MTB Tech

[miketr]

Iberia is interested in buying the 1914 MTB tech if any nation is willing to sell.

A question for the mods, how much building capacity does it take to build a MTB?  Its 20 tons for the 1910 but is it going to take an entire type 0 slipway for such a tiny craft?  These are something that could be built in a factory inland and dropped on a train flat car for transport to the coast.

Michael

[Guinness]

MTBs are one of the types we had in mind when we cooked up the idea of a type X+ drydock, seen here:

http://www.navalism.org/index.php?topic=2965.0

[Sachmle]

@Guinness: Fair enough, but there is no 'size' listed for MTBs. Granted, SS can't sim an MTB so we're pretty much limited to historical designs :( so finding a length shouldn't be to hard. But, Miketr makes a decent point as to the 'factory' approach. Perhaps this is something to add to the 1922 Rules discussion?

[Kaiser Kirk]

Iberia is interested in buying the 1914 MTB tech if any nation is willing to sell.

Michael

Bavaria's one of the leaders in MTB tech, I'm sure we can find something mutually agreeable.

[Nobody]

Isn't that what the "under 200 ton" rule is for?

[Sachmle]

Isn't that what the "under 200 ton" rule is for?

No

These rules do not apply to small ships built to military standards, such as MTBs.  These will require slipways or docks in government shipyards.

[Guinness]

The under 200t ship rule:

Small ships

It is possible to build small ships (less than 201 t light displacement) to mercantile  standards without the use of dedicated military infrastructure.  Two options are available:

1)  If the land mass or region has a coastal town/city and industrial output of at least 0.5 BP, it may build one small ship each half-year.  For each additional 0.5 BP, the area may construct an additional small ship.  Dollar and BP costs remain the same as if built in a miiltary yard.

2)  If the land mass is without either a coastal town/city or the industrial output, the components of a small ship can be built and assembled elsewhere, transported to the desired location, and assembled.  The time and cost of construction will be equal to that of normal construction, plus a penalty to be determined by a Moderator based on the specific circumstances of the ship.

These rules do not apply to small ships built to military standards, such as MTBs.  These will require slipways or docks in government shipyards.

Note the last paragraph.

My guess is the longest historical MTB might have been German Schnellboot at ~ 33m. US PT Boats were no longer than 24m, British MTBs were no bigger than 21 or 22m, Italian boats apparently were typically less than 19m, and I think the French built some too.

Elco PT boats were 73' 4" at the waterline, and 20' 7" in beam, and drew at full load as much as 5' at the propellers, but the props hung 28" below the line of the hull. If I plug 2.8 feet into SS with a BC of 0.38, I get a Normal displacement of 46 tons which is in the realm of possibility since they weighed between 51 and 61 (presumably short) tons. So I think it might be possible to derive length, beam, and depth for the boats in our table, at least as a maximum. But for simplicity we can probably just assume that any MTB is 30m or less long, which will work fine with the rules as they are now.

The idea of factories have been reviewed in the past, but if we're going to have MTB factories, we might as well have tank factories, artillery factories, aircraft factories, etc. etc. I'm of the mind that all that extra bean counting wouldn't be worth it. I suppose one could think of it as "parts are manufactured elsewhere, even whole assemblies, which then get brought together in a dry dock". I see no reason that the same dock couldn't be used over and over again to produce MAS boats. Under current rules, such a boat would be launched in 3 months as it is, so even a Type 0+ DD could be used to produce 4 boats every half.

[Darman]

Out of curiousity, do we need to sim our MTBs?  or just use the standard ones in the Rules?

[Guinness]

Just use the standard ones in the chart, similar to subs. If you want to list additional design details for flavor, that's ok, but not required.

[Darman]

phew!  I've tried simming several and they all fail...

[miketr]

I wasn't suggesting a MTB factory just that I don't think they really use up ship building capacity.  For example some USN PT boats of WW2 were made as kits inland and then sent to a yard to be assembled there.  The game scale I think is sorta higher level than to account for the type of work for a MTB.  They are also so cheap compared to even the smallest TB.  I really don't think they should use any yard capacity.

Michael

[ledeper]

Those are my attempts to SS German S-boat:
http://www.navalism.org/index.php?topic=5315.0

[Darman]

this thread actually reminded me that I wanted to build a flotilla or two of MTBs for Egyptian Harbor defense...

[Jefgte]

 ???  ???  ???

Why special techno for MTB.
They are just small CTB.

Testing a SS with 1922/20 technos

MTB, NUS 90t laid down 1922 (Engine 1920)

Displacement:
   90 t light; 92 t standard; 99 t normal; 105 t full load

Dimensions: Length overall / water x beam x draught
   82.02 ft / 82.02 ft x 16.40 ft x 6.63 ft (normal load)
   25.00 m / 25.00 m x 5.00 m  x 2.02 m

Armament:
     1 - 1.57" / 40.0 mm guns in single mounts, 1.95lbs / 0.89kg shells, 1922 Model
     Quick firing gun in deck mount
     on centreline forward
     1 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1922 Model
     Machine gun in deck mount
     on centreline aft
   Weight of broadside 2 lbs / 1 kg
   Shells per gun, main battery: 100
   2 - 18.0" / 457.2 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:
   Petrol Internal combustion motors,
   Geared drive, 2 shafts, 6 000 shp / 4 476 Kw = 25.16 kts
   Range 180nm at 20.00 kts
   Bunker at max displacement = 13 tons
     Caution: Delicate, lightweight machinery

Complement:
   15 - 20

Cost:
   £0.031 million / $0.126 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.3 %
   Armour: 0 tons, 0.4 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 0 tons, 0.4 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 58 tons, 58.6 %
   Hull, fittings & equipment: 27 tons, 27.0 %
   Fuel, ammunition & stores: 10 tons, 9.6 %
   Miscellaneous weights: 4 tons, 4.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     19 lbs / 9 Kg = 9.8 x 1.6 " / 40 mm shells or 0.1 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 0.4 ft / 0.1 m
   Roll period: 10.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 13 %
         - Recoil effect (Restricted arc if above 1.00): 0.02
   Seaboat quality  (Average = 1.00): 0.06

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.390
   Length to Beam Ratio: 5.00 : 1
   'Natural speed' for length: 9.06 kts
   Power going to wave formation at top speed: 88 %
   Trim (Max stability = 0, Max steadiness = 100): 54
   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:      10.17 ft / 3.10 m
      - Forecastle (20 %):   8.53 ft / 2.60 m
      - Mid (50 %):      7.55 ft / 2.30 m
      - Quarterdeck (16 %):   6.89 ft / 2.10 m
      - Stern:      6.56 ft / 2.00 m
      - Average freeboard:   7.78 ft / 2.37 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 195.4 %
      - Above water (accommodation/working, high = better): 19.7 %
   Waterplane Area: 824 Square feet or 77 Square metres
   Displacement factor (Displacement / loading): 23 %
   Structure weight / hull surface area: 15 lbs/sq ft or 72 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.36
      - Longitudinal: 10.59
      - Overall: 0.50
   Hull space for machinery, storage, compartmentation is cramped
   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

[ctwaterman]

I am sure Iberia can get the tech at very reasonable rates from either Bavaria or Italy.   Just contact your local Curia arms dealer and.... ;)