A small torpedobooten for use in the Ost Afrika/Rift Sea area. Intent is to deliver torpedoes, not get in gun fights, therefore the 88mm guns and the 6 50cm TTs.
A-1, Brandenburg Torpedobooten laid down 1916
Displacement:
610 t light; 629 t standard; 690 t normal; 739 t full load
Dimensions: Length overall / water x beam x draught
242.78 ft / 234.58 ft x 24.93 ft x 9.84 ft (normal load)
74.00 m / 71.50 m x 7.60 m x 3.00 m
Armament:
2 - 3.46" / 88.0 mm guns in single mounts, 22.05lbs / 10.00kg shells, 1908 Model
Quick firing guns in deck mounts
on centreline ends, evenly spread, 1 raised mount
4 - 0.30" / 7.7 mm guns in single mounts, 0.01lbs / 0.01kg shells, 1916 Model
Machine guns in deck mounts
on side ends, evenly spread
Weight of broadside 44 lbs / 20 kg
Shells per gun, main battery: 200
6 - 19.7" / 500 mm above water torpedoes
Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 17,749 shp / 13,241 Kw = 29.60 kts
Range 3,000nm at 12.00 kts
Bunker at max displacement = 110 tons
Complement:
66 - 87
Cost:
£0.125 million / $0.502 million
Distribution of weights at normal displacement:
Armament: 5 tons, 0.8 %
Machinery: 364 tons, 52.7 %
Hull, fittings & equipment: 225 tons, 32.6 %
Fuel, ammunition & stores: 80 tons, 11.6 %
Miscellaneous weights: 16 tons, 2.3 %
-10t Small Markoni Installation
-6t Torpedoes
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
205 lbs / 93 Kg = 9.9 x 3.5 " / 88 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 0.8 ft / 0.2 m
Roll period: 12.0 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.15
Seaboat quality (Average = 1.00): 1.10
Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.419
Length to Beam Ratio: 9.41 : 1
'Natural speed' for length: 15.32 kts
Power going to wave formation at top speed: 72 %
Trim (Max stability = 0, Max steadiness = 100): 63
Bow angle (Positive = bow angles forward): 16.70 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 16.40 ft / 5.00 m
- Forecastle (20 %): 16.01 ft / 4.88 m
- Mid (30 %): 16.01 ft / 4.88 m (12.01 ft / 3.66 m aft of break)
- Quarterdeck (15 %): 12.01 ft / 3.66 m
- Stern: 12.01 ft / 3.66 m
- Average freeboard: 13.24 ft / 4.04 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 178.8 %
- Above water (accommodation/working, high = better): 50.3 %
Waterplane Area: 3,645 Square feet or 339 Square metres
Displacement factor (Displacement / loading): 50 %
Structure weight / hull surface area: 25 lbs/sq ft or 123 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 4.80
- Overall: 0.62
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Ship has slow, easy roll, a good, steady gun platform
Bear in mind that you don't need to leave room for short-range wireless any more.
If you reduced the width until you get a 10:1 L:W ratio - would you lose much performance?
The question is, do you need a torpedo heavy DD in the Rift? What is to be her role?
Quote from: The Rock Doctor on January 04, 2009, 06:29:06 PM
Bear in mind that you don't need to leave room for short-range wireless any more.
If you reduced the width until you get a 10:1 L:W ratio - would you lose much performance?
Same weight, better seakeeping (1.13 v 1.10) but less steadiness (63 v 70) w/ same stability 1.10
Quote from: Desertfox on January 04, 2009, 06:48:03 PM
The question is, do you need a torpedo heavy DD in the Rift? What is to be her role?
To make Orange Juice?
I fiddled w/ it a little:
A-1, Brandenburg Torpedobooten laid down 1916
Displacement:
580 t light; 598 t standard; 656 t normal; 702 t full load
Dimensions: Length overall / water x beam x draught
242.78 ft / 234.58 ft x 23.46 ft x 9.84 ft (normal load)
74.00 m / 71.50 m x 7.15 m x 3.00 m
Armament:
2 - 3.46" / 88.0 mm guns in single mounts, 22.05lbs / 10.00kg shells, 1908 Model
Quick firing guns in deck mounts
on centreline ends, evenly spread, 1 raised mount
4 - 0.30" / 7.7 mm guns in single mounts, 0.01lbs / 0.00kg shells, 1916 Model
Machine guns in deck mounts
on side ends, evenly spread
Weight of broadside 44 lbs / 20 kg
Shells per gun, main battery: 200
6 - 19.7" / 500 mm above water torpedoes
Machinery:
Oil fired boilers, steam turbines,
Direct drive, 2 shafts, 17,050 shp / 12,719 Kw = 29.60 kts
Range 2,900nm at 12.00 kts
Bunker at max displacement = 104 tons
Complement:
64 - 84
Cost:
£0.120 million / $0.479 million
Distribution of weights at normal displacement:
Armament: 5 tons, 0.8 %
Machinery: 346 tons, 52.8 %
Hull, fittings & equipment: 223 tons, 33.9 %
Fuel, ammunition & stores: 76 tons, 11.6 %
Miscellaneous weights: 6 tons, 0.9 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
198 lbs / 90 Kg = 9.5 x 3.5 " / 88 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.10
Metacentric height 0.7 ft / 0.2 m
Roll period: 11.9 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.19
Seaboat quality (Average = 1.00): 1.20
Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.424
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 15.32 kts
Power going to wave formation at top speed: 71 %
Trim (Max stability = 0, Max steadiness = 100): 58
Bow angle (Positive = bow angles forward): 16.70 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 16.40 ft / 5.00 m
- Forecastle (20 %): 16.01 ft / 4.88 m
- Mid (30 %): 16.01 ft / 4.88 m (12.01 ft / 3.66 m aft of break)
- Quarterdeck (15 %): 12.01 ft / 3.66 m
- Stern: 12.01 ft / 3.66 m
- Average freeboard: 13.24 ft / 4.04 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 177.9 %
- Above water (accommodation/working, high = better): 43.9 %
Waterplane Area: 3,440 Square feet or 320 Square metres
Displacement factor (Displacement / loading): 50 %
Structure weight / hull surface area: 25 lbs/sq ft or 120 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 5.43
- Overall: 0.63
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is extremely poor
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily
Quote from: Sachmle on January 04, 2009, 06:56:18 PM
I fiddled w/ it a little:
A-1, Brandenburg Torpedobooten laid down 1916
Displacement:
580 t light; 598 t standard; 656 t normal; 702 t full load
I think you give up far too much performance to get the seakeeping number. You can get 30kts and marginally better range on a 300ton ship if you are willing to accept a seakeeping below 0,8. It should not be a problem considering the mission profile I think.
I would also reduce the number of torpedoes to 3-4, if the ship does not hit with the first attack, it is unlikely it will be able to get into a position for a 2nd in any case.
I agree with the first point. I'd assume you're just going to fire off all six fish in one go, however.
Quote from: The Rock Doctor on January 05, 2009, 06:52:36 AM
I agree with the first point. I'd assume you're just going to fire off all six fish in one go, however.
Two fixed tubes over the bow fired on the way in, two twin sets amidships to fire as she turns.