WesWorld

A possible deep-water ASW escort for the Kriegsmarine.


F-7, German Escort laid down 1937

Displacement:
870 t light; 912 t standard; 1,093 t normal; 1,239 t full load

Dimensions: Length overall / water x beam x draught
291.40 ft / 278.87 ft x 27.89 ft x 9.84 ft (normal load)
88.82 m / 85.00 m x 8.50 m x 3.00 m

Armament:
4 - 4.13" / 105 mm guns (2x2 guns), 35.32lbs / 16.02kg shells, 1928 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread
2 - 1.46" / 37.0 mm guns (1x2 guns), 1.55lbs / 0.70kg shells, 1937 Model
Anti-aircraft guns in deck mount
on centreline forward, all raised guns - superfiring
8 - 0.79" / 20.0 mm guns (4x2 guns), 0.24lbs / 0.11kg shells, 1937 Model
Anti-aircraft guns in deck mounts
on side, all amidships, 2 raised mounts - superfiring
Weight of broadside 146 lbs / 66 kg
Shells per gun, main battery: 240

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.18" / 30 mm 0.79" / 20 mm -
2nd: 0.79" / 20 mm 0.79" / 20 mm -
3rd: 0.39" / 10 mm - -

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 9,326 shp / 6,957 Kw = 25.00 kts
Range 6,000nm at 15.00 kts
Bunker at max displacement = 328 tons

Complement:
94 - 123

Cost:
£0.447 million / $1.789 million

Distribution of weights at normal displacement:
Armament: 18 tons, 1.7 %
Armour: 12 tons, 1.1 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 12 tons, 1.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 258 tons, 23.6 %
Hull, fittings & equipment: 471 tons, 43.1 %
Fuel, ammunition & stores: 224 tons, 20.5 %
Miscellaneous weights: 110 tons, 10.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,595 lbs / 723 Kg = 45.2 x 4.1 " / 105 mm shells or 0.6 torpedoes
Stability (Unstable if below 1.00): 1.13
Metacentric height 0.9 ft / 0.3 m
Roll period: 12.2 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.28
Seaboat quality (Average = 1.00): 1.56

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.500
Length to Beam Ratio: 10.00 : 1
'Natural speed' for length: 19.06 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 45
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 18.86 ft / 5.75 m
- Forecastle (20 %): 17.22 ft / 5.25 m
- Mid (50 %): 16.40 ft / 5.00 m (9.84 ft / 3.00 m aft of break)
- Quarterdeck (15 %): 9.84 ft / 3.00 m
- Stern: 9.84 ft / 3.00 m
- Average freeboard: 13.54 ft / 4.13 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 101.6 %
- Above water (accommodation/working, high = better): 142.6 %
Waterplane Area: 5,388 Square feet or 501 Square metres
Displacement factor (Displacement / loading): 139 %
Structure weight / hull surface area: 42 lbs/sq ft or 207 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.87
- Longitudinal: 4.11
- Overall: 1.01
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

20 tons reserved for sonar

20 tons reserved for depth charges and rails

30 tons reserved for Fi-228 Kolibri helicopter

40 tons reserved for growth

Same comments as usual - too much armament on the hull will restrict it's main function. There's little point in that amount of armament anyway.

Landing a helicopter on something that small is probably a bit optimistic in a seaway. The space would be far better used for boats or AS weapons.

It's roughly based on this historical design: http://www.german-navy.de/kriegsmarine/s…t1941/tech.html. I shrank the dimensions a LITTLE, but not much, and historically this ship http://www.german-navy.de/kriegsmarine/s…ache/index.html was operating F1-282s in the the Med. Fl-282s were also operated off a turret-top platform on one of the CLs in the Baltic, they're aren't very big.

A future plan is for the 37mm mounting to be replaced with some sort of ahead thrown weapon, once the need for such a thing becomes clear. That won't happen until wartime, though, since that's what prompted the development historically.

Historical ASW vessels operating between the US and Great Britain didn't have to worry too much about air attack (being spotted by Fw-200s or Ju-290s is a different problem), a German ASW escort is very likely to be having to operate (at least on one portion of it's journey) in areas where the air isn't ALWAYS friendly.

Here's a slightly larger version of the vessel:

F-7, German Escort laid down 1937

Displacement:
1,097 t light; 1,144 t standard; 1,351 t normal; 1,516 t full load

Dimensions: Length overall / water x beam x draught
291.88 ft / 278.87 ft x 34.45 ft x 9.84 ft (normal load)
88.96 m / 85.00 m x 10.50 m x 3.00 m

Armament:
4 - 4.13" / 105 mm guns (2x2 guns), 35.32lbs / 16.02kg shells, 1928 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread
2 - 1.46" / 37.0 mm guns (1x2 guns), 1.55lbs / 0.70kg shells, 1937 Model
Anti-aircraft guns in deck mount
on centreline forward, all raised guns - superfiring
8 - 0.79" / 20.0 mm guns (4x2 guns), 0.24lbs / 0.11kg shells, 1937 Model
Anti-aircraft guns in deck mounts
on side, all amidships, 2 raised mounts - superfiring
Weight of broadside 146 lbs / 66 kg
Shells per gun, main battery: 240

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.18" / 30 mm 0.79" / 20 mm -
2nd: 0.79" / 20 mm 0.79" / 20 mm -
3rd: 0.39" / 10 mm - -

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 10,767 shp / 8,032 Kw = 25.00 kts
Range 6,000nm at 15.00 kts
Bunker at max displacement = 372 tons

Complement:
110 - 144

Cost:
£0.521 million / $2.085 million

Distribution of weights at normal displacement:
Armament: 18 tons, 1.4 %
Armour: 12 tons, 0.9 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 12 tons, 0.9 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 298 tons, 22.1 %
Hull, fittings & equipment: 609 tons, 45.1 %
Fuel, ammunition & stores: 254 tons, 18.8 %
Miscellaneous weights: 160 tons, 11.8 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
2,479 lbs / 1,124 Kg = 70.2 x 4.1 " / 105 mm shells or 0.8 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 1.2 ft / 0.4 m
Roll period: 13.0 seconds
Steadiness - As gun platform (Average = 50 %): 73 %
- Recoil effect (Restricted arc if above 1.00): 0.18
Seaboat quality (Average = 1.00): 1.52

Hull form characteristics:
Hull has rise forward of midbreak
and transom stern
Block coefficient: 0.500
Length to Beam Ratio: 8.10 : 1
'Natural speed' for length: 19.39 kts
Power going to wave formation at top speed: 64 %
Trim (Max stability = 0, Max steadiness = 100): 48
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19.69 ft / 6.00 m
- Forecastle (20 %): 17.22 ft / 5.25 m
- Mid (80 %): 17.22 ft / 5.25 m (9.84 ft / 3.00 m aft of break)
- Quarterdeck (15 %): 9.84 ft / 3.00 m
- Stern: 9.84 ft / 3.00 m
- Average freeboard: 15.94 ft / 4.86 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 96.0 %
- Above water (accommodation/working, high = better): 192.0 %
Waterplane Area: 6,656 Square feet or 618 Square metres
Displacement factor (Displacement / loading): 148 %
Structure weight / hull surface area: 48 lbs/sq ft or 234 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.83
- Longitudinal: 5.04
- Overall: 1.00
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

20 tons reserved for sonar

10 tons reserved for radar

40 tons reserved for depth charges, launchers, and rails

30 tons reserved for Fi-228 Kolibri helicopter

60 tons reserved for growth