Here is a Mexican Patrol Boat, probably the first ship to be laid down. 16 planned.
Sonora, Mexico Patrol Boat laid down 1930
Displacement:
489 t light; 507 t standard; 608 t normal; 688 t full load
Dimensions: Length overall / water x beam x draught
250.00 ft / 250.00 ft x 27.00 ft x 7.00 ft (normal load)
76.20 m / 76.20 m x 8.23 m x 2.13 m
Armament:
1 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1930 Model
Breech loading gun in deck mount
on centreline forward
2 - 1.85" / 47.0 mm guns in single mounts, 3.17lbs / 1.44kg shells, 1930 Model
Dual purpose guns in deck mounts
on centreline, all aft
Weight of broadside 69 lbs / 31 kg
Shells per gun, main battery: 150
4 - 21.0" / 533.4 mm above water torpedoes
Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm - -
Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 7,850 shp / 5,856 Kw = 25.00 kts
Range 4,000nm at 15.00 kts
Bunker at max displacement = 181 tons
Complement:
60 - 79
Cost:
£0.241 million / $0.964 million
Distribution of weights at normal displacement:
Armament: 9 tons, 1.4 %
Armour: 3 tons, 0.5 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 3 tons, 0.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 238 tons, 39.2 %
Hull, fittings & equipment: 224 tons, 36.9 %
Fuel, ammunition & stores: 119 tons, 19.6 %
Miscellaneous weights: 15 tons, 2.5 %
Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
431 lbs / 196 Kg = 6.9 x 5.0 " / 127 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.34
Metacentric height 1.2 ft / 0.4 m
Roll period: 10.5 seconds
Steadiness - As gun platform (Average = 50 %): 69 %
- Recoil effect (Restricted arc if above 1.00): 0.12
Seaboat quality (Average = 1.00): 1.19
Hull form characteristics:
Hull has low forecastle
Block coefficient: 0.450
Length to Beam Ratio: 9.26 : 1
'Natural speed' for length: 15.81 kts
Power going to wave formation at top speed: 62 %
Trim (Max stability = 0, Max steadiness = 100): 58
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 15.00 ft / 4.57 m
- Forecastle (20 %): 10.00 ft / 3.05 m (11.00 ft / 3.35 m aft of break)
- Mid (50 %): 11.00 ft / 3.35 m
- Quarterdeck (15 %): 11.00 ft / 3.35 m
- Stern: 11.00 ft / 3.35 m
- Average freeboard: 11.20 ft / 3.41 m
Ship tends to be wet forward
Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 140.4 %
- Above water (accommodation/working, high = better): 89.0 %
Waterplane Area: 4,306 Square feet or 400 Square metres
Displacement factor (Displacement / loading): 108 %
Structure weight / hull surface area: 29 lbs/sq ft or 142 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.67
- Longitudinal: 2.20
- Overall: 0.75
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped