Indochinese - Sloop-of-all-trades

[hooper82]

So, the Indochinese navy desperately needs a replacement for the sloops that Glorious France donated.  The idea is to build a class of ship that has the following primary roles -

* Coastal Patrol & Customs
* Auxiliary/Freighter Escort
* Showing the flag inside the Indochinese sphere of influence

Considering the small build capacity and low number of slips Indochina has, it'd be nice if it could carry out these secondary roles -

* Coastal/Harbor Defense
* Torpedo Boat

So, I've come up with the following!

Instead of going the traditional 'heaviest guns I can fit on this hull' route I decided that any guns sub-800t design could mount would never penetrate armor of any ship of note.  Instead, lets fit more, smaller, faster firing guns.  The idea being that the smaller twin 3.1" guns (concentrated at the bow of the ship) will fire rapidly using HE/AP into the superstructure of the enemy combatant, trying to disrupt its operations and let it get close enough to loose 3 21" torpedoes into their side.

Against Destroyers who are generally unarmored, and surfaced subs, 3.1" guns will penetrate just fine.  The 40mm twin mountings can depress enough to fire at coning towers/small boats/etc.

These boats have lots of 'extras'.  Long range Wireless and a well sized bunker (for a ship of there sized) giving them a good patrol/escort time.  Depth Charges and a ridiculously heavy AA armament (for the time) to ward off subs and air-ships.  2 well sized boats and space for 30 Marines for boarding/scouting parties.

But, they are slow, have no armor, and I suspect under gunned?

Anyway, seeing as this is my first home-grown design, I'd love to hear peoples thoughts.

UNNAMED, Indochina Sloop laid down 1916 (Engine 1912)

Displacement:
   776 t light; 808 t standard; 981 t normal; 1,119 t full load

Dimensions: Length overall / water x beam x draught
   300.05 ft / 295.28 ft x 29.53 ft x 9.84 ft (normal load)
   91.46 m / 90.00 m x 9.00 m  x 3.00 m

Armament:
      6 - 3.15" / 80.0 mm guns (3x2 guns), 15.62lbs / 7.09kg shells, 1916 Model
     Quick firing guns in deck mounts with hoists
     on centreline ends, majority forward, 2 raised mounts - superfiring
      4 - 1.57" / 40.0 mm guns (2x2 guns), 1.98lbs / 0.90kg shells, 1916 Model
     Anti-aircraft guns in deck mounts
     on centreline, all aft, all raised mounts - superfiring
      2 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1916 Model
     Machine guns in deck mounts
     on side, evenly spread
   Weight of broadside 102 lbs / 46 kg
   Shells per gun, main battery: 200
   3 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.79" / 20 mm   0.39" / 10 mm            -

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 3,000 shp / 2,238 Kw = 18.62 kts
   Range 6,000nm at 12.00 kts
   Bunker at max displacement = 311 tons

Complement:
   86 - 113

Cost:
   £0.089 million / $0.357 million

Distribution of weights at normal displacement:
   Armament: 13 tons, 1.3 %
   Armour: 6 tons, 0.6 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 6 tons, 0.6 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 120 tons, 12.2 %
   Hull, fittings & equipment: 498 tons, 50.8 %
   Fuel, ammunition & stores: 204 tons, 20.8 %
   Miscellaneous weights: 140 tons, 14.3 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,939 lbs / 880 Kg = 124.1 x 3.1 " / 80 mm shells or 1.0 torpedoes
   Stability (Unstable if below 1.00): 1.07
   Metacentric height 0.9 ft / 0.3 m
   Roll period: 13.0 seconds
   Steadiness   - As gun platform (Average = 50 %): 79 %
         - Recoil effect (Restricted arc if above 1.00): 0.33
   Seaboat quality  (Average = 1.00): 1.57

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.400
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 17.18 kts
   Power going to wave formation at top speed: 40 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      13.12 ft / 4.00 m
      - Forecastle (20 %):   9.84 ft / 3.00 m
      - Mid (50 %):      9.84 ft / 3.00 m
      - Quarterdeck (15 %):   9.84 ft / 3.00 m
      - Stern:      9.84 ft / 3.00 m
      - Average freeboard:   10.10 ft / 3.08 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 66.4 %
      - Above water (accommodation/working, high = better): 89.3 %
   Waterplane Area: 5,367 Square feet or 499 Square metres
   Displacement factor (Displacement / loading): 201 %
   Structure weight / hull surface area: 56 lbs/sq ft or 273 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 1.18
      - Longitudinal: 1.96
      - Overall: 1.24
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is cramped
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

* 12t for Torpedoes (6 total, 1 reload)
* 25t for Fire Control
* 25t for Long Range Wireless
* 8t for 24 Depth Charges & 2 Rails
* 10t for 2 Small Boats
* 60t for 30 Marines (Not embarked when on escort duties)

[Guinness]

Hull strength (Relative):
      - Cross-sectional: 1.18
      - Longitudinal: 1.96
      - Overall: 1.24

It actually looks like this ship has a lot of overhead for more stuff. Maybe a little more speed is possible?

