Torpedo Boat Illustration

[Guinness]

This isn't done right, and I may have been staring at it too long, but...

I've had a hell of a time getting the hull lines to look right in the plan view, so I decided to ask for second, (and third, and fourth) opinions:



Basically an illustration of a 680ish ton torpedo boat. Just trying to get the hang of springsharping and illustrating torpedo craft.

[Sachmle]

Without seeing the equivilant SS Report to compare I really don't know if she looks like she's supposed to, but she looks nice.

[P3D]

Forecastle should be one full deck (7-8') above the weather deck.

[Borys]

Ahoj!
The stack is too croocked. There are no lifeboats. There should be some sort of mainmast.
Borys

[Guinness]

Now that I know I won't have 1912 engine tech for another year, I might as well share the SS:

This was really an exercise to see how small I could get a TB with how much firepower. As to the forcastle, as you can see, I was trying to get maximum freeboard there, but there isn't really room for 2 decks. Hence the stepping porthole line. This is actually just one of at least 3 designs I'm kicking around, this being the smallest, and 1000t (my maximum) being the largest.

The illustration isn't finished yet (still coming: some sort of main mast arrangement, ladders, some sort of FC, etc.)

1913 Torpedo Ram, CSA Torpedo Ram laid down 1913 (Engine 1912)

Displacement:
   680 t light; 709 t standard; 769 t normal; 818 t full load

Dimensions: Length overall / water x beam x draught
   259.82 ft / 255.00 ft x 22.00 ft x 10.55 ft (normal load)
   79.19 m / 77.72 m x 6.71 m  x 3.22 m

Armament:
      2 - 4.00" / 102 mm guns in single mounts, 25.00lbs / 11.34kg shells, 1910 Model
     Quick firing guns in deck mounts
     on centreline, all aft, 1 raised mount aft
      1 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1910 Model
     Quick firing gun in deck mount
     on centreline forward
      4 - 2.24" / 57.0 mm guns in single mounts, 5.65lbs / 2.56kg shells, 1910 Model
     Quick firing guns in deck mounts
     on side, evenly spread, all raised mounts
      2 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1913 Model
     Anti-aircraft guns in deck mounts
     on side, evenly spread
   Weight of broadside 105 lbs / 48 kg
   Shells per gun, main battery: 200
   6 - 20.0" / 508 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.50" / 13 mm         -               -
   2nd:   0.50" / 13 mm         -               -

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 20,318 shp / 15,157 Kw = 30.50 kts
   Range 3,500nm at 10.00 kts
   Bunker at max displacement = 109 tons

Complement:
   72 - 94

Cost:
   £0.101 million / $0.402 million

Distribution of weights at normal displacement:
   Armament: 15 tons, 1.9 %
   Armour: 3 tons, 0.4 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 3 tons, 0.4 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 400 tons, 52.0 %
   Hull, fittings & equipment: 231 tons, 30.0 %
   Fuel, ammunition & stores: 90 tons, 11.7 %
   Miscellaneous weights: 31 tons, 4.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     169 lbs / 77 Kg = 5.3 x 4.0 " / 102 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.05
   Metacentric height 0.6 ft / 0.2 m
   Roll period: 12.3 seconds
   Steadiness   - As gun platform (Average = 50 %): 60 %
         - Recoil effect (Restricted arc if above 1.00): 0.43
   Seaboat quality  (Average = 1.00): 1.07

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0.455
   Length to Beam Ratio: 11.59 : 1
   'Natural speed' for length: 15.97 kts
   Power going to wave formation at top speed: 70 %
   Trim (Max stability = 0, Max steadiness = 100): 56
   Bow angle (Positive = bow angles forward): 15.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      18.00 ft / 5.49 m
      - Forecastle (20 %):   17.00 ft / 5.18 m (11.00 ft / 3.35 m aft of break)
      - Mid (50 %):      11.00 ft / 3.35 m
      - Quarterdeck (15 %):   11.00 ft / 3.35 m
      - Stern:      11.00 ft / 3.35 m
      - Average freeboard:   12.28 ft / 3.74 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 187.2 %
      - Above water (accommodation/working, high = better): 34.7 %
   Waterplane Area: 3,593 Square feet or 334 Square metres
   Displacement factor (Displacement / loading): 43 %
   Structure weight / hull surface area: 24 lbs/sq ft or 119 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 3.65
      - Overall: 0.61
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is extremely poor

Misc Weights:
6 tons (torpedos)
25 tons (fire control)

Cost $1.2625

[Jefgte]

"Room for accommodation and workspaces is extremely poor"

6 TT, that's too much on the deck.

The speed is certainly too higher reduce to have:
"Ship has slow, easy roll, a good, steady gun platform"

Thanks for the crew
   

Jef  ;)

[Korpen]

"Room for accommodation and workspaces is extremely poor"

6 TT, that's too much on the deck.

The speed is certainly too higher reduce to have:
"Ship has slow, easy roll, a good, steady gun platform"

I think i disagree with all of Jefgte;s points.
She is an offensive ship, so she will not need long loiter times, so accommodations are not a big issue, speed is more valuable. Her stability is not that great, so trying to increase steadiness would seem unwise, in fact I think I should trim her up to 1,10 stability if possible, if necessary sacrificing some sea keeping.

