Early Era Test

[Nobody]

Tried to do an very early torpedoboat. It was supposed to be no more than 80 to 85 tons. Can some else do better?


T1880,  Torpedoboat laid down 1880

Displacement:
   80 t light; 82 t standard; 90 t normal; 95 t full load

Dimensions: Length overall / water x beam x draught
   118,11 ft / 118,11 ft x 10,50 ft x 6,56 ft (normal load)
   36,00 m / 36,00 m x 3,20 m  x 2,00 m

Armament:
      1 - 1,97" / 50,0 mm guns in single mounts, 3,24lbs / 1,47kg shells, 1880 Model
     Breech loading gun in deck mount
     on centreline forward
   Weight of broadside 3 lbs / 1 kg
   Shells per gun, main battery: 100
   2 - 13,8" / 350 mm above water torpedoes

Machinery:
   Coal fired boilers, simple reciprocating steam engines,
   Direct drive, 1 shaft, 1.449 ihp / 1.081 Kw = 20,10 kts
   Range 300nm at 12,00 kts
   Bunker at max displacement = 13 tons (100% coal)
     Caution: Delicate, lightweight machinery

Complement:
   13 - 18

Cost:
   £0,011 million / $0,044 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0,5%
   Machinery: 56 tons, 62,4%
   Hull, fittings & equipment: 23 tons, 25,9%
   Fuel, ammunition & stores: 9 tons, 10,1%
   Miscellaneous weights: 1 tons, 1,1%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     10 lbs / 4 Kg = 3,0 x 2,0 " / 50 mm shells or 0,0 torpedoes
   Stability (Unstable if below 1.00): 1,02
   Metacentric height 0,2 ft / 0,1 m
   Roll period: 10,5 seconds
   Steadiness   - As gun platform (Average = 50 %): 51 %
         - Recoil effect (Restricted arc if above 1.00): 0,07
   Seaboat quality  (Average = 1.00): 0,94

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0,385
   Length to Beam Ratio: 11,25 : 1
   'Natural speed' for length: 10,87 kts
   Power going to wave formation at top speed: 64 %
   Trim (Max stability = 0, Max steadiness = 100): 55
   Bow angle (Positive = bow angles forward): -10,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      8,20 ft / 2,50 m
      - Forecastle (30%):   7,22 ft / 2,20 m (3,94 ft / 1,20 m aft of break)
      - Mid (50%):      3,61 ft / 1,10 m
      - Quarterdeck (25%):   3,61 ft / 1,10 m
      - Stern:      3,61 ft / 1,10 m
      - Average freeboard:   4,84 ft / 1,48 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 205,8%
      - Above water (accommodation/working, high = better): 20,1%
   Waterplane Area: 715 Square feet or 66 Square metres
   Displacement factor (Displacement / loading): 15%
   Structure weight / hull surface area: 13 lbs/sq ft or 62 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,50
      - Longitudinal: 2,22
      - Overall: 0,58
   Caution: Hull subject to strain in open-sea
   Hull space for machinery, storage, compartmentation is extremely poor
   Room for accommodation and workspaces is extremely poor
   Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

[Korpen]

Tried to do an very early torpedoboat. It was supposed to be no more than 80 to 85 tons. Can some else do better?

I do not know if it is so much better, but at least it is smaller. Not a ship for long periods out at sea.

1880-1, Nordic TB laid down 1880

Displacement:
   65 t light; 67 t standard; 75 t normal; 82 t full load

Dimensions: Length overall / water x beam x draught
   116,47 ft / 116,47 ft x 11,15 ft x 5,18 ft (normal load)
   35,50 m / 35,50 m x 3,40 m  x 1,58 m

Armament:
      1 - 1,46" / 37,0 mm guns in single mounts, 1,31lbs / 0,60kg shells, 1880 Model
     Quick firing gun in deck mount
     on centreline amidships
   Weight of broadside 1 lbs / 1 kg
   Shells per gun, main battery: 150
   1 - 13,8" / 350 mm above water torpedoes, 1 - 13,8" / 350 mm submerged torpedo tubes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0,20" / 5 mm         -               -

Machinery:
   Coal fired boilers, simple reciprocating steam engines,
   Direct drive, 1 shaft, 1 280 ihp / 955 Kw = 20,00 kts
   Range 400nm at 12,00 kts
   Bunker at max displacement = 15 tons (100% coal)
     Caution: Delicate, lightweight machinery

