Iberian Torpedo Boat

[miketr]

I am thinking of building a small torpedo boat for the philippines and western med.  Something I could build in larger numbers than the 750 ton design.  I came out with this but I am not exactly happy with it.  Any suggestions?

TB-1909-S, Iberia Torpedo Boat laid down 1909

Displacement:
   402 t light; 414 t standard; 434 t normal; 451 t full load

Dimensions: Length overall / water x beam x draught
   202.82 ft / 200.00 ft x 20.00 ft x 7.60 ft (normal load)
   61.82 m / 60.96 m x 6.10 m  x 2.32 m

Armament:
      1 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1909 Model
     Quick firing gun in deck mount
     on centreline forward, 1 raised gun
      2 - 1.97" / 50.0 mm guns in single mounts, 3.81lbs / 1.73kg shells, 1909 Model
     Quick firing guns in deck mounts
     on centreline, all aft, 1 raised mount
   Weight of broadside 20 lbs / 9 kg
   Shells per gun, main battery: 250
   2 - 18.0" / 457.2 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.00" / 25 mm         -               -
   2nd:   1.00" / 25 mm         -               -

Machinery:
   Coal fired boilers, steam turbines,
   Direct drive, 2 shafts, 10,188 shp / 7,601 Kw = 27.00 kts
   Range 1,000nm at 10.00 kts
   Bunker at max displacement = 37 tons (100% coal)

Complement:
   46 - 61

Cost:
   £0.049 million / $0.196 million

Distribution of weights at normal displacement:
   Armament: 3 tons, 0.6 %
   Armour: 3 tons, 0.8 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 3 tons, 0.8 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 233 tons, 53.7 %
   Hull, fittings & equipment: 150 tons, 34.6 %
   Fuel, ammunition & stores: 33 tons, 7.5 %
   Miscellaneous weights: 12 tons, 2.8 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     138 lbs / 62 Kg = 10.7 x 3.0 " / 75 mm shells or 0.2 torpedoes
   Stability (Unstable if below 1.00): 1.11
   Metacentric height 0.5 ft / 0.2 m
   Roll period: 11.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 72 %
         - Recoil effect (Restricted arc if above 1.00): 0.16
   Seaboat quality  (Average = 1.00): 1.20

Hull form characteristics:
   Hull has raised forecastle, rise forward of midbreak
   Block coefficient: 0.500
   Length to Beam Ratio: 10.00 : 1
   'Natural speed' for length: 14.14 kts
   Power going to wave formation at top speed: 73 %
   Trim (Max stability = 0, Max steadiness = 100): 60
   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:      16.00 ft / 4.88 m
      - Forecastle (20 %):   15.00 ft / 4.57 m (14.50 ft / 4.42 m aft of break)
      - Mid (50 %):      13.00 ft / 3.96 m (10.00 ft / 3.05 m aft of break)
      - Quarterdeck (15 %):   10.00 ft / 3.05 m
      - Stern:      10.00 ft / 3.05 m
      - Average freeboard:   12.21 ft / 3.72 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 181.4 %
      - Above water (accommodation/working, high = better): 96.7 %
   Waterplane Area: 2,665 Square feet or 248 Square metres
   Displacement factor (Displacement / loading): 41 %
   Structure weight / hull surface area: 21 lbs/sq ft or 102 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 6.53
      - Overall: 0.65
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

[Ithekro]

You probably don't need that much armor on the gun mounts.  A half inch will probably stop splinters and small arms fire.

[P3D]

As half of the hull weight is machinery, I'd build it a bit bigger. Armor is 3t, the W/T is 15. Not much else to cut.

[miketr]

As half of the hull weight is machinery, I'd build it a bit bigger. Armor is 3t, the W/T is 15. Not much else to cut.

Bigger goes against the cheap'o idea that is the core of this design.  I am trying to create the smallest design possible and won't suffer from the NS TB's problems.  I think this is it but I was hoping someone might have something better.  I'm fairly sure a full 500 ton design would be better just not sure how much.

Michael

[Ithekro]

Something based on a historical design.  This is a destroyer if you can believe it.

Capitan Thompson

Chilean Destroyer laid down 1898 (Engine 1910)

Displacement:
289 t light; 299 t standard; 350 t normal; 389 t full load

Dimensions: Length overall / water x beam x draught
214.00 ft / 213.00 ft x 21.50 ft x 5.33 ft (normal load)
65.23 m / 64.92 m x 6.55 m x 1.62 m

Armament:
1 - 2.88" / 73.3 mm guns in single mounts, 12.00lbs / 5.44kg shells, 1898 Model
Quick firing gun in deck mount
on centreline forward
5 - 2.29" / 58.2 mm guns in single mounts, 6.00lbs / 2.72kg shells, 1898 Model
Quick firing guns in deck mounts
on side, evenly spread
Weight of broadside 42 lbs / 19 kg
Shells per gun, main battery: 100
2 - 18.0" / 457.2 mm above water torpedoes

