Iberian Navy

[Logi]

Post start-up the unprotected cruiser gets a slight update in that it gets tonnage dropped by 300 tons in excahnge for 12 rounds on the battery.

Hull-016, Iberia Unprotected Cruiser laid down 1900

Displacement:
   1,200 t light; 1,265 t standard; 1,440 t normal; 1,580 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (272.50 ft / 272.50 ft) x 26.00 ft x (14.00 / 15.03 ft)
   (83.06 m / 83.06 m) x 7.92 m  x (4.27 / 4.58 m)

Armament:
      7 - 6.00" / 152 mm 40.0 cal guns - 103.51lbs / 46.95kg shells, 89 per gun
     Breech loading guns in deck mounts, 1900 Model
     3 x Single mounts on centreline, evenly spread
     4 x Single mounts on sides, evenly spread
      Weight of broadside 725 lbs / 329 kg
      Main Torpedoes
      8 - 17.7" / 450 mm, 16.40 ft / 5.00 m torpedoes - 0.504 t each, 4.028 t total
   In 4 sets of deck mounted side rotating tubes

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 6,430 ihp / 4,796 Kw = 21.00 kts
   Range 4,000nm at 10.00 kts
   Bunker at max displacement = 315 tons (100% coal)

Complement:
   116 - 151

Cost:
   £0.173 million / $0.692 million

Distribution of weights at normal displacement:
   Armament: 104 tons, 7.2 %
      - Guns: 96 tons, 6.7 %
      - Weapons: 8 tons, 0.6 %
   Machinery: 719 tons, 49.9 %
   Hull, fittings & equipment: 373 tons, 25.9 %
   Fuel, ammunition & stores: 240 tons, 16.7 %
   Miscellaneous weights: 4 tons, 0.3 %
      - Above deck: 4 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     474 lbs / 215 Kg = 4.4 x 6.0 " / 152 mm shells or 0.6 torpedoes
   Stability (Unstable if below 1.00): 1.38
   Metacentric height 1.2 ft / 0.4 m
   Roll period: 10.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 0.86
   Seaboat quality  (Average = 1.00): 1.20

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.508 / 0.519
   Length to Beam Ratio: 10.48 : 1
   'Natural speed' for length: 16.51 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 58
   Bow angle (Positive = bow angles forward): 0.00 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 %,  10.00 ft / 3.05 m,  9.00 ft / 2.74 m
      - Forward deck:   30.00 %,  9.00 ft / 2.74 m,  9.00 ft / 2.74 m
      - Aft deck:   35.00 %,  9.00 ft / 2.74 m,  9.00 ft / 2.74 m
      - Quarter deck:   15.00 %,  9.00 ft / 2.74 m,  9.00 ft / 2.74 m
      - Average freeboard:      9.08 ft / 2.77 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 181.3 %
      - Above water (accommodation/working, high = better): 66.6 %
   Waterplane Area: 4,756 Square feet or 442 Square metres
   Displacement factor (Displacement / loading): 63 %
   Structure weight / hull surface area: 48 lbs/sq ft or 236 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.93
      - Longitudinal: 1.90
      - Overall: 1.00
   Cramped machinery, storage, compartmentation space
   Cramped accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

[Jefgte]

IMO,
1200t with 7x152...
The hull is overloaded & stressed
Recoil is too high: 0.86

Jef  ;)

[KWorld]

It's a slower, smaller GTB-1916: great against merchants and AMCs, in real trouble against cruisers because it can't reject any hits and it can't take them either.  3" or larger shells will cause it real problems, and it's actually fairly vulnerable to TBDs shooting it up because it doesn't have any quick-firing guns to engage with.  Doesn't help that there are big lockers on deck full of 6" shells and powder charges.

[Logi]

IMO,
1200t with 7x152...
The hull is overloaded & stressed
Recoil is too high: 0.86

Jef  ;)

I noticed - I'm seriously questioning the merit of designing a ship for 1900 period until ~1908. The improvements are so incremental that it's pointless to make a new design. For example, I was barely about to squeeze out the 300 ton save in a 4 year time gap by over-stressing the hull.

It's a slower, smaller GTB-1916: great against merchants and AMCs, in real trouble against cruisers because it can't reject any hits and it can't take them either.  3" or larger shells will cause it real problems, and it's actually fairly vulnerable to TBDs shooting it up because it doesn't have any quick-firing guns to engage with.

