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Repository for data pertaining to the subject vessels.

Colorado class - Rev A, Philippine Minesweeper laid down 1941

Displacement: 475 t light; 510 t standard; 633 t normal; 731 t full load

Dimensions: Length overall / water x beam x draught

198.56 ft / 191.93 ft x 25.26 ft x 7.87 ft (normal load) [60.52 m / 58.50 m x 7.70 m x 2.40 m]

Armament:

2 - 4.53" / 115 mm guns in single mounts, 46.40lbs / 21.05kg shells, 1941 Model Dual purpose guns in deck mounts
on centreline ends, evenly spread
2 - 1.38" / 35.0 mm guns (1x2 guns), 1.31lbs / 0.59kg shells, 1941 Model Anti-aircraft guns in deck mount on centreline aft, all raised guns - superfiring
4 - 0.59" / 15.0 mm guns (2x2 guns), 0.10lbs / 0.05kg shells, 1941 Model Anti-aircraft guns in deck mounts on side, evenly spread, all raised mounts
Weight of broadside 96 lbs / 43 kg
Shells per gun, main battery: 400

Armour:

Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.18" / 30 mm 0.59" / 15 mm -
2nd: 0.59" / 15 mm 0.39" / 10 mm -
3rd: 0.39" / 10 mm - -

Conning tower: 0.98" / 25 mm

Machinery:

Diesel Internal combustion motors, Geared drive, 2 shafts, 2,581 shp / 1,925 Kw = 18.00 kts
Range 8,800nm at 12.00 kts
Bunker at max displacement = 222 tons

Complement: 62 - 81

Cost: £0.224 million / $0.896 million

Distribution of weights at normal displacement:

Armament: 12 tons, 1.9 %
Armour: 8 tons, 1.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 6 tons, 1.0 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.2 %
Machinery: 68 tons, 10.8 %
Hull, fittings & equipment: 267 tons, 42.2 %
Fuel, ammunition & stores: 158 tons, 24.9 %
Miscellaneous weights: 120 tons, 19.0 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship): 1,224 lbs / 555 Kg = 26.4 x 4.5 " / 115 mm shells or 0.7 torpedoes
Stability (Unstable if below 1.00): 1.16
Metacentric height 0.8 ft / 0.3 m
Roll period: 11.6 seconds
Steadiness - As gun platform (Average = 50 %): 55 %
- Recoil effect (Restricted arc if above 1.00): 0.21
Seaboat quality (Average = 1.00): 1.58

Hull form characteristics: Hull has raised forecastle, rise forward of midbreak
Block coefficient: 0.580
Length to Beam Ratio: 7.60 : 1
'Natural speed' for length: 13.85 kts
Power going to wave formation at top speed: 60 %
Trim (Max stability = 0, Max steadiness = 100): 35
Bow angle (Positive = bow angles forward): 22.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 16.40 ft / 5.00 m
- Forecastle (20 %): 15.42 ft / 4.70 m (14.76 ft / 4.50 m aft of break)
- Mid (35 %): 14.76 ft / 4.50 m (8.20 ft / 2.50 m aft of break)
- Quarterdeck (35 %): 8.20 ft / 2.50 m
- Stern: 8.20 ft / 2.50 m
- Average freeboard: 10.71 ft / 3.26 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 73.3 %
- Above water (accommodation/working, high = better): 111.1 %
Waterplane Area: 3,480 Square feet or 323 Square metres
Displacement factor (Displacement / loading): 176 %
Structure weight / hull surface area: 42 lbs/sq ft or 207 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.05
- Longitudinal: 4.50
- Overall: 1.22
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is adequate
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Breakdown of miscellaneous weight

Sonar and A/S detection gear - 25 tons
Anti-submarine armament - DC racks for 24 DC and two K-guns - 20 tons
Minesweeping equipment - 50 tons
Tropicalization - 25 tons


Colorado – Laid down 1 January 1941; Launched 28 February 1941; Completed 25 May 1941
Pangasinan – Laid down 1 January 1941; Launched 28 February 1941; Completed 25 May 1941
Zambales – Laid down 1 April 1941; Launched 29 May 1941; Completed 23 August 1941
Vallejo – Laid down 1 April 1941; Launched 29 May 1941; Completed 23 August 1941
Cavite – Laid down 1 April 1941; Launched 29 May 1941; Completed 23 August 1941
Bataan – Laid down 1 April 1941; Launched 29 May 1941; Completed 23 August 1941
Isabela – Laid down 1 July 1941; Launched 28 August 1941; Completed 22 November 1941
Sierra – Laid down 1 July 1941; Launched 28 August 1941; Completed 22 November 1941

