Aztec Ships 1915-1917

[TacCovert4]

After the thwarting of an MTB-A attack on Galveston Bay due to Roman Sloops, the Sultanate is looking at acquiring vessels of this type.  Currently, 20 Minesweeper/Patrol craft are in existence, but the MS-1 class has three primary concerns, those being lack of FC, only a single gun, and they're slow.  These three concerns were all apparent in the Galveston Bay operation as the similar Roman Sloops slow speed, lack of FC, and paucity of firepower meant that they were practically irrelevant to the operation outside of initially spotting.  They could not get into place to block either ingress or egress, and couldn't appreciably contribute to the gunfire. 

The Sultanate also has a secondary concern due to the war.  The original plan was to use the Toucan-class cruisers, modernized in 1916, as 'station cruisers' at the various colonies.  The Sultanate has colonies spread fairly broadly worldwide, with a 'near colony' at the Windwards (and Caicos at the moment, we shall see how that progresses in December-1914), and 'far colonies' at Angola, Zealand, and Wake.  Any station ships would have to have sufficient endurance to provide patrol duties in those areas, and would have to be sufficiently powerful to create a deterrent against raiding vessels or local unrest.

This initial design (possibly for late 1915 production, could be 1916 though) brings in minesweeping and limited Marine capabilities combined with a 'best in class' armament of 2 twin 100mm guns and a suite of machine guns for anti-aircraft or anti-boat use.  Splinter protection sufficient to protect against fire from many MTBs and up to 100mm HE splinters is also included for the bridge and main guns.  Unlike previous patrol vessels, these would have a relatively high top speed that would allow them to evade cruisers or pursue torpedo craft.

Sloop X, Aztec Sloop laid down 1915

Displacement:
   499 t light; 526 t standard; 591 t normal; 642 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (294.90 ft / 291.99 ft) x 26.25 ft x (6.56 / 6.94 ft)
   (89.88 m / 89.00 m) x 8.00 m  x (2.00 / 2.12 m)

Armament:
      4 - 3.94" / 100 mm 50.0 cal guns - 32.30lbs / 14.65kg shells, 200 per gun
     Quick firing guns in deck mounts, 1915 Model
     2 x Twin mounts on centreline ends, evenly spread
      8 - 0.31" / 8.0 mm 70.0 cal guns - 0.02lbs / 0.01kg shells, 2,000 per gun
     Machine guns in deck mounts, 1915 Model
     4 x Twin mounts on sides, evenly spread
      Weight of broadside 129 lbs / 59 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.79" / 20 mm         -               -

   - Conning towers: Forward 0.79" / 20 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 14,475 shp / 10,799 Kw = 30.00 kts
   Range 5,000nm at 10.00 kts
   Bunker at max displacement = 117 tons

Complement:
   59 - 77

Cost:
   £0.096 million / $0.385 million

Distribution of weights at normal displacement:
   Armament: 22 tons, 3.7 %
      - Guns: 22 tons, 3.7 %
   Armour: 5 tons, 0.8 %
      - Armament: 4 tons, 0.6 %
      - Conning Tower: 1 tons, 0.2 %
   Machinery: 296 tons, 50.2 %
   Hull, fittings & equipment: 158 tons, 26.7 %
   Fuel, ammunition & stores: 91 tons, 15.4 %
   Miscellaneous weights: 18 tons, 3.1 %
      - Hull above water: 3 tons
      - On freeboard deck: 12 tons
      - Above deck: 3 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     162 lbs / 74 Kg = 5.3 x 3.9 " / 100 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.11
   Metacentric height 0.8 ft / 0.2 m
   Roll period: 12.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 65 %
         - Recoil effect (Restricted arc if above 1.00): 0.25
   Seaboat quality  (Average = 1.00): 0.72

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.411 / 0.422
   Length to Beam Ratio: 11.13 : 1
   'Natural speed' for length: 17.09 kts
   Power going to wave formation at top speed: 64 %
   Trim (Max stability = 0, Max steadiness = 100): 91
   Bow angle (Positive = bow angles forward): 15.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  10.83 ft / 3.30 m,  10.17 ft / 3.10 m
      - Forward deck:   30.00 %,  10.17 ft / 3.10 m,  9.19 ft / 2.80 m
      - Aft deck:   35.00 %,  9.19 ft / 2.80 m,  8.20 ft / 2.50 m
      - Quarter deck:   15.00 %,  8.20 ft / 2.50 m,  8.20 ft / 2.50 m
      - Average freeboard:      9.26 ft / 2.82 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 175.3 %
      - Above water (accommodation/working, high = better): 140.3 %
   Waterplane Area: 4,749 Square feet or 441 Square metres
   Displacement factor (Displacement / loading): 50 %
   Structure weight / hull surface area: 23 lbs/sq ft or 111 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 0.77
      - Overall: 0.52
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