You are seriously comparing the speed of a 1900 ship and a 1916 ship? (Not to mention almost all contemporary cruisers are 21-22 kts) Also practically all cruisers have trouble vs other cruisers in this time period. The guns, assuming a shell that doesn't shatter on contact, can all penetrate each other's armor with no problem. So why put armor on a ship that is 1,200 tons. You know that is just over double the size of a destroyer and well under 1/4 or 1/3 the size of your contemporary cruisers in the USN.

Your cruisers also don't even have the armor to shatter the shells on contact - let alone reject the shells.

Another note, 4" guns of 1900 have a fire rate of 7~8 rounds per minute, 6" guns of 1900 had a fire rate of 5-7 rounds per minute. 3" guns have a fire rate of ~15 rounds per minute. The guns don't fire THAT slow that it is so vulnerable to TBs.

It has 7 6" guns to fire a broadside, has torpedoes, and has a decent speed (DDs of the period are hard pressed dot manage more than 27 kts trial speed - unless ofc it's just little more than a PT boat in which case 1 hit sinks them). If you really want to try it, I can do what CT did once before - calculate the approximate number of such ships you would need to torpedo or gun down this cruiser. His numbers revealed a disproportional advantage to the larger ship and concluded that a TB/DD attack would only be feasibly efficient on tonnage in very very rare cases.

Remember speed of a ship negatively affects gun accuracy and larger caliber guns typically have larger engagement radii. In short, how many TBs are you sending after a 1,200 ton ship to guarantee the kill? Assuming DDs of 500, anything over 2 means you've wasted more tonnage sinking the ship than target weighted. Assuming TBs of 200, anything over 6 applies similarly.

Doesn't help that there are big lockers on deck full of 6" shells and powder charges.

When your ship is practically a destroyer, I don't think it is much of a concern.

[KWorld]

The reason to put armor on cruisers is to prevent shell fragments from holing water-tight compartments that were not hit.  That's the idea behind a protected cruiser: the sloped "belt" (actually the downward sloping deck edges) protects against direct penetration, and the deck armor protects against fragments that would allow water into the protected compartments beneath the deck (which are intended to keep the ship afloat).  In this ship, fragments from a shell exploding above the waterline can cause flooding in multiple compartments by penetrating the hull below the waterline.


You have 5 guns per broadside, the other 2 are on the other side.  5-7 rpm for period best case, a little boat like this isn't the best case.  It's a good seaboat for a 1200 ton vessel, but that doesn't mean it doesn't react to the seas more than a larger vessel, seaboat rating is size-relative.  Keep in mind the problems the much larger WWII German DDs with 15cm guns had serving them, while your ship is slower it's also less than half their size.


It's about 1/3 the size of my USN cruisers: most of those are ~3400 tons light, I don't have any that are ~4800 tons light (looked at a design, once, but it didn't work out so it was never finished).  This ship has 2 more 6" guns, 1 of which will bear on a broadside, the USN ships have 6 extra 4" guns and 8 extra 6-pounders.

[Jefgte]

IMO,
Instal on a 1200-1400t hull-21kts,  4 x 6" Single mounts on centreline, a couple of QF guns & a 1" Belt-Deck armor.

Jef

[Tanthalas]

France and Italy had a history of building ships like these, however atleast the Italians used a more intermediate gun (4.7" QFs) the Italian ships were unarmored but actualy dont work as built in Spring Sharp (with our rules restrictions atleast).  I ended up at 1200 tons to get them to work at a 1.00 composite (however mine also hit 22 knots)

[Logi]

That's the idea behind a protected cruiser: the sloped "belt" (actually the downward sloping deck edges) protects against direct penetration

The point is unless you have 3" or more of deck at slope (2.12" flat deck according to historical US ships) the armor isn't even going to shatter poor 6" projectiles, let alone protect against direct penetration of non-subpar ammunition.

This means very few cruisers can protect against 6" rounds unless they are much larger ships (I've only seen 10K+ ton cruisers simmed with that kind of armor).

5-7 rpm for period best case, a little boat like this isn't the best case.

Um no? 5-7 rpm was what 6" guns did. Best case was 8 rpm. Also gunnery best case has very little to do with boat size - it has to do with boat stability, heel, and roll. While those are related to ship size (natural benefit through ship size) it doesn't mean a small ship is automatically bad at it.

Case in point, the ship has a roll period of 10.1 seconds - your Pennsylvania class of 11.5K ton has a roll period of 12.3 seconds. A difference of 2 seconds while the larer ship has 10" guns.

It's a good seaboat for a 1200 ton vessel, but that doesn't mean it doesn't react to the seas more than a larger vessel, seaboat rating is size-relative.  Keep in mind the problems the much larger WWII German DDs with 15cm guns had serving them, while your ship is slower it's also less than half their size.

Size is not the main determinate of the seakeeping. You need to keep in mind that the WW2 German DDs were much faster, which produces a substantially larger bow wave height. Not to mention the problems of seakeeping they had was fixed through a better bow design. As for the problem with the gun and wetness - that was primarily due to the lower buoyancy at forecastle due to a poor distribution of guns along the ship. This wasn't helped by the fact that the fore gun was a twin semi-turret.

As for seakeeping - The bow wave height of this ship at 21 kts is only 2.59 ft.
In a sea of 5 ft waves in H[1/3] state- the minimum bow height required for 10% wetness is 7.39 ft.
In a sea of 10 ft waves in H[1/3] state - the minimum bow height required for 10% wetness is 9.38 ft.

Meaning - The ship will survive in 10 ft and below waves. The ship doesn't even have to worry about exposed belt since it doesn't have armor to begin with.

[Logi]

Modified according to Jefgte's suggestions:
Splinter armor added - a few QF guns added.
+100 tons

Hull-016, Iberia Protected Cruiser laid down 1900

Displacement:
   1,300 t light; 1,360 t standard; 1,545 t normal; 1,693 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (300.00 ft / 300.00 ft) x 26.00 ft x (14.00 / 15.00 ft)
   (91.44 m / 91.44 m) x 7.92 m  x (4.27 / 4.57 m)

Armament:
      4 - 6.00" / 152 mm 45.0 cal guns - 108.92lbs / 49.41kg shells, 100 per gun
     Breech loading guns in deck mounts, 1900 Model
     4 x Single mounts on centreline, evenly spread
      4 - 3.00" / 76.2 mm 50.0 cal guns - 14.29lbs / 6.48kg shells, 150 per gun
     Quick firing guns in deck mounts, 1900 Model
     4 x Single mounts on sides, evenly spread
      Weight of broadside 493 lbs / 224 kg
      Main Torpedoes
      8 - 17.7" / 450 mm, 16.40 ft / 5.00 m torpedoes - 0.579 t each, 4.636 t total
   In 4 sets of deck mounted side rotating tubes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.25" / 6 mm         -               -

   - Armoured deck - single deck:
   For and Aft decks: 0.50" / 13 mm
   Forecastle: 0.50" / 13 mm  Quarter deck: 0.50" / 13 mm

   - Conning towers: Forward 0.40" / 10 mm, Aft 0.00" / 0 mm

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 6,398 ihp / 4,773 Kw = 21.00 kts
   Range 4,000nm at 10.00 kts
   Bunker at max displacement = 334 tons (100% coal)

Complement:
   123 - 160

Cost:
   £0.176 million / $0.705 million

Distribution of weights at normal displacement:
   Armament: 86 tons, 5.6 %
      - Guns: 77 tons, 5.0 %
      - Weapons: 9 tons, 0.6 %
   Armour: 52 tons, 3.4 %
      - Armament: 3 tons, 0.2 %
      - Armour Deck: 48 tons, 3.1 %
      - Conning Tower: 1 tons, 0.1 %
   Machinery: 764 tons, 49.4 %
   Hull, fittings & equipment: 394 tons, 25.5 %
   Fuel, ammunition & stores: 245 tons, 15.9 %
   Miscellaneous weights: 4 tons, 0.3 %
      - Above deck: 4 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     527 lbs / 239 Kg = 4.9 x 6.0 " / 152 mm shells or 0.6 torpedoes
   Stability (Unstable if below 1.00): 1.33
   Metacentric height 1.1 ft / 0.3 m
   Roll period: 10.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.56
   Seaboat quality  (Average = 1.00): 1.22

