Support Cruiser

[Valles]

The idea is for an at least relatively low-cost vessel capable of serving as an oiler, fleet tender, torpedo boat mothership, hospital ship, or whatever.

The problem is that I have absolutely no clue how to design one in SS.

Anyone have advice to offer?

[Tanthalas]

Use the tender rules, atleast thats what I did

[maddox]

Springsharp II has a problem with large misc weight allocations.

For colliers and oilers it's simple to adjust, increase range and/or cruise speed to get huge bunkers in a ship, those don't turn a ship over.

But for tenders/troop ships and such, it's less easy to do.

[Valles]

Something like this?

Penitent Son, Maori Support Cruiser laid down 1911 (Engine 1909)

Displacement:
   20,116 t light; 20,709 t standard; 29,636 t normal; 36,777 t full load

Dimensions: Length overall / water x beam x draught
   559.09 ft / 551.18 ft x 91.86 ft x 22.97 ft (normal load)
   170.41 m / 168.00 m x 28.00 m  x 7.00 m

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 2 shafts, 22,258 shp / 16,605 Kw = 18.00 kts
   Range 50,000nm at 10.00 kts
   Bunker at max displacement = 16,068 tons

Complement:
   1,129 - 1,468

Cost:
   £0.846 million / $3.383 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.0 %
   Machinery: 1,012 tons, 3.4 %
   Hull, fittings & equipment: 6,605 tons, 22.3 %
   Fuel, ammunition & stores: 9,520 tons, 32.1 %
   Miscellaneous weights: 12,500 tons, 42.2 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     55,600 lbs / 25,220 Kg = 514.8 x 6 " / 152 mm shells or 4.8 torpedoes
   Stability (Unstable if below 1.00): 1.12
   Metacentric height 5.4 ft / 1.7 m
   Roll period: 16.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 100 %
         - Recoil effect (Restricted arc if above 1.00): 0.00
   Seaboat quality  (Average = 1.00): 2.00

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.892
   Length to Beam Ratio: 6.00 : 1
   'Natural speed' for length: 23.48 kts
   Power going to wave formation at top speed: 42 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      26.25 ft / 8.00 m
      - Forecastle (20 %):   22.97 ft / 7.00 m
      - Mid (50 %):      22.97 ft / 7.00 m
      - Quarterdeck (15 %):   22.97 ft / 7.00 m
      - Stern:      22.97 ft / 7.00 m
      - Average freeboard:   23.23 ft / 7.08 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 57.9 %
      - Above water (accommodation/working, high = better): 184.7 %
   Waterplane Area: 47,674 Square feet or 4,429 Square metres
   Displacement factor (Displacement / loading): 204 %
   Structure weight / hull surface area: 106 lbs/sq ft or 516 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.97
      - Longitudinal: 1.33
      - 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
   Excellent seaboat, comfortable, rides out heavy weather easily

Actual purpose-built bunkers total ~3,000 tons. The rest of the bunkerage is repurposable cargo space.

This configuration is for the 'tender/oiler' role. More typical would be a configuration with lighter repair facilities below the waterline and torpedo boat carriage above. Other roles include hospital ship (1,800 beds) and pure cargo (26,000 tons capacity).

[maddox]

Except the size, it's a good example.

20Ktons ligth is "huge". 10Ktons is "large".

[Valles]

That's the partially loaded weight including tender equipment, 'tho admittedly I'd need to pay for that as though it were 'real tonnage'. Per the 'distribution of weights' section, the actual weight of the hull, engines, etc. is about 7,600 tons.

Hm... *toddles off to try it in SS3 to get a more accurate look*

[Korpen]

Except the size, it's a good example.

20Ktons ligth is "huge". 10Ktons is "large".

Well in line with Maori designs then, as they tend towards gigantism. :)

[The Rock Doctor]

Are we talking about another "multi-purpose" ship whose contents are changed according to the mission?

[Valles]

That's the intent, yes. There was a previous attempt?