2.4t - 1908 FC
1t - Additional Searchlights
8t - Minesweeping Gear
4t - 2t patrol launch
3t - Space for up to 12 Marines for colonial patrol duties

[TacCovert4]

Considerations being looked at in the "B-Build" are to remove minesweeping gear, leaving that duty to the slower MS-1 class of which there are sufficient numbers to put one or two on colonial stations with the sloops, in favor of either a single twin or triple torpedo launcher or improved splinter protection to 24mm.  The former would give some threat against larger ships, though MTB-Bs are planned to be stationed in colonial areas for duties there, the latter would protect against 140mm HE splinters, the largest fired by anticipated destroyer-level threats.  A third option for removing minesweeping gear would be to raise the freeboard further....as it stands she has 'destroyer grade' performance at speed in a seaway, though one would expect that her seakeeping performance at a more normal 'patrolling speed' would be more than sufficient for inshore and limited offshore work.

[Kaiser Kirk]

We had a big discussion on mounts and requisite width back in the spring and the players decided that if SS doesn't trigger a warning, it's ok.   
I was in the 'I think there should be rules' camp, we (or maybe just I) didn't win.

That said, a twin 100mm on an 8m beam with a .411 BC seems unreasonable, but hey SS doesn't give a warning.

Oil firing : If this is a station ship, and you find yourself in a similar situation to the Caicos, which of your colonies produced oil in the early 1900s ?  You can ship it from home, you can buy it abroad, but I don't believe any of those places produce it themselves.   For my part, Parthia is a huge oil producer, but I've continued building my vessels with partial coal firing in some cases, so they can be deployed to colonies and use that to day to day operations without oil stocks being a concern.

FC - I don't care for fractional tons.  Feel free to round 0.1 - 0.4 down.

8t Minesweeping gear... this gets back into the 'what am I supposed to do with this'.  Extrapolating from how I treated Snip's , basically you get some paravanes with floats, but they aren't very robust and will only clear a limited number of moored mines. Which may fit the need.

1t searchlight... basic searchlights are part of ships fittings. This means you have a bonus one.... ?

2t ship's launch... typical ships boats are part of the ships fittings, so this "buys" a bonus 1 ton launch. "Boats:  Typical ship's boats are part of fittings.  Extra boats, landing craft, or attack craft require 2 t of miscellaneous weight per tonne of boat weight"  ...which per troops below would hold 4 guys ?

3t for 12 Marines.   From Ship design guidelines, Troops:  1 t per four troops for short-ranged landing craft.  2 t per troop for long-term (> 1 day) embarkment., so what this buys is <24hrs on board.

[The Rock Doctor]

I just round the FC cost up to the next whole number.  If nothing else, it gives a bit of slack if I add some light guns later.

[TacCovert4]

BBy, Aztec Battleship laid down 1916

Displacement:
   24,582 t light; 25,970 t standard; 27,617 t normal; 28,934 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (656.03 ft / 652.56 ft) x 91.21 ft x (24.61 / 25.61 ft)
   (199.96 m / 198.90 m) x 27.80 m  x (7.50 / 7.81 m)

Armament:
      9 - 14.17" / 360 mm 45.0 cal guns - 1,435.69lbs / 651.22kg shells, 100 per gun
     Breech loading guns in turret on barbette mounts, 1916 Model
     3 x 3-gun mounts on centreline, forward evenly spread
      1 raised mount
      14 - 5.12" / 130 mm 50.0 cal guns - 70.97lbs / 32.19kg shells, 200 per gun
     Quick firing guns in deck and hoist mounts, 1916 Model
     6 x Twin mounts on sides, aft evenly spread
     1 x Twin mount on centreline, aft deck aft
      1 raised mount
      4 - 2.76" / 70.0 mm 50.0 cal guns - 11.09lbs / 5.03kg shells, 300 per gun
     Anti-air guns in deck mounts, 1916 Model
     4 x Single mounts on centreline, aft evenly spread
      4 raised mounts
      16 - 0.31" / 8.0 mm 70.0 cal guns - 0.02lbs / 0.01kg shells, 2,000 per gun
     Machine guns in deck mounts, 1916 Model
     8 x Twin mounts on sides, evenly spread
      Weight of broadside 13,959 lbs / 6,332 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   12.6" / 320 mm   426.51 ft / 130.00 m   16.40 ft / 5.00 m
   Ends:   1.97" / 50 mm     95.14 ft / 29.00 m   16.40 ft / 5.00 m
     130.91 ft / 39.90 m Unarmoured ends
     Main Belt covers 101 % of normal length

