WesWorld

Modified from pic by The Rock Doctor

Usumacinta class, Mexico Landing Ship Assault laid down 1919 (Engine 1924)

Displacement:
7,940 t light; 8,158 t standard; 9,487 t normal; 10,550 t full load

Dimensions: Length overall / water x beam x draught
500.00 ft / 500.00 ft x 70.00 ft x 17.90 ft (normal load)
152.40 m / 152.40 m x 21.34 m x 5.46 m

Armament:
2 - 5.00" / 127 mm guns (1x2 guns), 62.50lbs / 28.35kg shells, 1933 Model
Dual purpose guns in a deck mount with hoist
on centreline forward
8 - 1.85" / 47.0 mm guns (4x2 guns), 3.17lbs / 1.44kg shells, 1933 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
20 - 0.50" / 12.7 mm guns (10x2 guns), 0.06lbs / 0.03kg shells, 1933 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 152 lbs / 69 kg
Shells per gun, main battery: 300

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Ends: Unarmoured
Upper: 0.50" / 13 mm 100.00 ft / 30.48 m 10.00 ft / 3.05 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.00" / 25 mm - -
2nd: 0.50" / 13 mm - -

- Conning tower: 1.00" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 2 shafts, 14,748 shp / 11,002 Kw = 20.00 kts
Range 10,000nm at 15.00 kts
Bunker at max displacement = 2,392 tons

Complement:
479 - 624

Cost:
£0.789 million / $3.158 million

Distribution of weights at normal displacement:
Armament: 19 tons, 0.2 %
Armour: 46 tons, 0.5 %
- Belts: 31 tons, 0.3 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 6 tons, 0.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 10 tons, 0.1 %
Machinery: 486 tons, 5.1 %
Hull, fittings & equipment: 3,689 tons, 38.9 %
Fuel, ammunition & stores: 1,547 tons, 16.3 %
Miscellaneous weights: 3,700 tons, 39.0 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
23,444 lbs / 10,634 Kg = 375.1 x 5.0 " / 127 mm shells or 3.1 torpedoes
Stability (Unstable if below 1.00): 1.07
Metacentric height 3.3 ft / 1.0 m
Roll period: 16.1 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.04
Seaboat quality (Average = 1.00): 2.00

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.530
Length to Beam Ratio: 7.14 : 1
'Natural speed' for length: 22.36 kts
Power going to wave formation at top speed: 40 %
Trim (Max stability = 0, Max steadiness = 100): 35
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: 37.00 ft / 11.28 m
- Forecastle (20 %): 27.00 ft / 8.23 m
- Mid (50 %): 27.00 ft / 8.23 m
- Quarterdeck (15 %): 27.00 ft / 8.23 m
- Stern: 20.00 ft / 6.10 m
- Average freeboard: 27.28 ft / 8.31 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 61.6 %
- Above water (accommodation/working, high = better): 257.4 %
Waterplane Area: 23,974 Square feet or 2,227 Square metres
Displacement factor (Displacement / loading): 195 %
Structure weight / hull surface area: 92 lbs/sq ft or 450 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.95
- Longitudinal: 3.27
- Overall: 1.07
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

Miscellaneous Weight:
-2000 t for troop accommodation (= 1000 troops)
-200 t for cargo
-200 t for medical and training facilities
-200 t for strengthening
-500 t for 10 x LCI
-500 t for heavy duty davits
-100 t for 3 aircraft