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.495 / 0.506
   Length to Beam Ratio: 11.54 : 1
   'Natural speed' for length: 17.32 kts
   Power going to wave formation at top speed: 48 %
   Trim (Max stability = 0, Max steadiness = 100): 58
   Bow angle (Positive = bow angles forward): 0.00 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 %,  13.00 ft / 3.96 m,  10.00 ft / 3.05 m
      - Forward deck:   30.00 %,  10.00 ft / 3.05 m,  10.00 ft / 3.05 m
      - Aft deck:   35.00 %,  7.00 ft / 2.13 m,  7.00 ft / 2.13 m
      - Quarter deck:   15.00 %,  7.00 ft / 2.13 m,  7.00 ft / 2.13 m
      - Average freeboard:      8.74 ft / 2.66 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 174.3 %
      - Above water (accommodation/working, high = better): 64.0 %
   Waterplane Area: 5,174 Square feet or 481 Square metres
   Displacement factor (Displacement / loading): 68 %
   Structure weight / hull surface area: 46 lbs/sq ft or 225 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.96
      - Longitudinal: 1.36
      - Overall: 1.00
   Cramped machinery, storage, compartmentation space
   Cramped accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

[Jefgte]

As for seakeeping - The bow wave height of this ship at 21 kts is only 2.59 ft.
In a sea of 5 ft waves in H[1/3] state- the minimum bow height required for 10% wetness is 7.39 ft.
In a sea of 10 ft waves in H[1/3] state - the minimum bow height required for 10% wetness is 9.38 ft.

Where did you find this numbers in SS ?

[snip]

In addition to the aforementioned comments, I feel the ship suffers from NEDS.

[Logi]

As for seakeeping - The bow wave height of this ship at 21 kts is only 2.59 ft.
In a sea of 5 ft waves in H[1/3] state- the minimum bow height required for 10% wetness is 7.39 ft.
In a sea of 10 ft waves in H[1/3] state - the minimum bow height required for 10% wetness is 9.38 ft.

Where did you find this numbers in SS ?

I didn't get those from SS, though the inputs were from the SS. I used the programs I created and posted in the Knowledge Base->Wave Tools thread which are based on empirical equations derived by other naval architects and are used in Universities like TU Delft. There shouldn't be a problem as SS uses familiar formulas to derive it's equations.

However, if you plan to take a look at the programs, I would wait ~ 1 hr. I need to go and insert a wait on completion so they don't auto-exit on calculation completion.

In addition to the aforementioned comments, I feel the ship suffers from NEDS.

How so? To accommodate 1 more 6" gun on the centerline, the ship length has growth 20'. I would thing that's more than enough space.

[snip]

I was referring to the old design that had 7x6" guns. The new one must have been edited in after I replied.

At this point, I would just strip the armor and make the ship lighter overall. Those thicknesses are going to do very little against any projectile. If it is supposed to be a "supper" DD, build it as light as you can.

[Logi]

I was referring to the old design that had 7x6" guns. The new one must have been edited in after I replied.

Yes I was reworking the new design for some time so you might have missed it.

At this point, I would just strip the armor and make the ship lighter overall. Those thicknesses are going to do very little against any projectile. If it is supposed to be a "supper" DD, build it as light as you can.

The first post 1900 design I did was no armor at 1200 tons - that's about as light as feasibly possible. For the new design the lightest possible would be around 1170 tons. I'ld rather have splinter armor for 80 tons in that case.

As KWorld mentioned, the purpose of the armor is to contain penetrations by stopping splinters - not to reject any sort of shell.

[Logi]

As for seakeeping - The bow wave height of this ship at 21 kts is only 2.59 ft.
In a sea of 5 ft waves in H[1/3] state- the minimum bow height required for 10% wetness is 7.39 ft.
In a sea of 10 ft waves in H[1/3] state - the minimum bow height required for 10% wetness is 9.38 ft.

Where did you find this numbers in SS ?

I didn't get those from SS, though the inputs were from the SS. I used the programs I created and posted in the Knowledge Base->Wave Tools thread which are based on empirical equations derived by other naval architects and are used in Universities like TU Delft. There shouldn't be a problem as SS uses familiar formulas to derive it's equations.

However, if you plan to take a look at the programs, I would wait ~ 1 hr. I need to go and insert a wait on completion so they don't auto-exit on calculation completion.

On another note, I've fix the Wave Tool programs. The specific order I used for the calculations above is Tasaki Model -> Alternative China Classification Society Model. Feel free to give feedback or ask questions about them.