Complement:
   12 - 16

Cost:
   £0,009 million / $0,036 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0,2 %
   Armour: 0 tons, 0,2 %
      - Belts: 0 tons, 0,0 %
      - Torpedo bulkhead: 0 tons, 0,0 %
      - Armament: 0 tons, 0,2 %
      - Armour Deck: 0 tons, 0,0 %
      - Conning Tower: 0 tons, 0,0 %
   Machinery: 47 tons, 63,0 %
   Hull, fittings & equipment: 17 tons, 22,4 %
   Fuel, ammunition & stores: 10 tons, 13,1 %
   Miscellaneous weights: 1 tons, 1,1 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     5 lbs / 2 Kg = 3,8 x 1,5 " / 37 mm shells or 0,0 torpedoes
   Stability (Unstable if below 1.00): 1,11
   Metacentric height 0,2 ft / 0,1 m
   Roll period: 9,8 seconds
   Steadiness   - As gun platform (Average = 50 %): 41 %
         - Recoil effect (Restricted arc if above 1.00): 0,02
   Seaboat quality  (Average = 1.00): 0,44

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,390
   Length to Beam Ratio: 10,44 : 1
   'Natural speed' for length: 10,79 kts
   Power going to wave formation at top speed: 66 %
   Trim (Max stability = 0, Max steadiness = 100): 78
   Bow angle (Positive = bow angles forward): 0,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      5,74 ft / 1,75 m
      - Forecastle (25 %):   4,59 ft / 1,40 m
      - Mid (30 %):      3,28 ft / 1,00 m
      - Quarterdeck (15 %):   3,28 ft / 1,00 m
      - Stern:      3,28 ft / 1,00 m
      - Average freeboard:   3,76 ft / 1,15 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 261,4 %
      - Above water (accommodation/working, high = better): 30,7 %
   Waterplane Area: 751 Square feet or 70 Square metres
   Displacement factor (Displacement / loading): 14 %
   Structure weight / hull surface area: 12 lbs/sq ft or 58 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,50
      - Longitudinal: 0,90
      - Overall: 0,53
   Caution: Hull subject to strain in open-sea
   Hull space for machinery, storage, compartmentation is extremely poor
   Room for accommodation and workspaces is extremely poor
   Caution: Lacks seaworthiness - very limited seakeeping ability

[Kaiser Kirk]

More surprisingly, there is no difference between the two concerning fuel consumption at all! That's the opposite of what I would have expected.

One of SS's deficits is they all seem to have the same fuel consumption.  OTL, as I recall Electric drive was ~20% more efficient than DD, and ~9% more than reduction gearing which helped offset it's roughly 10% greater weight and suggests a 10% fuel efficiency gain at each step...though I think that was all with Turbines. I'd have to dig it up to say for sure.

[Nobody]

More surprisingly, there is no difference between the two concerning fuel consumption at all! That's the opposite of what I would have expected.

One of SS's deficits is they all seem to have the same fuel consumption.

Not all. If you use only turbine/diesel the fuel consumption is slightly lower.

OTL, as I recall Electric drive was ~20% more efficient than DD, and ~9% more than reduction gearing which helped offset it's roughly 10% greater weight and suggests a 10% fuel efficiency gain at each step...though I think that was all with Turbines. I'd have to dig it up to say for sure.

I don't know about the efficiency but I have a source which says that electric drive was ~25% heavier than geared drive - at least around 1935. The difference for diesels was ~15% at that time. Also worth tho note is that just before and during WW1 the diesel drive was considered cheaper and lighter than a turbine power plant.

[Korpen]

OTL, as I recall Electric drive was ~20% more efficient than DD, and ~9% more than reduction gearing which helped offset it's roughly 10% greater weight and suggests a 10% fuel efficiency gain at each step...though I think that was all with Turbines. I'd have to dig it up to say for sure.

I am pretty certain that huge difference only applies to turbines as DD turbines spin the propeller at a higher then optimum speed; a condition that is not present in reciprocating engines.

[Nobody]

OTL, as I recall Electric drive was ~20% more efficient than DD, and ~9% more than reduction gearing which helped offset it's roughly 10% greater weight and suggests a 10% fuel efficiency gain at each step...though I think that was all with Turbines. I'd have to dig it up to say for sure.

I am pretty certain that huge difference only applies to turbines as DD turbines spin the propeller at a higher then optimum speed; a condition that is not present in reciprocating engines.

