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Up until 1938, the USN had no dedicated landing ships or landing craft, instead using cargo and passenger ships and boats to land troops ashore when necessary. Beginning in 1938, however, the USN began laying down vessels specifically designed for the purpose of landing troops ashore.

Landing Ship, Tank, United States LST laid down 1938

Displacement:
1,789 t light; 1,834 t standard; 2,023 t normal; 2,175 t full load

Dimensions: Length overall / water x beam x draught
330.01 ft / 328.00 ft x 50.00 ft x 5.50 ft (normal load)
100.59 m / 99.97 m x 15.24 m x 1.68 m

Armament:
1 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1938 Model
Dual purpose gun in deck mount
on centreline aft
8 - 1.10" / 27.9 mm guns in twin mounts, 0.67lbs / 0.30kg shells, 1938 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread
8 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1938 Model
Machine guns in deck mount
on side, all aft, all raised mounts - superfiring
Weight of broadside 19 lbs / 9 kg
Shells per gun, main battery: 300

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

- Conning tower: 1.00" / 25 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 1,667 shp / 1,244 Kw = 12.93 kts
Range 8,000nm at 10.00 kts
Bunker at max displacement = 341 tons

Complement:
150 - 196

Cost:
£0.400 million / $1.602 million

Distribution of weights at normal displacement:
Armament: 2 tons, 0.1 %
Armour: 7 tons, 0.4 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 4 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 3 tons, 0.2 %
Machinery: 46 tons, 2.3 %
Hull, fittings & equipment: 954 tons, 47.1 %
Fuel, ammunition & stores: 234 tons, 11.6 %
Miscellaneous weights: 780 tons, 38.6 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
8,957 lbs / 4,063 Kg = 663.5 x 3.0 " / 76 mm shells or 2.4 torpedoes
Stability (Unstable if below 1.00): 1.17
Metacentric height 2.4 ft / 0.7 m
Roll period: 13.6 seconds
Steadiness - As gun platform (Average = 50 %): 76 %
- Recoil effect (Restricted arc if above 1.00): 0.01
Seaboat quality (Average = 1.00): 1.53

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.785
Length to Beam Ratio: 6.56 : 1
'Natural speed' for length: 18.11 kts
Power going to wave formation at top speed: 27 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 5.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23.00 ft / 7.01 m
- Forecastle (20 %): 16.00 ft / 4.88 m
- Mid (50 %): 16.00 ft / 4.88 m
- Quarterdeck (15 %): 16.00 ft / 4.88 m
- Stern: 16.00 ft / 4.88 m
- Average freeboard: 16.56 ft / 5.05 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 51.4 %
- Above water (accommodation/working, high = better): 287.5 %
Waterplane Area: 14,153 Square feet or 1,315 Square metres
Displacement factor (Displacement / loading): 225 %
Structure weight / hull surface area: 52 lbs/sq ft or 255 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.94
- Longitudinal: 1.81
- 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

Note: draft is average at light ship, with the ballast tanks pumped out. WIth those tanks full, average draft increases to 11 feet, while speed decreases to 12 knots and sea-keeping drops to 1.35.

Note: built to commercial standards for compartmentalization and structure.

As the historical LCM(3) Higgins type. See here http://www.ussrankin.com/id40.htm for more details.

As historical LCT MkVI, see here http://en.wikipedia.org/wiki/Landing_craft_tank for details (though 1938 USN ships are delivered with twin .50s versus single 20mms, 20mms are used in 1939 and later vessels).

As historical LCVP, see here http://en.wikipedia.org/wiki/LCVP for details.

Based on a 1938 design, in 1942 the USN began building LST's in some quantity. 8 are currently planned.

LST-1 laid down 1942
LST-2 laid down 1942
LST-3 laid down 1942
LST-4 laid down 1942
LST-5 laid down 1943
LST-6 laid down 1943

Landing Ship, Tank, United States LST laid down 1942

Displacement:
1,795 t light; 1,840 t standard; 2,023 t normal; 2,169 t full load

Dimensions: Length overall / water x beam x draught
330.01 ft / 328.00 ft x 50.00 ft x 5.50 ft (normal load)
100.59 m / 99.97 m x 15.24 m x 1.68 m

Armament:
1 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1942 Model
Dual purpose gun in deck mount
on centreline forward
8 - 1.10" / 27.9 mm guns (4x2 guns), 0.67lbs / 0.30kg shells, 1942 Model
Anti-aircraft guns in deck mounts
on side, all amidships
8 - 0.50" / 12.7 mm guns in single mounts, 0.06lbs / 0.03kg shells, 1942 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 19 lbs / 9 kg
Shells per gun, main battery: 300

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

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 1,699 shp / 1,267 Kw = 13.00 kts
Range 8,000nm at 10.00 kts
Bunker at max displacement = 329 tons

Complement:
150 - 196

Cost:
£0.452 million / $1.809 million

Distribution of weights at normal displacement:
Armament: 2 tons, 0.1 %
Armour: 3 tons, 0.2 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 3 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 44 tons, 2.2 %
Hull, fittings & equipment: 945 tons, 46.7 %
Fuel, ammunition & stores: 228 tons, 11.3 %
Miscellaneous weights: 800 tons, 39.5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
8,777 lbs / 3,981 Kg = 650.1 x 3.0 " / 76 mm shells or 2.3 torpedoes
Stability (Unstable if below 1.00): 1.17
Metacentric height 2.4 ft / 0.7 m
Roll period: 13.6 seconds
Steadiness - As gun platform (Average = 50 %): 76 %
- Recoil effect (Restricted arc if above 1.00): 0.01
Seaboat quality (Average = 1.00): 1.53

Hull form characteristics:
Hull has a flush deck
Block coefficient: 0.785
Length to Beam Ratio: 6.56 : 1
'Natural speed' for length: 18.11 kts
Power going to wave formation at top speed: 28 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 5.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 23.00 ft / 7.01 m
- Forecastle (20 %): 16.00 ft / 4.88 m
- Mid (50 %): 16.00 ft / 4.88 m
- Quarterdeck (15 %): 16.00 ft / 4.88 m
- Stern: 16.00 ft / 4.88 m
- Average freeboard: 16.56 ft / 5.05 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 52.2 %
- Above water (accommodation/working, high = better): 287.5 %
Waterplane Area: 14,153 Square feet or 1,315 Square metres
Displacement factor (Displacement / loading): 222 %
Structure weight / hull surface area: 52 lbs/sq ft or 252 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.93
- Longitudinal: 1.80
- 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