Loa-class, Chilean Patrullero laid down 1944
This subchaser design originated in the United States and was purchased by the Chilean Navy for construction in the ASENAV shipyards of Valdivia. They will replace, in part or in whole, the aging
SC-1 subchaser class acquired from Atlantis. The class shares many similarities with the smaller
YDM-1 class minesweepers, but the
Loa-class incorporates more speed and a higher level of seakeeping. The ships will be named after Chilean rivers.
Displacement:
250 t light; 265 t standard; 313 t normal; 352 t full load
Dimensions: Length overall / water x beam x draught
178.14 ft / 175.00 ft x 23.00 ft x 6.90 ft (normal load)
54.30 m / 53.34 m x 7.01 m x 2.10 m
Armament:
1 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1944 Model
Dual purpose gun in deck mount
on centreline aft
2 - 1.57" / 40.0 mm guns (1x2 guns), 1.95lbs / 0.88kg shells, 1944 Model
Anti-aircraft guns in deck mount
on centreline forward
4 - 1.10" / 27.9 mm guns in single mounts, 0.67lbs / 0.30kg shells, 1944 Model
Anti-aircraft guns in deck mounts
on side, evenly spread
Weight of broadside 20 lbs / 9 kg
Shells per gun, main battery: 650
Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 1,996 shp / 1,489 Kw = 20.00 kts
Range 3,500nm at 15.00 kts
Bunker at max displacement = 87 tons
Complement:
36 - 48
Cost:
£0.121 million / $0.484 million
Distribution of weights at normal displacement:
Armament: 3 tons, 0.8 %
Machinery: 51 tons, 16.3 %
Hull, fittings & equipment: 146 tons, 46.7 %
Fuel, ammunition & stores: 63 tons, 20.3 %
Miscellaneous weights: 50 tons, 16.0 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
667 lbs / 303 Kg = 49.4 x 3.0 " / 76 mm shells or 0.6 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 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.08
Seaboat quality (Average = 1.00): 1.74
Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.394
Length to Beam Ratio: 7.61 : 1
'Natural speed' for length: 15.70 kts
Power going to wave formation at top speed: 61 %
Trim (Max stability = 0, Max steadiness = 100): 41
Bow angle (Positive = bow angles forward): 10.00 degrees
Stern overhang: 0.50 ft / 0.15 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 15.00 ft / 4.57 m
- Forecastle (25 %): 12.00 ft / 3.66 m
- Mid (50 %): 9.00 ft / 2.74 m
- Quarterdeck (15 %): 9.00 ft / 2.74 m
- Stern: 10.00 ft / 3.05 m
- Average freeboard: 10.50 ft / 3.20 m
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 79.6 %
- Above water (accommodation/working, high = better): 130.5 %
Waterplane Area: 2,563 Square feet or 238 Square metres
Displacement factor (Displacement / loading): 182 %
Structure weight / hull surface area: 29 lbs/sq ft or 142 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.82
- Longitudinal: 5.84
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
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
Breakdown of Miscellaneous Weights:
- 10 tons for Suite-42b electronics
- 8 tons for Kodkod antisubmarine rocket-launched depth charges
- 6 tons for depth charges (28x420-lb bombs)
- 16 tons for paravanes and other minesweeping equipment
- 10 tons other miscellaneous
50 tons total miscellaneous weight
Suite-42b Electronics:
- Type 103 "Nalca" navigational surface and air search radar (1 radar, 2 tons)
- SPR-42 Sound Projector-Receivers (5 tons)
- Roth-389b backup diesel generator set (3 tons)
Ships in Class:
-
Loa: Laid down at Valdivia January 1944, completed May 1944.
-
Maule: Laid down at Valdivia April 1944, completed August 1944.
-
Lauca: Laid down at Valdivia July 1944, completed November 1944.
-
Maipo: Laid down at Valdivia October 1944, completed February 1945.
-
Rapel: Laid down at Valdivia January 1945, completed May 1945.
-
Itata: Laid down at Valdivia April 1944, completed August 1945.
-
Pascua: Laid down at Valdivia July 1945, completed November 1945.
-
Tinguiririca: Laid down at Valdivia October 1945, completed February 1946.
-
Azopardo: Laid down at Valdivia January 1946, completed May 1946.
-
Cisnes: Laid down at Valdivia April 1946, completed August 1946.
-
Petrohué: Laid down at Valdivia July 1946, completed November 1946.
-
Colún: Laid down at Valdivia October 1946, completed February 1947.