Speed is fine, in fact i think even more would be better :)

[Guinness]

"Room for accommodation and workspaces is extremely poor"

6 TT, that's too much on the deck.

The speed is certainly too higher reduce to have:
"Ship has slow, easy roll, a good, steady gun platform"

I think i disagree with all of Jefgte;s points.
She is an offensive ship, so she will not need long loiter times, so accommodations are not a big issue, speed is more valuable. Her stability is not that great, so trying to increase steadiness would seem unwise, in fact I think I should trim her up to 1,10 stability if possible, if necessary sacrificing some sea keeping.

Speed is fine, in fact i think even more would be better :)

31 knots is possible on about 700t it seems. 32 knots needs  a bit bigger hull.

[miketr]

I got 33 knots on a 1,000 ton hull the problem is it had no range and little in the way of weapons besides the torps.

Speaking of range, the 3500 nm might be light.  Figure out what your combat range is (range at full speed).

Michael

[Korpen]

I got 33 knots on a 1,000 ton hull the problem is it had no range and little in the way of weapons besides the torps.

Speaking of range, the 3500 nm might be light.  Figure out what your combat range is (range at full speed).

Michael

Hm, managed 34,5 on 1000 ton with 3x10cm guns and a range of 220nm at top speed (~4000nm@12kts). But her seakeeping is from hell (1,0 at 29kts).

[Guinness]

As it is now, she's got ranges of:

10 knots    3500
20 knots      615
30 knots     175
30.5 knots  166

So I'll have to do a little research and think about how much range she really needs. An more bunkerage in this design is going to mean a bigger hull. If I add a little draft, I can get 200 miles at 30 knots. If I do that and give up a stern 4" gun, I can get 225 miles at 30 knots. If I give up the gun and 3 torpedos, then it's 225 miles at 30 knots.

I'm sure if I landed the FC, I could get more, but reducing the fighting strength isn't really what I'm looking for. I could go over 700 tons though, of course.

So maybe a good conversation item is: what is a useful combat radius for a TB?

[Desertfox]

Get rid of the FC, that is one thing you do not need.

[The Rock Doctor]

The historical German GTB1913 class, displacing  975 - 1188 t, had a range of 1100 to 1800 miles at 20 knots.

I designed the newest GC thousand tonner with 6,800 nm @ 10 knots.  This was around eleven or twelve hours at flank speed, as I recall.  It also gives bunkerage figures comparable to similar-sized British pre-war boats.

[Guinness]

Another crack at it, sans FC:

1913 Torpedo Ram, CSA Torpedo Ram laid down 1913 (Engine 1912)

Displacement:
   670 t light; 699 t standard; 790 t normal; 863 t full load

Dimensions: Length overall / water x beam x draught
   264.82 ft / 260.00 ft x 23.15 ft x 10.10 ft (normal load)
   80.72 m / 79.25 m x 7.06 m  x 3.08 m

Armament:
      2 - 4.00" / 102 mm guns in single mounts, 25.00lbs / 11.34kg shells, 1910 Model
     Quick firing guns in deck mounts
     on centreline, all aft, 1 raised mount aft
      1 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1910 Model
     Quick firing gun in deck mount
     on centreline forward
      4 - 2.24" / 57.0 mm guns in single mounts, 5.65lbs / 2.56kg shells, 1910 Model
     Breech loading guns in deck mounts
     on side, evenly spread, all raised mounts
      2 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1913 Model
     Anti-aircraft guns in deck mounts
     on side, evenly spread
   Weight of broadside 105 lbs / 48 kg
   Shells per gun, main battery: 200
   6 - 20.0" / 508 mm above water torpedoes

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 20,511 shp / 15,302 Kw = 30.50 kts
   Range 5,300nm at 10.00 kts
   Bunker at max displacement = 164 tons

Complement:
   73 - 96

Cost:
   £0.103 million / $0.411 million

Distribution of weights at normal displacement:
   Armament: 15 tons, 1.9 %
   Machinery: 417 tons, 52.7 %
   Hull, fittings & equipment: 232 tons, 29.4 %
   Fuel, ammunition & stores: 120 tons, 15.2 %
   Miscellaneous weights: 6 tons, 0.8 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     194 lbs / 88 Kg = 6.1 x 4.0 " / 102 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.25
   Metacentric height 0.8 ft / 0.3 m
   Roll period: 10.6 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.29
   Seaboat quality  (Average = 1.00): 1.05

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0.455
   Length to Beam Ratio: 11.23 : 1
   'Natural speed' for length: 16.12 kts
   Power going to wave formation at top speed: 70 %
   Trim (Max stability = 0, Max steadiness = 100): 48
   Bow angle (Positive = bow angles forward): 15.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      18.00 ft / 5.49 m
      - Forecastle (20 %):   17.00 ft / 5.18 m (11.00 ft / 3.35 m aft of break)
      - Mid (50 %):      11.00 ft / 3.35 m
      - Quarterdeck (15 %):   11.00 ft / 3.35 m
      - Stern:      11.00 ft / 3.35 m
      - Average freeboard:   12.28 ft / 3.74 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 185.8 %
      - Above water (accommodation/working, high = better): 41.7 %
   Waterplane Area: 3,855 Square feet or 358 Square metres
   Displacement factor (Displacement / loading): 45 %
   Structure weight / hull surface area: 25 lbs/sq ft or 120 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 3.15
      - Overall: 0.60
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is extremely poor

Misc Weights:
6 tons (torpedoes)
Range at top speed: 250

Cost $1.2875

[Valles]

My view has always been that destroyer fire control actually had very little to do with the ship's guns, but was intended as a way of increasing the accuracy of its torpedoes.

Which would, once again, put me utterly opposite Desertfox on a point of design philosophy - keeping the fire control would be a must, in my mind. ^_^