Machinery:
Coal fired boilers, complex reciprocating steam engines,
Direct drive, 2 shafts, 6,465 ihp / 4,823 Kw = 25.25 kts
Range 1,150nm at 15.00 kts (Bunkerage = 92 tons)

Complement:
39 - 52

Cost:
£0.041 million / $0.162 million

Distribution of weights at normal displacement:
Armament: 5 tons, 1.5 %
Machinery: 186 tons, 53.2 %
Hull, fittings & equipment: 93 tons, 26.5 %
Fuel, ammunition & stores: 61 tons, 17.4 %
Miscellaneous weights: 5 tons, 1.4 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
91 lbs / 41 Kg = 7.6 x 2.9 " / 73 mm shells or 0.1 torpedoes
Stability (Unstable if below 1.00): 1.20
Metacentric height 0.7 ft / 0.2 m
Steadiness - As gun platform (Average = 50 %): 75 %
- Recoil effect (Restricted arc if above 1.00): 0.16
Seaboat quality (Average = 1.00): 0.79

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.502
Length to Beam Ratio: 9.91 : 1
'Natural speed' for length: 14.59 kts
Power going to wave formation at top speed: 67 %
Trim (Max stability = 0, Max steadiness = 100): 95
Bow angle (Positive = bow angles forward): 4.75 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 12.00 ft / 3.66 m
- Forecastle (20 %): 9.00 ft / 2.74 m
- Mid (50 %): 8.00 ft / 2.44 m
- Quarterdeck (15 %): 8.00 ft / 2.44 m
- Stern: 8.00 ft / 2.44 m
- Average freeboard: 8.59 ft / 2.62 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 184.5 %
- Above water (accommodation/working, high = better): 92.0 %
Waterplane Area: 2,939 Square feet or 273 Square metres
Displacement factor (Displacement / loading): 39 %
Structure weight / hull surface area: 18 lbs/sq ft or 88 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 1.16
- Overall: 0.54
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

[The Rock Doctor]

Mike, if you're willing to cut down on the seakeeping (1.20 is pretty high for a small destroyer), you've got room to scale the design down.

I think it is fairly capable for its size - the speed is good, the range adequate for defensive work.  If you're willing to accept a smaller, slower vessel (which is still faster than most capital ships), I'd direct you to my thread on Riverine Torpedo Boats on page 3 of this forum.

[Desertfox]

Bigger goes against the cheap'o idea that is the core of this design.  I am trying to create the smallest design possible and won't suffer from the NS TB's problems.  I think this is it but I was hoping someone might have something better.  I'm fairly sure a full 500 ton design would be better just not sure how much.

Mike, if you're willing to cut down on the seakeeping (1.20 is pretty high for a small destroyer), you've got room to scale the design down.

Unfortunately P3D seems to think differently. According to him any DD less than 750tons is totaly worthless in anything less than calm seas.

[P3D]

According to him any DD less than 750tons is totaly worthless in anything less than calm seas.

How horrible! A small ship can make only 20knots in 15' waves although it has the SHP to do 30! Outrageous! Unrealistic!

[maddox]

Desertfox, I don't think you have ever been at sea on a small vessel.

I have, a 35foot length 9 foot wide all steel work boat.  When the weather was fine, going all out was just fast and noisy ,15 Kts, the diesel vibrating everything, including my teeth.
But when the chop came up, we had to trottle down because things became alive, pitch, roll and yawn all at the same time, I never forget the feeling of disorientation. 
During the return trip, we had to trottle all out to keep the bow into the waves, and not making much headway.

Now, that isn't much compared to a 1905 750 tons DD.
On the other side, the workboat was build in 1958,and re-engined in 1984, I personaly welded on the trimkeels in 1992, and when we were busy, replaced all the zink anodes, remade the rudder into a balanced one (huge difference, less load on the steering mechanisme and better handling.)

To make a long story short.  You cannot push a 750 tons DD trough 15" waves at 25 kts, and not suffer damages that will cripple the ship.  The "advantage" of DD tech is that you're allowed to build ships with less than 1 composite hullstrength. 
Disadvantage is that these ships are weak hulled, and can be damaged in heavy weather.Will be damaged in hurricanes or Typhoons.(as mod I kept this at a minimum in the Nverse 2, and we didn't get that into the Nverse 3, but the "idea" still stands) Pushing such a vessel trough less than mirror like seas at top speed will feel as if the small waves are a lot bigger.

[Carthaginian]

Unfortunately P3D seems to think differently. According to him any DD less than 750tons is totaly worthless in anything less than calm seas.

DF, I have many friends that have 25' fishing boats that weigh in at less than a ton and are capable of over 70 knots... in calm water. However, as soon as you get more than a 2 foot chop, they drop down to about 10 knots, or they will flip over. Granted, they are planing hulls instead of displacement hulls, but I'm sure that you see the point.

