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Descubierta class Antisubmarine Gunboat

Descubierta, Philippine Antisubmarine Gunboat laid down 1948

Displacement: 498 t light; 534 t standard; 605 t normal; 662 t full load

Dimensions: Length overall / water x beam x draught

236.90 ft / 229.66 ft x 24.93 ft x 7.38 ft (normal load) [72.21 m / 70.00 m x 7.60 m x 2.25 m]

Armament:

4 - 2.24" / 57.0 mm guns (2x2 guns), 5.65lbs / 2.56kg shells, 1948 Model Anti-aircraft guns in deck mounts on centreline ends, evenly spread, 1 raised mount
8 - 0.59" / 15.0 mm guns (4x2 guns), 0.10lbs / 0.05kg shells, 1948 Model Anti-aircraft guns in deck mounts on side, all amidships
Weight of broadside 23 lbs / 11 kg
Shells per gun, main battery: 1,800

Armour:

Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.98" / 25 mm 0.59" / 15 mm -
2nd: 0.39" / 10 mm - -

Conning tower: 0.98" / 25 mm

Machinery:

Diesel Internal combustion motors, Geared drive, 3 shafts, 8,340 shp / 6,222 Kw = 26.00 kts
Range 4,200nm at 14.00 kts
Bunker at max displacement = 127 tons

Complement: 60 - 79

Cost: £0.361 million / $1.443 million

Distribution of weights at normal displacement:

Armament: 3 tons, 0.5 %
Armour: 6 tons, 0.9 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 4 tons, 0.7 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.3 %
Machinery: 204 tons, 33.7 %
Hull, fittings & equipment: 215 tons, 35.6 %
Fuel, ammunition & stores: 108 tons, 17.8 %
Miscellaneous weights: 70 tons, 11.6 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship): 457 lbs / 207 Kg = 80.8 x 2.2 " / 57 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.15
Metacentric height 0.8 ft / 0.2 m
Roll period: 11.7 seconds
Steadiness - As gun platform (Average = 50 %): 64 %
- Recoil effect (Restricted arc if above 1.00): 0.08
Seaboat quality (Average = 1.00): 1.33

Hull form characteristics:

Hull has a flush deck and transom stern
Block coefficient: 0.501
Length to Beam Ratio: 9.21: 1
'Natural speed' for length: 17.40 kts
Power going to wave formation at top speed: 68 %
Trim (Max stability = 0, Max steadiness = 100): 48
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 1.64 ft / 0.50 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 17.22 ft / 5.25 m
- Forecastle (25 %): 17.22 ft / 5.25 m
- Mid (50 %): 10.66 ft / 3.25 m
- Quarterdeck (25 %): 10.66 ft / 3.25 m
- Stern: 10.66 ft / 3.25 m
- Average freeboard: 13.12 ft / 4.00 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 129.6 %
- Above water (accommodation/working, high = better): 155.1 %
Waterplane Area: 3,971 Square feet or 369 Square metres
Displacement factor (Displacement / loading): 119 %
Structure weight / hull surface area: 25 lbs/sq ft or 122 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.58
- Longitudinal: 4.51
- Overall: 0.72
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is excellent
Good seaboat, rides out heavy weather easily

Breakdown of Miscellaneous Weight

Radar and electronics suite - 10 tons
Sonar and A/S sensor suite - 10 tons
Ahead-thrown ASW weapon installation - 10 tons
Depth charge racks and mortars - 30 tons (comprises four K-guns @2.5 tons per and two depth charge racks at 10 tons per inclusive of reloads)
Tropicalization - 10 tons

Looks good, cheap simple and effective.
I assume your doctrine at this point is mass? I.e. many boats to saturate a submarine contact with depth-charges and pattern-charges/rockets?

Quoted

I assume your doctrine at this point is mass? I.e. many boats to saturate a submarine contact with depth-charges and pattern-charges/rockets?

I would say that it is about building them quickly as well. It takes a bit more than 11 months to build one of those Long Range Chinese Submarines while it only takes 5 months to build one Descubierta class vessel.

Alcotan, Philippine Coastal Escort laid down 1948

Displacement: 590 t light; 622 t standard; 750 t normal; 853 t full load

Dimensions: Length overall / water x beam x draught

258.49 ft / 249.34 ft x 24.93 ft x 7.55 ft (normal load) [78.79 m / 76.00 m x 7.60 m x 2.30 m]

Armament:

4 - 2.95" / 75.0 mm guns (2x2 guns), 12.87lbs / 5.84kg shells, 1948 Model Anti-aircraft guns in deck mounts on centreline ends, evenly spread, 1 raised mount
8 - 0.98" / 25.0 mm guns (4x2 guns), 0.48lbs / 0.22kg shells, 1948 Model Anti-aircraft guns in deck mounts on side, all amidships
Weight of broadside 55 lbs / 25 kg
Shells per gun, main battery: 500

Armour:

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

Conning tower: 0.98" / 25 mm

Machinery:

Diesel Internal combustion motors, Geared drive, 2 shafts, 8,056 shp / 6,010 Kw = 25.00 kts
Range 4,800nm at 16.00 kts
Bunker at max displacement = 231 tons

Complement: 71 - 93

Cost: £0.403 million / $1.611 million

Distribution of weights at normal displacement:

Armament: 7 tons, 0.9 %
Armour: 6 tons, 0.8 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 4 tons, 0.6 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.2 %
Machinery: 197 tons, 26.2 %
Hull, fittings & equipment: 291 tons, 38.7 %
Fuel, ammunition & stores: 160 tons, 21.3 %
Miscellaneous weights: 90 tons, 12.0 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship): 949 lbs / 431 Kg = 73.8 x 3.0 " / 75 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.15
Metacentric height 0.8 ft / 0.2 m
Roll period: 11.6 seconds
Steadiness - As gun platform (Average = 50 %): 63 %
- Recoil effect (Restricted arc if above 1.00): 0.19
Seaboat quality (Average = 1.00): 1.66

Hull form characteristics:

Hull has rise forward of midbreak and transom stern
Block coefficient: 0.560
Length to Beam Ratio: 10.00: 1
'Natural speed' for length: 17.91 kts
Power going to wave formation at top speed: 65 %
Trim (Max stability = 0, Max steadiness = 100): 38
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 18.04 ft / 5.50 m
- Forecastle (20 %): 18.04 ft / 5.50 m
- Mid (50 %): 18.04 ft / 5.50 m (9.84 ft / 3.00 m aft of break)
- Quarterdeck (25 %): 9.84 ft / 3.00 m
- Stern: 9.84 ft / 3.00 m
- Average freeboard: 13.94 ft / 4.25 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 107.3 %
- Above water (accommodation/working, high = better): 175.1 %
Waterplane Area: 4,559 Square feet or 424 Square metres
Displacement factor (Displacement / loading): 138 %
Structure weight / hull surface area: 28 lbs/sq ft or 139 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.63
- Longitudinal: 5.05
- Overall: 0.78
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is excellent
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Breakdown of Miscellaneous Weight

Radar an electronics suite - 10 tons
Sonar and A/S sensor suite - 15 tons
Ahead-thrown ASW weapon installation - 15 tons
Depth charge racks and mortars - 40 tons (comprises four K-guns @2.5 tons per and two depth charge racks at 15 tons per inclusive of reloads
Tropicalization - 10 tons