[The Rock Doctor]

Foxy did some work on ~gunboats which were intended to have some modular equipment.  There was some controversy about it; I find the concept premature, myself, but I think the mods consider it OK.

I'd be thinking that there'd be considerable loss of efficiency resulting from the different functions requiring different...geometry.  Bulk cargo can make do with a large, cavernous hold, but a field hospital would need floors built into the hold, otherwise there'd be a lot of wasted volume.

You might have to spend a good deal of time (and, perhaps, money) cleaning out a space and then configuring it for the new contents, too - coal dust or oil vapors wouldn't be good for hospital patients.

I recognize that gigantism is an apparent Maori trait, but I don't see an advantage over three smaller vessels that could undertake different functions in different locations.

[Valles]

I'm not picturing them as being hot-swappable. Turning, say, a battleship tender into a hospital ship would involve weeks to months in a drydock, taking the deck off, unbolting the oil tanks and machinery, lifting it out, and dropping people-scale decks in their place.

The scale was chosen because the requirements for a battleship-tender seem to demand such if sea and handling characteristics are also to be achieved.

[The Rock Doctor]

Gotcha.  Hot-swapping was my concern - in the long-term, changing the function is not difficult to imagine so long as the facility's available and you can afford to have 'er out of service for the duration of the swaps.

[Valles]

Thunder Rage, Maori Support Cruiser laid down 1911 (Engine 1909)

Displacement:
   8,002 t light; 8,271 t standard; 13,460 t normal; 17,611 t full load

Dimensions: Length overall / water x beam x draught
   393.71 ft / 387.14 ft x 55.77 ft x 22.97 ft (normal load)
   120.00 m / 118.00 m x 17.00 m  x 7.00 m

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 2 shafts, 14,626 shp / 10,911 Kw = 18.00 kts
   Range 50,000nm at 10.00 kts
   Bunker at max displacement = 9,340 tons

Complement:
   624 - 812

Cost:
   £0.373 million / $1.493 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.0 %
   Machinery: 665 tons, 4.9 %
   Hull, fittings & equipment: 2,537 tons, 18.8 %
   Fuel, ammunition & stores: 5,458 tons, 40.6 %
   Miscellaneous weights: 4,800 tons, 35.7 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     19,398 lbs / 8,799 Kg = 179.6 x 6 " / 152 mm shells or 2.4 torpedoes
   Stability (Unstable if below 1.00): 0.96
   Metacentric height 1.9 ft / 0.6 m
   Roll period: 16.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 94 %
         - Recoil effect (Restricted arc if above 1.00): 0.00
   Seaboat quality  (Average = 1.00): 1.89

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.950
   Length to Beam Ratio: 6.94 : 1
   'Natural speed' for length: 19.68 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 2.53 ft / 0.77 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 %):      19.69 ft / 6.00 m
      - Quarterdeck (15 %):   19.69 ft / 6.00 m
      - Stern:      19.69 ft / 6.00 m
      - Average freeboard:   19.95 ft / 6.08 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 55.8 %
      - Above water (accommodation/working, high = better): 127.7 %
   Waterplane Area: 21,258 Square feet or 1,975 Square metres
   Displacement factor (Displacement / loading): 220 %
   Structure weight / hull surface area: 77 lbs/sq ft or 378 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.94
      - Longitudinal: 2.10
      - Overall: 1.02
   Caution: Poor stability - excessive risk of capsizing
   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
   Excellent seaboat, comfortable, rides out heavy weather easily

About half the empty mass of the previous attempt, about half the cost, about half the capacity, but fits in a slot one size smaller. A closer reading of the tender rules reveals that they judge by Misc Weight PLUS Fuel Weight, which'd mean that this could still support the battleships...

Enh. I don't exactly have a shortage of large slips, at least at the moment.

[P3D]

B.C. of 0.950? It has the hullform a brick, literally.

[The Rock Doctor]

That she does.

Stability is a problem, but setting the trim to around 30 or 35 should produce a value adequately above 1.00.