[mentat]

The alternative (if you are really happy with current speed) is a bit smaller and cheaper?

But, overall I agree with Guiness - more speed would be very useful (say 22-24 knots min.) - esp. in the TB attack role, also the existing bunkerage is excessive given quite low fuel consumption at 18 knots 

Depending on the Nos you are planning - scope for a hi-lo mix of 2 related designs?

[Carthaginian]

I think you should pour on that speed.
Might make a proper frigate out of her if you do... 24+ knots.
If you can get her above 24 knots, then you can use the DD construction rules, and there's no telling how fast you can get her while still maintaining above 1.00 seakeeping.

[Guinness]

Cost may be an issue, in which case sticking to the regular ship rules might be the way to go too.

[hooper82]

Aye, I want this to fall under the regular ship rules instead of TB/DD rules.

Revised, more engine power, not much else changed.  Only up to 21.5 knots.

UNNAMED, Indochina Sloop laid down 1916 (Engine 1912)

Displacement:
   776 t light; 808 t standard; 981 t normal; 1,119 t full load

Dimensions: Length overall / water x beam x draught
   300.05 ft / 295.28 ft x 29.53 ft x 9.84 ft (normal load)
   91.46 m / 90.00 m x 9.00 m  x 3.00 m

Armament:
      6 - 3.15" / 80.0 mm guns (3x2 guns), 15.62lbs / 7.09kg shells, 1916 Model
     Quick firing guns in deck mounts with hoists
     on centreline ends, majority forward, 2 raised mounts - superfiring
      4 - 1.57" / 40.0 mm guns (2x2 guns), 1.98lbs / 0.90kg shells, 1916 Model
     Anti-aircraft guns in deck mounts
     on centreline, all aft, all raised mounts - superfiring
      2 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1916 Model
     Machine guns in deck mounts
     on side, evenly spread
   Weight of broadside 102 lbs / 46 kg
   Shells per gun, main battery: 200
   3 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.79" / 20 mm   0.39" / 10 mm            -

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 5,200 shp / 3,879 Kw = 21.54 kts
   Range 6,000nm at 12.00 kts
   Bunker at max displacement = 311 tons

Complement:
   86 - 113

Cost:
   £0.109 million / $0.438 million

Distribution of weights at normal displacement:
   Armament: 13 tons, 1.3 %
   Armour: 6 tons, 0.6 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 6 tons, 0.6 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 207 tons, 21.1 %
   Hull, fittings & equipment: 410 tons, 41.8 %
   Fuel, ammunition & stores: 204 tons, 20.8 %
   Miscellaneous weights: 140 tons, 14.3 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,322 lbs / 600 Kg = 84.6 x 3.1 " / 80 mm shells or 0.6 torpedoes
   Stability (Unstable if below 1.00): 1.02
   Metacentric height 0.8 ft / 0.3 m
   Roll period: 13.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 95 %
         - Recoil effect (Restricted arc if above 1.00): 0.41
   Seaboat quality  (Average = 1.00): 1.46

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.400
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 17.18 kts
   Power going to wave formation at top speed: 48 %
   Trim (Max stability = 0, Max steadiness = 100): 65
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      13.12 ft / 4.00 m
      - Forecastle (20 %):   9.84 ft / 3.00 m
      - Mid (50 %):      9.84 ft / 3.00 m
      - Quarterdeck (15 %):   9.84 ft / 3.00 m
      - Stern:      9.84 ft / 3.00 m
      - Average freeboard:   10.10 ft / 3.08 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 94.9 %
      - Above water (accommodation/working, high = better): 89.3 %
   Waterplane Area: 5,367 Square feet or 499 Square metres
   Displacement factor (Displacement / loading): 148 %
   Structure weight / hull surface area: 46 lbs/sq ft or 225 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.59
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is cramped
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

* 12t for Torpedoes (6 total, 1 reload)
* 25t for Fire Control
* 25t for Long Range Wireless
* 8t for 24 Depth Charges & 2 Rails
* 10t for 2 Small Boats
* 60t for 30 Marines (Not embarked when on escort duties)

[Sachmle]

I'd lower your trim. 95% steadiness is overkill, 70% is great. Also this will increase your stability and 1.10 is considered the 'unspoken' "Good" spot.

[mentat]

  Looking good - very cheap and very useful - even if limited in attack mode.

   Agree with Sachmle on the trim tweaking.

   How many you plan to build ?  :)

[P3D]

The guns would be outranged by anything, and honestly there's not much utility of fire control with 3" guns. Might have chance against one or two small-to-medium torpedo boats but not any other naval ships.
If you want a sloop, I'd suggest 160mm guns, and more misc weight for mines/minesweeping equipment, with some minimal armor (25mm belt 15mm deck).

[Jefgte]

6x80 guns are not the best choice.
3 bigger caliber guns are certainly better.


;)

[maddox]

There is a reason that almost all the French ships have the QF 140mm with heavy shells . 

Also, Indochina is developing an 80mm gun?
I don't get it. Just develop a heavy shell for the all present 70mm. Ok, still  1.5 kg lighter than the potential 80mm gun. But less development cost.