   - Torpedo Bulkhead - Additional damage containing bulkheads:
      1.57" / 40 mm   393.70 ft / 120.00 m   22.97 ft / 7.00 m
   Beam between torpedo bulkheads 72.18 ft / 22.00 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   12.6" / 320 mm   4.72" / 120 mm      12.6" / 320 mm
   2nd:   4.33" / 110 mm   1.97" / 50 mm      3.94" / 100 mm

   - Armoured deck - multiple decks:
   For and Aft decks: 3.54" / 90 mm
   Forecastle: 0.00" / 0 mm  Quarter deck: 2.95" / 75 mm

   - Conning towers: Forward 4.33" / 110 mm, Aft 4.33" / 110 mm

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 2 shafts, 54,841 shp / 40,911 Kw = 24.00 kts
   Range 6,000nm at 14.00 kts
   Bunker at max displacement = 2,964 tons

Complement:
   1,070 - 1,392

Cost:
   £4.024 million / $16.097 million

Distribution of weights at normal displacement:
   Armament: 2,924 tons, 10.6 %
      - Guns: 2,924 tons, 10.6 %
   Armour: 9,310 tons, 33.7 %
      - Belts: 3,923 tons, 14.2 %
      - Torpedo bulkhead: 527 tons, 1.9 %
      - Armament: 1,969 tons, 7.1 %
      - Armour Deck: 2,721 tons, 9.9 %
      - Conning Towers: 170 tons, 0.6 %
   Machinery: 2,043 tons, 7.4 %
   Hull, fittings & equipment: 9,397 tons, 34.0 %
   Fuel, ammunition & stores: 3,035 tons, 11.0 %
   Miscellaneous weights: 908 tons, 3.3 %
      - Hull below water: 515 tons
      - Hull above water: 193 tons
      - Above deck: 200 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     36,540 lbs / 16,574 Kg = 25.7 x 14.2 " / 360 mm shells or 5.9 torpedoes
   Stability (Unstable if below 1.00): 1.15
   Metacentric height 5.7 ft / 1.7 m
   Roll period: 16.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0.65
   Seaboat quality  (Average = 1.00): 1.08

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.660 / 0.664
   Length to Beam Ratio: 7.15 : 1
   'Natural speed' for length: 25.55 kts
   Power going to wave formation at top speed: 47 %
   Trim (Max stability = 0, Max steadiness = 100): 56
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  19.69 ft / 6.00 m,  18.04 ft / 5.50 m
      - Forward deck:   30.00 %,  18.04 ft / 5.50 m,  14.76 ft / 4.50 m
      - Aft deck:   35.00 %,  14.76 ft / 4.50 m,  14.76 ft / 4.50 m
      - Quarter deck:   15.00 %,  14.76 ft / 4.50 m,  14.76 ft / 4.50 m
      - Average freeboard:      16.04 ft / 4.89 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 88.7 %
      - Above water (accommodation/working, high = better): 127.1 %
   Waterplane Area: 46,013 Square feet or 4,275 Square metres
   Displacement factor (Displacement / loading): 103 %
   Structure weight / hull surface area: 180 lbs/sq ft or 881 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.99
      - Longitudinal: 1.05
      - Overall: 1.00
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room

515t - Electric Drives

293t - 1912 FC
25t - LR Radio
50t - Flag Accommodations
25t - Night Acquisition Devices (1908)

Decks:
Main - 75mm + 15mm Splinter
Quarter - 60mm + 15mm Splinter

Belts:  End Belt is Aft of Main Belt covering steering gear, shafts, etc.  Foc'stle is true AoN and is outside of raft body

[TacCovert4]

Haven't settled on a class name yet, or even how many will be built.  The Sultanate finds itself with such a dearth of capital units in the aftermath of the war that the Implacables sitting in the fitting out basin of Veracruz are the only battleships in the fleet, not scheduled to be commissioned until January of 1916. 

Designs for ships from a 27kt Fast Battleship (had been put forward before) to a selection of 21 and 24kt battleships with 12 x 360mm guns were considered.  There was even significant talk of eschewing battleships entirely for an all-cruiser navy with Battlecruisers as the capital ship. However, despite the decisive rout at Ironclad Bay, the ultimate lessons gleaned from it were that a lack of suitable fire control, coupled with inadequate guns both in numbers and firepower, and inadequate armor was responsible.  So any new vessel would need heavy armor able to withstand a significant pounding, along with more substantial flotation to allow the ship to remain combat capable even after suffering penetrations to the armor.  The 12 gun designs were discarded as too large and complex to allow for continued production of cruisers and light units to replace losses suffered during the war.  280mm designs were also discarded out of hand as insufficient in firepower to match against the 340mm guns Roman units were bringing to bear, this is also considered to be the main and most glaring weakness of the Implacable design. 

