Not true, maddox. According to Conway's 1922-1946, (only source I've been able to find them in), over 1,000 were built by the Italians. They went 28-33 knots, carried 1-2 450 mm torpedoes, and sometimes carried depth charges and smoke canisters, as well as a .5'' Browning.

Quote from: Nobody on April 24, 2010, 06:22:08 AM
According to my observation there are a few actually really simple reasons why Springsharp has increasing problems when the ship in question gets smaller:

• all values are rounded to full tons before the hull strength is calculated
  
• the engines power to weight ratio is not adjusted to ship and/or engine size
  
• engine type is ignored, so especially MTBs are a problem
  

The other main issue with using SpringSharp to sim MTBs is that SS assumes the vessel is made of high grade industrial steel, not wood, nor aluminum or fiberboard, or any of the other things MTBs were built from. Anyone w/ relevant technical specifications for MTBs could try simming them, see what weight it takes to make it work, then divide that by the 'actual' weight. See if there is a correspondent to it, like SS weight is ~ususally 2x the actual or whatever it comes out to, then we could just say "Sim your MTB, divide SS weight by 2 and that would be the actual weight. I don't have the references to try this myself.

Also, IIRC, doesn't SS assume pure-displacement hulls no matter what speed or hull form are used? MTBs were usually planing hulls, weren't they?

Quote from: Valles on April 24, 2010, 11:45:54 AM
Also, IIRC, doesn't SS assume pure-displacement hulls no matter what speed or hull form are used? MTBs were usually planing hulls, weren't they?

AFIK, they were all planing hulls.
That, I think, is the biggest problem with simming the MTBs and other small vessels in Springsharp- no ability to chose planing or semi-planing hulls.

I think the problem is engine weight, as I have been able to sim ships as small as 5 tons in SS2 with no problem as long as speed is kept low.

@ TC, I think the MTBs you are talking about are actually 15 tons. Th two torpedoes alone weight about 2 tons.

http://books.google.com/books?id=bJBMBvyQ83EC&printsec=frontcover&dq=conways+1922-1946&source=bl&ots=6WjjRKpErI&sig=TLlnJ4FLh5G08VRCQTomJLJgqHg&hl=en&ei=jLLTS9yODZK09QTB2r3ADw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAgQ6AEwAA#v=onepage&q=conways%201922-1946&f=false

Link to Conways 1922-1946. The information is on Page 315.

Those are not true MTBs, they are little more than manned surfaced torpedoes. Think Kaiten.

Yeah... these things are more like the suicide boat that hit the Cole.
There IS 1 1.7t TB in the next column, though, and it is a true TB and does have a planing hull.

That's what I was talking about...sorry for the confusion.

Quote from: Carthaginian on April 25, 2010, 05:34:35 AM
Yeah... these things are more like the suicide boat that hit the Cole.
There IS 1 1.7t TB in the next column, though, and it is a true TB and does have a planing hull.

I wonder is that 1.7 Metric Tons or 1.7 English Standard Tons :)

In addition 1000 were not made 4 were.  They have a range of 90 nm so they can putter out of a port putter around for a few hours and then putter back into port at no point do they get more then  maybe 40 miles from port.  These are not miniture MTB they a harbor defense craft and the launch mechanism for the torpedoes is horrible.

Quote from: ctwaterman on April 27, 2010, 09:47:53 PM

Quote from: Carthaginian on April 25, 2010, 05:34:35 AM
There IS 1 1.7t TB in the next column, though, and it is a true TB and does have a planing hull.

I wonder is that 1.7 Metric Tons or 1.7 English Standard Tons :)

One way or the other, she's basically a bass boat with torpedoes strapped on. ;)

But total, the MTS, the MTSM, and the MTSMA had about 1,000 units.

I read the history of S-130 yesterday and wanted to see what they would like in SS2, though I knew they would not work out well.

Bear in mind, OTL these boats had "only" 6000 to 7500 hp!