Eka Colorado class, Philippine Minesweeper laid down 1943

Displacement: 460 t light; 498 t standard; 646 t normal; 765 t full load

Dimensions: Length overall / water x beam x draught

198.56 ft / 191.93 ft x 25.92 ft x 7.87 ft (normal load) [60.52 m / 58.50 m x 7.90 m x 2.40 m]

Armament:

2 - 4.53" / 115 mm guns in single mounts, 46.40lbs / 21.05kg shells, 1943 Model Dual purpose guns in deck mounts on centreline ends, evenly spread
2 - 1.38" / 35.0 mm guns (1x2 guns), 1.31lbs / 0.59kg shells, 1943 Model Anti-aircraft guns in deck mount on centreline aft
4 - 0.59" / 15.0 mm guns (2x2 guns), 0.10lbs / 0.05kg shells, 1943 Model Anti-aircraft guns in deck mounts on side, evenly spread, all raised mounts
Weight of broadside 96 lbs / 43 kg
Shells per gun, main battery: 450

Armour:

Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.18" / 30 mm 0.59" / 15 mm -
2nd: 0.59" / 15 mm 0.39" / 10 mm -

Conning tower: 0.98" / 25 mm

Machinery:

Diesel Internal combustion motors, Geared drive, 2 shafts, 2,624 shp / 1,957 Kw = 18.00 kts
Range 8,600nm at 13.00 kts
Bunker at max displacement = 267 tons

Complement: 63 - 83

Cost: £0.233 million / $0.934 million

Distribution of weights at normal displacement:

Armament: 12 tons, 1.9 %
Armour: 8 tons, 1.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 6 tons, 1.0 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.2 %
Machinery: 68 tons, 10.5 %
Hull, fittings & equipment: 233 tons, 36.0 %
Fuel, ammunition & stores: 186 tons, 28.8 %
Miscellaneous weights: 140 tons, 21.7 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship): 1,258 lbs / 571 Kg = 27.1 x 4.5 " / 115 mm shells or 0.7 torpedoes
Stability (Unstable if below 1.00): 1.16
Metacentric height 0.9 ft / 0.3 m
Roll period: 11.6 seconds
Steadiness - As gun platform (Average = 50 %): 66 %
- Recoil effect (Restricted arc if above 1.00): 0.21
Seaboat quality (Average = 1.00): 1.82

Hull form characteristics:

Hull has a flush deck
Block coefficient: 0.577
Length to Beam Ratio: 7.41 : 1
'Natural speed' for length: 13.85 kts
Power going to wave formation at top speed: 60 %
Trim (Max stability = 0, Max steadiness = 100): 36
Bow angle (Positive = bow angles forward): 22.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 16.40 ft / 5.00 m
- Forecastle (20 %): 14.76 ft / 4.50 m
- Mid (35 %): 10.17 ft / 3.10 m
- Quarterdeck (35 %): 10.17 ft / 3.10 m
- Stern: 10.17 ft / 3.10 m
- Average freeboard: 11.56 ft / 3.53 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 75.3 %
- Above water (accommodation/working, high = better): 117.8 %
Waterplane Area: 3,562 Square feet or 331 Square metres
Displacement factor (Displacement / loading): 170 %
Structure weight / hull surface area: 35 lbs/sq ft or 170 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.85
- Longitudinal: 4.54
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is adequate
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Breakdown of miscellaneous weight

Sonar and A/S detection gear - 25 tons
Air and surface warning radar - 20 tons
Anti-submarine armament - DC racks for 24 DC and two K-guns - 20 tons
Minesweeping equipment - 50 tons
Tropicalization - 25 tons


Batanes – Laid down 1 January 1943; Launched 17 March 1943; Completed 15 May 1943
La Union – Laid down 1 January 1943; Launched 17 March 1943; Completed 15 May 1943
Nueva Ecija - Laid down 1 April 1943; Launched 15 June 1943; Completed 13 August 1943
Kudarat - Laid down 1 April 1943; Launched 15 June 1943; Completed 13 August 1943
Nueva Vizcaya - Laid down 1 July 1943; Launched 14 September 1943; Completed 12 November 1943
Compostela - Laid down 1 July 1943; Launched 14 September 1943; Completed 12 November 1943
Camarines - Laid down 1 October 1943; Launched 15 December 1943; Completed 12 February 1944
Romblon - Laid down 1 October 1943; Launched 15 December 1943; Completed 12 February 1944