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LST Class, Allied Landing Ships


Naval Historical Center #97857

Schematic diagram of LST

ONI 226


Specifications:


Tonnage 2400 tons loaded for landing operations
Dimensions 327' by 50' by 13'
99.7m by 15.2m by 4.0m
Maximum speed      11 knots
Complement 119
Armament 13 0.50 machine guns
6 20mm Oerlikon AA guns
Cruising speed
8 knots
Machinery
2-shaft diesel (1800 shp)
Range
12,000 nautical miles
Capacity 20 medium tanks or 750 tons cargo
Modifications
Beginning in late 1943, LSTs began shipping additional antiaircraft armament. This typically brought the antiaircraft battery up to 3 to 5 40mm Bofors AA guns, 11 to 18 20mm guns, 4 to 18 machine guns, and one 3"/50 AA gun.

By the end of the war, 8 40mm guns was standard armament.


Landing Ships, Tank, or LSTs, were designed to land up to twenty tanks on a beach.  The design dated to November 1941, when a British delegation to the United States asked for 200 ships and 400 craft capable of bringing tanks ashore. The former became the LSTS and the latter the LCTs.

LSTs had rather light point defenses and were quite slow, so that some wags claimed that “LST” stood for “Large Slow Target.” In light of experience gained at New Georgia, LSTs in the South Pacific shipped many additional antiaircraft guns by the time of the Bougainville landings. The ships were also equipped with barrage balloons, but these were discarded in 1944 because they were too visible to enemy search aircraft.

South Pacific LSTs were rarely used for their designed purpose of bringing vehicles ashore. Instead, they were used to land large quantities of supplies. At first, cargo was stacked to the rear of a few preloaded trucks. The trucks would discharge their cargo, then come back to be loaded with more, while additional cargo was manhandled onto the beach. This allowed about four times as much cargo to be carried as would have been the case if all the cargo had been preloaded onto trucks, but the unloading process was slow, taking about eight hours. The process was improved by loading the cargo into trailers that could be hauled ashore by tractors. About 33 trailers could be packed into an LST with little loss of cargo capacity, and unloading was much faster: An LST so loaded could discharge about 750 tons of cargo in about two hours.

LSTs were designed for a beach slope of 1 in 50. On this ideal beach, an LST would ground evenly along her entire length and her ramp would come down on dry ground. On shallower beaches, the ramp would drop into the water, and the gap had to be bridged with interlocking pontoon units. On deeper beaches, the LST did not ground properly and was liable to yaw dangerously in the surf. In either case, the uneven grounding put considerable strain on the hull. Because few beaches were ideal, an LST was too badly worn out for further use in landing operations after about ten landings. The Navy judged that it was more cost-effective to build new LSTs than to refurbish the old ones or to try to strengthen the design. The old, worn-out LSTs were used for every imaginable purpose, including repair ships, floating barracks, floating depots, and hospital barges. Some were even fitted with a flight deck capable of operating a handful of light reconnaissance aircraft — a dubious concept at best.

A number of LSTs were modified by converting part of the troop deck into a small surgical suite. LST-464 was converted into a dedicated hospital ship, with a surgical suite, X-ray room, laboratory, and isolation ward. She began service off New Guinea with 7 Fleet and served with great distinction in the second Philippines campaign.

LSTs were considered a sufficient priority early in the war that, on 28 May 1942, a number of Maritime Commission shipyards were instructed to begin mass production of the ships (as standard type S3-M2-K2). Some 75 LSTs were produced by Maritime Commission shipyards, including 15 at a new yard near Oakland (Richmond #3a, later redesignated Richmond #4) and 30 at Vancouver, which had previously completed just two Liberty Ships.The priority given to construction of LSTs significantly delayed the destroyer escort program.


Units arriving in the Pacific:

2/42

1

11/42 5
12/42      10
1/43 9
2/43 10
3/43 12
4/43 12
5/43 17
6/43 7
7/43 8
8/43 15
9/43 21
10/43 13
11/43 5
3/44 3
4/44 22
5/44 65
6/44 39
7/44 44
8/44 41
9/44 42
10/44 34
11/44 39
12/44 27
1/45 43
2/45 13
3/45 1
4/45 1
Total 559

Photo Gallery


Profile of LST

U.S. Navy

Forward hull of beached LST

U.S. Navy

Stern hull of beached LST

U.S. Navy

Doors of beached LST

U.S. Navy

Doors of beached LST

U.S. Navy


References

Cowdrey (1994)

Friedman (2002)

Leighton and Coakley (1955)

Morison (1950)

NavSource.Org (accessed 2009-10-1)


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