---

First I tried to set values close to reality, I forgot about the speed calculator and only added the value later.
S-Boot, Germany Speedboat laid down 1942
DESIGN FAILURE: Overall load weight too much for hull

Displacement:
   93 t light; 96 t standard; 110 t normal; 121 t full load

Dimensions: Length overall / water x beam x draught
   111,55 ft / 111,55 ft x 16,40 ft x 5,25 ft (normal load)
   34,00 m / 34,00 m x 5,00 m  x 1,60 m

Armament:
      1 - 1,46" / 37,0 mm guns in single mounts, 1,55lbs / 0,70kg shells, 1942 Model
     Anti-aircraft gun in deck mount
     on centreline forward
      1 - 0,79" / 20,0 mm guns in single mounts, 0,24lbs / 0,11kg shells, 1942 Model
     Anti-aircraft gun in deck mount
     on centreline aft
   Weight of broadside 2 lbs / 1 kg
   Shells per gun, main battery: 500
   2 - 21,0" / 533,4 mm above water torpedoes

Armour:
   - Conning tower: 0,59" / 15 mm

Machinery:
   Diesel Internal combustion motors,
   Direct drive, 3 shafts, 26.562 shp / 19.815 Kw = 39,00 kts
   Range 700nm at 20,00 kts
   Bunker at max displacement = 26 tons
     Caution: Delicate, lightweight machinery

Complement:
   16 - 22

Cost:
   £0,088 million / $0,352 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0,2%
   Armour: 0 tons, 0,3%
      - Belts: 0 tons, 0,0%
      - Torpedo bulkhead: 0 tons, 0,0%
      - Armament: 0 tons, 0,0%
      - Armour Deck: 0 tons, 0,0%
      - Conning Tower: 0 tons, 0,3%
   Machinery: 74 tons, 67,7%
   Hull, fittings & equipment: 18 tons, 16,3%
   Fuel, ammunition & stores: 17 tons, 15,5%
   Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     5 lbs / 2 Kg = 3,4 x 1,5 " / 37 mm shells or 0,1 torpedoes
   Stability (Unstable if below 1.00): 1,20
   Metacentric height 0,5 ft / 0,1 m
   Roll period: 10,1 seconds
   Steadiness   - As gun platform (Average = 50 %): 7 %
         - Recoil effect (Restricted arc if above 1.00): 0,01
   Seaboat quality  (Average = 1.00): 0,01

Hull form characteristics:
   Hull has a flush deck
     and transom stern
   Block coefficient: 0,400
   Length to Beam Ratio: 6,80 : 1
   'Natural speed' for length: 12,66 kts
   Power going to wave formation at top speed: 92 %
   Trim (Max stability = 0, Max steadiness = 100): 75
   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:      11,61 ft / 3,54 m
      - Forecastle (20%):   7,38 ft / 2,25 m
      - Mid (50%):      7,38 ft / 2,25 m
      - Quarterdeck (15%):   7,38 ft / 2,25 m
      - Stern:      7,38 ft / 2,25 m
      - Average freeboard:   7,72 ft / 2,35 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 220,2%
      - Above water (accommodation/working, high = better): 25,4%
   Waterplane Area: 1.169 Square feet or 109 Square metres
   Displacement factor (Displacement / loading): 8%
   Structure weight / hull surface area: 8 lbs/sq ft or 37 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,09
      - Longitudinal: 2,91
      - Overall: 0,13
   Hull space for machinery, storage, compartmentation is extremely poor
   Room for accommodation and workspaces is extremely poor
   Ship has quick, lively roll, not a steady gun platform
   Caution: Lacks seaworthiness - very limited seakeeping ability

Trial Speed: 45.77

---

And this one after I was reminded of the speed calculator:
S-Boot, Germany Speedboat laid down 1942
DESIGN FAILURE: Overall load weight too much for hull

