a delay on single-slides.
This is without considering shell interference issue and it's effect on accuracy. But we're not worried about delay coils here.

What is under the ship design thread is :

Multiple guns
Generally speaking, historical twin mounts had a higher rate of fire (ROF) than the historical triple mounts. Also, ROF on Single-sleeve triple mounts were slower than 3-gun triple mounts. The reason is apparently the loading cycle. Actual rates of fire would vary by bore, nation and date of design. There are even cases where more practice and procedural changes increase a guns ROF.  Some of those changes could simply be to throw safety precautions away.

The use of a single slide gives ~90% of the ROF of a "x-gun" design.
Adding a 2nd or 3rd barrel each applies ~90% reductions.

A "Quad" is a single slide,
while "Pair of Twins" is a "4-gun" and treated as 2 Twins for ROF.
A "True Quad" is also a "4-gun" and treated as 2 Two Guns for ROF.

Example : A 2-Gun 14" Turret - ROF 2 / barrel
A single 14 would then be 2 (base ROF) / 0.9 (only 1 barrel) = 2.22 ROF
A Triple 14" Turret then would have = 2 (base ROF) * 0.9 (+1 barrel)  * 0.9 *single slide) = 1.62 ROF / Barrel

The "Quad" effect is unknown, but it the "pair of twins" quad apparently avoids a reduction by having two ammo feeds, turning the turret into a 'pair of twins' with that ROF.

Edit : I presume I was basing it on the Navweaps for USS Pennsylvania
Rate Of Fire   New York class - about 1.25 - 1.5 rounds / minute
Nevada and Pennsylvania classes - about 1.5 - 1.75 rounds / minute

[The Rock Doctor]

Mmm.  So developing a new gun and a 3-gun turret for it is a fair bit of effort to offset, basically, a loss of 10% of rate of fire.

[Kaiser Kirk]

Yes, though the new gun would more than likely be more effective than the old gun.
The opportunity cost is a couple years and $1.00 in research funds.

[The Rock Doctor]

Indeed.

[Kaiser Kirk]

I see above you were thinking of a 6-gun version, so this element from the Ship Design thread is pertinent.
As we get into Aerial spotting, perhaps a bit less so, but in a contested aerial environment, limited visibility, or large engagement with many shell splashes from many ships,
it may be difficult to use.


Fire Control
For splash spotting, salvos of 4+ guns are desirable.

Early on, they wanted 10 guns, so 5 would fire in a salvo, and if 1 had a loading delay there would be 4 guns.  Later, they decided the delays were not common, and they could use 8 guns for the 4 shell salvo.

Lesser patterns can work, but with less effectiveness