Iberia TB Designs of the 1920's

[miketr]

I agree. But 75 mm on MTB, is it possible ?

Things like a MTB / PT-Boat / Schnellboot I view as a type of MAS boat.  The German S boats were the biggest and they were under 100 tons.  My ships are over 2 to 3 times larger in size.

Michael 

[The Rock Doctor]

I don't think the extra tonnage gets you much more value.

[ctwaterman]

I don't think the extra tonnage gets you much more value.

What he said I went with 200 tons because my 250 ton design didnt work.  SS and I have this Hate - Hate relationship....

If the 250 Tons gets you a relatively fast ship once you plug it into the Speed adjuster program and its got the gun and torps you want go with the smaller one in larger numbers.

As for all these small automatic weapons on ships.  They are what pilots call pre-emptive revenge weapons by the time a plane is in range of a 13mm Machine gun or even a 20mm cannon its already or is just about to drop its torpedo only heavy weapons like 3" and 5" guns can destroy them at range and we dont the fire control to reliabely do that yet or the Fuzes.

Heavy Automatic weapons like the 40mm are in the mid range they have a very short period of time to engage the plane before it drops its torp and they also lack a very accurate fuze for exploding so the too require a direct hit in this time period.

[Jefgte]

I agree with Rocky, 4x250t is better than 3x334t ... with the same armament.

You could install the 2x40 mount from NUS (see CTBM200) in place of the 75mm AA. Better in ROF & vs MTBs

The price is : free


Jef  ;)

[damocles]

I agree with Rocky, 4x250t is better than 3x334t ... with the same armament.

You could install the 2x40 mount from NUS (see CTBM200) in place of the 75mm AA. Better in ROF & vs MTBs

The price is : free


Jef  ;)

Exactly why all those 15 mm machine guns I use. I don't have 1925 AAA fire control. and the 75 mm  AAA I have with 1915 fire control is a Zeppelin gun.

Maybe we can talk?

D.

[Jefgte]

That depend also, Mike, the work of the ship  ???
Coastal patrol, harbor defense... = economical TB

or Small (70m) max TB abble to work in a squadron in a coastal battle (Archipel)...

Exactly why all those 15 mm machine guns I use. I don't have 1925 AAA fire control. and the 75 mm  AAA I have with 1915 fire control is a Zeppelin gun.

Maybe we can talk?

The NUS 40mm/50 mlle 1916 is just a small 75° angle gun with a fast ROF (30 max) - "HA/QF" - abble to engage Zeppelin, aircraft, TBs & MTBs
M1 & M2 - they have not fire control system.


Jef  ;)

[miketr]

Mission:  Iberia has a number of places where something larger than a MAS boat could be useful. 

Straits of Gibraltar, Puerto Rico, Philippines, Greece and coast defense work in general.  They are sea denial ships intended to make it expensive for larger ships to operate in congested waters.

[miketr]

I made some changes to the design.  I removed the 105 for 75 and swapped out the 75 AA for a 40 AA.  I cut the number of torpedo tubes down from four to two.  The freed displacement went to additional range.

TB-1920-S-250 A, Iberia Torpedo Boat laid down 1920 (Engine 1916)

Displacement:
   250 t light; 258 t standard; 299 t normal; 332 t full load

Dimensions: Length overall / water x beam x draught
   223.10 ft / 223.10 ft x 18.70 ft x 5.91 ft (normal load)
   68.00 m / 68.00 m x 5.70 m  x 1.80 m

Armament:
      1 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1920 Model
     Quick firing gun in deck mount
     on centreline forward
      1 - 1.57" / 40.0 mm guns in single mounts, 1.95lbs / 0.89kg shells, 1920 Model
     Anti-aircraft gun in deck mount
     on centreline aft, 1 raised gun
      2 - 0.49" / 12.5 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1920 Model
     Breech loading guns in deck mounts
     on side, evenly spread, all raised mounts
   Weight of broadside 15 lbs / 7 kg
   Shells per gun, main battery: 130
   2 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.79" / 20 mm         -               -

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 2 shafts, 10,001 shp / 7,461 Kw = 29.41 kts
   Range 270nm at 29.40 kts
   Bunker at max displacement = 75 tons

Complement:
   35 - 46

Cost:
   £0.078 million / $0.312 million

Distribution of weights at normal displacement:
   Armament: 2 tons, 0.6 %
   Armour: 1 tons, 0.4 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 1 tons, 0.4 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 162 tons, 54.2 %
   Hull, fittings & equipment: 76 tons, 25.5 %
   Fuel, ammunition & stores: 49 tons, 16.3 %
   Miscellaneous weights: 9 tons, 3.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     69 lbs / 31 Kg = 5.3 x 3.0 " / 75 mm shells or 0.1 torpedoes
   Stability (Unstable if below 1.00): 1.28
   Metacentric height 0.6 ft / 0.2 m
   Roll period: 9.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 42 %
         - Recoil effect (Restricted arc if above 1.00): 0.05
   Seaboat quality  (Average = 1.00): 0.44

Hull form characteristics:
   Hull has rise forward of midbreak
   Block coefficient: 0.425
   Length to Beam Ratio: 11.93 : 1
   'Natural speed' for length: 14.94 kts
   Power going to wave formation at top speed: 69 %
   Trim (Max stability = 0, Max steadiness = 100): 81
   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 %):   9.02 ft / 2.75 m
      - Mid (50 %):      7.87 ft / 2.40 m (4.59 ft / 1.40 m aft of break)
      - Quarterdeck (15 %):   4.59 ft / 1.40 m
      - Stern:      4.59 ft / 1.40 m
      - Average freeboard:   6.73 ft / 2.05 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 182.9 %
      - Above water (accommodation/working, high = better): 60.6 %
   Waterplane Area: 2,610 Square feet or 243 Square metres
   Displacement factor (Displacement / loading): 39 %
   Structure weight / hull surface area: 17 lbs/sq ft or 85 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.50
      - Longitudinal: 0.74
      - Overall: 0.52
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped
   Caution: Lacks seaworthiness - very limited seakeeping ability

Two 21" (2 t) Torpedos (2 x 2) 4 tons
15 Depth Charges 5 tons


Trial Speed: 33.92

Range
29.4 knots = 270 nm (9 hours)
25 knots = 460 nm
20 knots = 910 nm
15 knots = 2000 nm

[maddox]

Nasty customer..

[miketr]

I think they will do the job.