And otherwise, the 105mm is also a reasonable standard gun for the Indochinese marine.

[hooper82]

Also, Indochina is developing an 80mm gun?
I don't get it. Just develop a heavy shell for the all present 70mm. Ok, still  1.5 kg lighter than the potential 80mm gun. But less development cost.

I like being unique.

Just to clarify, this is not a destroyer.  Its primary mission isn't fleet operations.  I'm planning on building a separate destroyer class.  Think of this as a DE.  If this class is engaging in fleet actions...then Indochina is in a bad way.


Revised Design below
* 3x2 3" guns replaced with 3x1 4.7"
* Doubled Depth Charge Capacity
* 40t added for Mine Sweeping Gear (is that enough?  Nothing in rules about whats needed for mine sweeping equipment)
* Engines reduced back to 3000HP (18.622 knots)

UNNAMED, Indochina Sloop laid down 1916 (Engine 1912)

Displacement:
   769 t light; 808 t standard; 981 t normal; 1,119 t full load

Dimensions: Length overall / water x beam x draught
   300.05 ft / 295.28 ft x 29.53 ft x 9.84 ft (normal load)
   91.46 m / 90.00 m x 9.00 m  x 3.00 m

Armament:
      3 - 4.72" / 120 mm guns in single mounts, 52.72lbs / 23.92kg shells, 1916 Model
     Quick firing guns in deck mounts with hoists
     on centreline ends, majority forward, 2 raised mounts - superfiring
      4 - 1.57" / 40.0 mm guns (2x2 guns), 1.98lbs / 0.90kg shells, 1916 Model
     Anti-aircraft guns in deck mounts
     on centreline, all aft, all raised mounts - superfiring
      2 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1916 Model
     Machine guns in deck mounts
     on side, evenly spread
   Weight of broadside 166 lbs / 75 kg
   Shells per gun, main battery: 200
   3 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.18" / 30 mm   0.59" / 15 mm            -

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 3,000 shp / 2,238 Kw = 18.62 kts
   Range 6,000nm at 12.00 kts
   Bunker at max displacement = 311 tons

Complement:
   86 - 113

Cost:
   £0.100 million / $0.400 million

Distribution of weights at normal displacement:
   Armament: 21 tons, 2.1 %
   Armour: 9 tons, 0.9 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 9 tons, 0.9 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 120 tons, 12.2 %
   Hull, fittings & equipment: 432 tons, 44.1 %
   Fuel, ammunition & stores: 212 tons, 21.6 %
   Miscellaneous weights: 188 tons, 19.2 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,664 lbs / 755 Kg = 31.6 x 4.7 " / 120 mm shells or 0.8 torpedoes
   Stability (Unstable if below 1.00): 1.09
   Metacentric height 0.9 ft / 0.3 m
   Roll period: 12.7 seconds
   Steadiness   - As gun platform (Average = 50 %): 64 %
         - Recoil effect (Restricted arc if above 1.00): 0.48
   Seaboat quality  (Average = 1.00): 1.57

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.400
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 17.18 kts
   Power going to wave formation at top speed: 40 %
   Trim (Max stability = 0, Max steadiness = 100): 41
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      13.12 ft / 4.00 m
      - Forecastle (20 %):   9.84 ft / 3.00 m
      - Mid (50 %):      9.84 ft / 3.00 m
      - Quarterdeck (15 %):   9.84 ft / 3.00 m
      - Stern:      9.84 ft / 3.00 m
      - Average freeboard:   10.10 ft / 3.08 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 77.9 %
      - Above water (accommodation/working, high = better): 89.3 %
   Waterplane Area: 5,367 Square feet or 499 Square metres
   Displacement factor (Displacement / loading): 163 %
   Structure weight / hull surface area: 49 lbs/sq ft or 237 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.94
      - Longitudinal: 1.65
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is excellent
   Room for accommodation and workspaces is cramped
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

* 12t for Torpedoes (6 total, 1 reload)
* 25t for Fire Control
* 25t for Long Range Wireless
* 16t for 48 Depth Charges & 2 Rails
* 40t for Minesweeping Gear
* 10t for 2 Small Boats
* 60t for 30 Marines (Not embarked when on escort duties)

[maddox]

The "unique" thing ain't bad, just pricey.

With a speed of 18 kts, you could try Diesel propulsion- same engines as subs. 

Also, you have the capacity to 2 size 0 ships ,and 3 type 2 ships.
Now you will have to sacrifice the build capacity of the 170m length docks to build 91m long ships.

If you can shrink them to 70m long ships, it would be a better use of your infrastructure.

[Jefgte]

...Its primary mission isn't fleet operations...

She works alone...
Police & fishing assistance (?)


Built a DE or an half DD are perhaps a good alternative.
24kts-3x120-3TT & overall is 0.56  :)


  ;)

[mentat]

The dock infrastructure aspect seems to suggest a hi-lo mix - I guess 4 x 80mm (you are so keen on :D) - would fit on a 70m hull and to compensate - you could stretch the existing larger version to carry 4 x 105mm or 120mm - 4 guns is better than 3 ...

I think the 21+ knots makes them handier for more tasks/sitns