Ultimately a 9 gun 360mm battleship with a 24kt speed allowing it to match the Implacables for battle line management was decided upon. The unusual all-forward arrangement of the armament was considered to help in a pursuit as it allows all three turrets to fire at more extreme angles.  Main Belt armor and Deck armor were maximized, and the fire control center moved from the conning tower to under the main armor deck.  Range was acceptable even if low by standards.

Protection for the areas outside the citadel was carefully considered.  As the class was primarily designed for Caribbean operations and not for high speed runs on the open ocean, the forecastle area was left completely unarmored.  This was felt to be sufficient to allow heavy AP shells to overpenetrate without detonating inside the ship, while the holes punched would not be letting water into the main 'raft body' of the ship.  Aft, the threat to the drives and steering gear by splinters and smaller shells from destroyers and light cruisers drove an end belt and light deck. 

With the relatively low speed compared to length, power requirements were relatively minimal, even with the added tonnage of turbo-electric drives.  Only two shafts are to be fitted, as the redundancy is not felt to be a necessity in waters closer to home, and the removal of outboard shaft runs adds to the durability of the ship itself and it's TDS, and minimizes the possibility of a low shell or torpedo hit from causing a catastrophic shaft warpage. 

The other unique change to the ship design is the cutting of armor protection for the bridge to merely splinter and light shell protection.  The conning towers were not hit during the battle, and the captains and senior officers preferred to work in the unarmored bridge sections rather than in the confines of the conning tower anyway.  With that in mind, two armored bridge sections and a communications trunk were designed in, each individually unable to take a heavy shell hit, but the redundancy able to ensure continued operations even after being hit.

[The Rock Doctor]

I guess there's no time like complete annihilation to reset one's fleet ideas.

They're economic, no doubt, decent turn of speed and armament.  I wonder if the conning tower might still be a bit too heavily armored to avoid setting off heavy calibre hits.

[snip]

I like it, nasty little customer. My one thought is that moving to twin M&H is a bit of a big leap, and would only allow for simultanious tracking a smaller number of targets over single mounts. Since so far we have mostly be dealing with saturation attacks when it comes to torpedo craft, I wonder if keeping singles would be better for that reason.

[TacCovert4]

I like it, nasty little customer. My one thought is that moving to twin M&H is a bit of a big leap, and would only allow for simultanious tracking a smaller number of targets over single mounts. Since so far we have mostly be dealing with saturation attacks when it comes to torpedo craft, I wonder if keeping singles would be better for that reason.

Good point.  My logic is threefold.   1)  twin mount and hoist is already in the pipe.  It would tax the research budget to add yet another mount.   2)  it's less likely with a battleship in a fleet to get a full saturation attack without being supported.   3)  a single gun firing on a single target is horrible for FC.  4 guns is the standard for FC.  If the secondary is at the point of independent fire,  having 14 guns firing at 14 targets or 14 guns firing at 7 targets is probably going to go to the 7 targets being more efficiently serviced.  Overall I think that 7 mounts with significant protection for their gunners to calmly engage destroyers and torpedo boats is superior to 14 smaller mounts firing at half the rate.

[snip]

You do get a free single deck mount (with or without a hoist) will all guns 209mm or lower, so no need to research anything there. The rest makes sense.

[Jefgte]

- Conning towers: Forward 4.33" / 110 mm, Aft 4.33" / 110 mm

One hit could destroy the ship's command.
IMO, update to 320mm

[TacCovert4]

- Conning towers: Forward 4.33" / 110 mm, Aft 4.33" / 110 mm

One hit could destroy the ship's command.
IMO, update to 320mm

That's the point of having two of them.  Plus the conning tower has always been a death trap even when it's thick.  If it gets hit there's going to be carnage.   Better off having it splinter protected and redundant than putting everything into one spot in my opinion.

[snip]

I seem to recall that there is a bug with the aft conning tower item where Springsharp does not count its weight.

[Desertfox]

Time to put 20" armor on that aft tower!  ;D

[TacCovert4]

I seem to recall that there is a bug with the aft conning tower item where Springsharp does not count its weight.

I'll test and verify.   But as I recall it did count the weight.