Just because they have the horsepower to make insane speeds under perfect conditions does not mean that they can keep that up whent hey are 'out of their element.' Destroyers are no different than those race boats with rod holders... they are built with 'optimal conditions' in mind.


My own 500t boats are coastal designs for just that reason- they can't operate in inclement weather anywhere except protected waters without struggling to stay afloat, much less in a condition that would allow combat operations. I mean, how can I expect a 200' destroyer to make 27.5 knots in waves that are 10% it's own length? I'll be happy if they can even patrol AT ALL in those conditions! Even my 750t designs will be hard-pressed to do battle on the open sea; they just lack the moxie to handle rough weather.

Perhaps when I reach 1000t I'll be able to build a decent 'fleet destroyer'... but for the moment, that is just a design concept who's time has not yet come.

[Korpen]

To make a long story short.  You cannot push a 750 tons DD trough 15" waves at 25 kts, and not suffer damages that will cripple the ship.  The "advantage" of DD tech is that you're allowed to build ships with less than 1 composite hullstrength. 
Disadvantage is that these ships are weak hulled, and can be damaged in heavy weather.Will be damaged in hurricanes or Typhoons.(as mod I kept this at a minimum in the Nverse 2, and we didn't get that into the Nverse 3, but the "idea" still stands) Pushing such a vessel trough less than mirror like seas at top speed will feel as if the small waves are a lot bigger.

Well now i will make a sidetrack again.
But one major reason for destroyers to have "weaker" hulls is that Springsharp makes much of the equipment on fast small ships excessively heavy (esp. the engines).

Sure a destroyer is lighter built then a cruiser, but a cruiser is also far lighter built then a dreadnought. All thing equal, the smaller the ship, the lighter its construction.

[Carthaginian]

Oh, and I think she's an excellent design, Mike... good for close-in work in the many channels and sounds in the Pacific archepelegos. Great speed for the calm Pacific summers as well... though like my TR-200's, the tropical weather season will likely make them seek out shelter.

[maddox]

Well now i will make a sidetrack again.
But one major reason for destroyers to have "weaker" hulls is that Springsharp makes much of the equipment on fast small ships excessively heavy (esp. the engines).

The 1910 tech for engines isn't light to start with. And every increase of speed needs a lot of extra Hp.

Sure a destroyer is lighter built then a cruiser, but a cruiser is also far lighter built then a dreadnought. All thing equal, the smaller the ship, the lighter its construction.

That is represented by the composite hull strength. If a ship has less than 1, the guideline is that it becomes vurnable to heavy weather if handled not perfectly right.
You can build a 1 composite hull strength DD and make it as large as you want.... (looking at the faster NS designs)

[Tanthalas]

I cant realy coment on small boat preformance in heavy seas, my only experiance with small craft in heavy seas is on a LCAC (shouldnt count isnt realy a boat) and a Scarab that we rented in Australia once.  The Scarab isnt realy a fair comparison because well it actualy preforms better in heavy seas, the more of the hull you can get out of the watter the faster it is lol.  That said at 60 kts the damn thing was still scary as hell.

[Ithekro]

On a semi-related side note: on Saturday I played a modified version of General Quarters 3.  We used order cards for movement, gunnery, changes in orders, torpede launches, torpedo movement, damage control, and detection.  One stack of cards gave us three turns worth of everything, but in a random order.  This however lead to something interesting.  We would write our orders based on a compass heading and speed rather than adjusting by points on the turn marker.  Since our orders could be spread rather far apart (or several one after another without actaully moving) we've normally set our speeds at far less than flank (especially since this was a night action).  If we had moved at flank our forces would have missed each other quite easily, or even with our fleets having detected each other, our course was set until the next orders card came up, so be still might miss an opportune turn or sail right into a torpedo or warship.  As it was the French managed to torpedo one of their own ships (one heavy cruiser actually torpedoed herself, the danger of using very fast cruisers but setting your torpedoes on the slowest setting, then turning into the torpedoes path) and the Italians torpedoed one of their own destroyers and almost torpedoed one of their own cruisers (the cruisers out ran the torpedos, but that shot had been a calculated risk, unlike the French incidents).  The Italians managed to torpedo one of the French cruisers and the French torpedoed an Italian cruiser.  Only one French destroyer was  blown apart by Italian guns after it was rammed by an Italian cruiser.

The orders by heading made the battle look a whole lot like the plots one sees in all those books on various historical naval actions.  But it also set in us that battles are not always held at flank speed.  The only time our ships went full out was when they were deciding to run or give chase, and even that was almost more trouble than it was worth.  (Only the Italian destroyers went to flank for that side, the French when tot flank earlier and left the field (38 knot destroyers) as well as a flank speed turn to get out of the path of the Italian cruiser, which did not work.  The French heavy cruiser managed to outrun her own torpedoes and the light cruiser was rammed by the Italian heavy cruiser, the torpedoed by Italian destroyers.  Both sank.