Displacement:
   93 t light; 96 t standard; 110 t normal; 121 t full load

Dimensions: Length overall / water x beam x draught
   111,55 ft / 111,55 ft x 16,40 ft x 5,25 ft (normal load)
   34,00 m / 34,00 m x 5,00 m  x 1,60 m

Armament:
      1 - 1,46" / 37,0 mm guns in single mounts, 1,55lbs / 0,70kg shells, 1942 Model
     Anti-aircraft gun in deck mount
     on centreline forward
      1 - 0,79" / 20,0 mm guns in single mounts, 0,24lbs / 0,11kg shells, 1942 Model
     Anti-aircraft gun in deck mount
     on centreline aft
   Weight of broadside 2 lbs / 1 kg
   Shells per gun, main battery: 500
   2 - 21,0" / 533,4 mm above water torpedoes

Armour:
   - Conning tower: 0,59" / 15 mm

Machinery:
   Diesel Internal combustion motors,
   Direct drive, 3 shafts, 15.922 shp / 11.878 Kw = 35,00 kts
   Range 700nm at 20,00 kts
   Bunker at max displacement = 26 tons
     Caution: Delicate, lightweight machinery

Complement:
   16 - 22

Cost:
   £0,084 million / $0,336 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0,2%
   Armour: 0 tons, 0,3%
      - Belts: 0 tons, 0,0%
      - Torpedo bulkhead: 0 tons, 0,0%
      - Armament: 0 tons, 0,0%
      - Armour Deck: 0 tons, 0,0%
      - Conning Tower: 0 tons, 0,3%
   Machinery: 70 tons, 63,6%
   Hull, fittings & equipment: 22 tons, 20,4%
   Fuel, ammunition & stores: 17 tons, 15,5%
   Miscellaneous weights: 0 tons, 0,0%

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     10 lbs / 4 Kg = 6,3 x 1,5 " / 37 mm shells or 0,1 torpedoes
   Stability (Unstable if below 1.00): 1,15
   Metacentric height 0,4 ft / 0,1 m
   Roll period: 10,5 seconds
   Steadiness   - As gun platform (Average = 50 %): 11 %
         - Recoil effect (Restricted arc if above 1.00): 0,01
   Seaboat quality  (Average = 1.00): 0,03

Hull form characteristics:
   Hull has a flush deck
     and transom stern
   Block coefficient: 0,400
   Length to Beam Ratio: 6,80 : 1
   'Natural speed' for length: 12,66 kts
   Power going to wave formation at top speed: 90 %
   Trim (Max stability = 0, Max steadiness = 100): 75
   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:      11,61 ft / 3,54 m
      - Forecastle (20%):   7,38 ft / 2,25 m
      - Mid (50%):      7,38 ft / 2,25 m
      - Quarterdeck (15%):   7,38 ft / 2,25 m
      - Stern:      7,38 ft / 2,25 m
      - Average freeboard:   7,72 ft / 2,35 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 207,1%
      - Above water (accommodation/working, high = better): 25,4%
   Waterplane Area: 1.169 Square feet or 109 Square metres
   Displacement factor (Displacement / loading): 13%
   Structure weight / hull surface area: 9 lbs/sq ft or 46 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,16
      - Longitudinal: 3,64
      - Overall: 0,22
   Hull space for machinery, storage, compartmentation is extremely poor
   Room for accommodation and workspaces is extremely poor
   Ship has quick, lively roll, not a steady gun platform
   Caution: Lacks seaworthiness - very limited seakeeping ability

Trial Speed: 41.36

I was kind of surprised that their composite strength still ended up above 0 despite the ridiculous machinery. I was also surprised that reducing the speed by 4 knots makes no real difference.

The problem with Springsharp is that it doesn't recognize planing hulls.

Yes, and we don't normally use transom sterns either. But one of the interesting things about the S-Boats is that they didn't have planing hulls. Which is why I thought I could give this a try.