The German small cruisers might be interesting to look at, because for a couple of years they build ships with turbines and triple expansion engines in the same class. From what I remember the turbine driven ships carried more coal and had a lower range at cruising speed.

[Korpen]

OTL, as I recall Electric drive was ~20% more efficient than DD, and ~9% more than reduction gearing which helped offset it's roughly 10% greater weight and suggests a 10% fuel efficiency gain at each step...though I think that was all with Turbines. I'd have to dig it up to say for sure.

I am pretty certain that huge difference only applies to turbines as DD turbines spin the propeller at a higher then optimum speed; a condition that is not present in reciprocating engines.

The German small cruisers might be interesting to look at, because for a couple of years they build ships with turbines and triple expansion engines in the same class. From what I remember the turbine driven ships carried more coal and had a lower range at cruising speed.

Seems reasonable, as turbines in general seems to be less economical then reciprocating engines at low power levels, DD or not.

[Nobody]

Now this is the "recreation" of an actual ship (except that I don't know the rage or the freeboard).
Note the extremely fine hull!

http://en.wikipedia.org/wiki/A_class_torpedo_boat
A I (A 1-25), German Empire Torpedoboat laid down 1914

Displacement:
   100 t light; 102 t standard; 110 t normal; 116 t full load

Dimensions: Length overall / water x beam x draught
   134,51 ft / 134,51 ft x 16,40 ft x 4,92 ft (normal load)
   41,00 m / 41,00 m x 5,00 m  x 1,50 m

Armament:
      1 - 1,97" / 50,0 mm guns in single mounts, 3,81lbs / 1,73kg shells, 1914 Model
     Breech loading gun in deck mount
     on centreline forward
   Weight of broadside 4 lbs / 2 kg
   Shells per gun, main battery: 100
   2 - 17,7" / 450 mm above water torpedoes

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 1 shaft, 1.200 ihp / 896 Kw = 19,35 kts
   Range 600nm at 12,00 kts
   Bunker at max displacement = 14 tons (100% coal)

Complement:
   16 - 22

Cost:
   £0,015 million / $0,060 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0,4%
   Machinery: 56 tons, 50,9%
   Hull, fittings & equipment: 43 tons, 38,8%
   Fuel, ammunition & stores: 10 tons, 9,0%
   Miscellaneous weights: 1 tons, 0,9%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     49 lbs / 22 Kg = 12,8 x 2,0 " / 50 mm shells or 0,1 torpedoes
   Stability (Unstable if below 1.00): 1,15
   Metacentric height 0,4 ft / 0,1 m
   Roll period: 10,4 seconds
   Steadiness   - As gun platform (Average = 50 %): 57 %
         - Recoil effect (Restricted arc if above 1.00): 0,02
   Seaboat quality  (Average = 1.00): 0,72

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0,355
   Length to Beam Ratio: 8,20 : 1
   'Natural speed' for length: 11,60 kts
   Power going to wave formation at top speed: 62 %
   Trim (Max stability = 0, Max steadiness = 100): 80
   Bow angle (Positive = bow angles forward): -10,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      6,56 ft / 2,00 m
      - Forecastle (25%):   6,56 ft / 2,00 m (4,59 ft / 1,40 m aft of break)
      - Mid (50%):      3,94 ft / 1,20 m
      - Quarterdeck (20%):   3,94 ft / 1,20 m
      - Stern:      3,94 ft / 1,20 m
      - Average freeboard:   4,68 ft / 1,43 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 168,6%
      - Above water (accommodation/working, high = better): 34,1%
   Waterplane Area: 1.262 Square feet or 117 Square metres
   Displacement factor (Displacement / loading): 68%
   Structure weight / hull surface area: 22 lbs/sq ft or 105 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,95
      - Longitudinal: 1,68
      - Overall: 1,00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is extremely poor
   Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

[Korpen]

Now this is the "recreation" of an actual ship (except that I don't know the rage or the freeboard).
Note the extremely fine hull!

I also noted that issue of extremely low BC when looking at the early Danish TBs http://www.orlogsmuseet.dk/T/pages/Torpedobaad%20No.4(1879).htm . That card makes me wonder exactly what the sources mean by "Draught", as in the case of the Danish boat there is a 1,2m difference between the draught at the stem and the stern. I suspect that the higher number is the clearance for the propellers, rather then the depth of the keel.