LSM (Landing Ship, Medium)



General Information

General Measurements
Length 203.5 feet
Beam 34.5 feet
Speed 13.3 knots
Endurance 4,900 miles (12 kts)
 
Weights
Displacement (Light) 520 tons
Displacement (Loaded) 900 tons
Payload (Beaching) 150 tons
 
Crew (Typical)
Officers 4
Enlisted 54
 
Standard LSM Armament
1 - 40mm Cannon Twin Mount
4 - 20mm Cannons
 
LSM 275 Armament
1 - 40mm Cannon Single Mount
4 - 20mm Cannons
2 - 12.7mm Machine Guns
 
General Information
Number of LSM's Constructed - 558


Size Comparison

This graphic illustrates the comparative size of various amphibious units.

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Ship Plans

This illustration shows the interior layout of an LSM.

I will be updating this graphic as more information becomes available!

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LCT, LSM and LST Comparison Chart

This illustration shows the basic capabilities of LCTs, LSMs and LSTs.

Some of the figures are approximations as many of the published sources disagree.

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LSM Armament Layout

This illustration shows the armament layout of several LSM variants.

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Amphibious Force Acronyms

LCAC
LCC
LCI
LCM
LCT
LCU
LCVP
LHA
LHD
LPD
LPH
LSD
LSM
LST
LVT
Landing Craft, Air Cushioned
Command Ship
Landing craft, infantry
Landing Craft, Mechanized
Landing Craft, Tank
Landing Craft, Utility
Landing Craft, Vehicles and Personnel
Helicopter Assault Ship
Helicopter Assault Ship
Amphibious Transport Dock
Amphibious Assault Ship
Landing Ship, Dock
Landing Ship, Medium
Landing Ship, Tank
Landing Vehicle, Tracked


LSM / LSM-R Losses During WW2

Source: Naval Historical Center
LSM-12 foundered after being damaged by a Japanese suicide boat off Okinawa, 4Apr1945.
LSM-20 sunk by Kamikaze attack off Ormoc, Leyte, Philippine Islands, 5Dec44.
LSM-59 sunk by Kamikaze attack off Okinawa, 21Jun45.
LSM-135 sunk by Kamikaze attack off Okinawa, 25May45.
LSM-149 grounded off the Philippine Islands, 5Dec44.
LSM-318 sunk by Kamikaze attack off Ormoc, Leyte, Philippine Islands, 7Dec1944.
LSMR-190 sunk by Kamikaze attack off Okinawa, 4May45.
LSMR-194 sunk by Kamikaze attack off Okinawa, 4May45.
LSMR-195 sunk by Kamikaze attack off Okinawa, 3May45.


Brief History of the LSM 275

  • Laid down, 1 August 1944, as LSM-275 at Federal Shipbuilding and Drydock Co., Newark, NJ.
  • Launched, 11 September 1944.
  • Commissioned USS LSM-275, 6 October 1944, LT. Daniel D McLoed, USNR in command.
  • During World War II LSM-275 was assigned to the Asiatic-Pacific theater.
  • Participated in the Assault and Occupation of Okinawa Gunto, 2 to 29 April 1945.
  • Decommissioned, 21 April 1947 at Terminal Island Navy Yard, San Pedro, CA; Laid up in the Pacific Reserve Fleet
  • Redesignated a Cable Repair Ship, 14 December 1951.
  • Recommissioned, USS Portunus (ARC-1), 2 July 1952.
  • Decommissioned, 30 April 1959, at New York.
  • Struck from the Naval Register, 1 May 1959.
  • Transferred, 16 November 1959, under the Military Assistance Program, to Portugal.
  • Commissioned into the Portuguese Navy, 18 November 1959 as Medusa (A 5214).
  • Final Disposition, disposed of by Portugal, 1976.


LSM Related References

     Lsm - Lsm (R) - Landing Ship Medium
     by Rolf F. Illsley

     Hardcover: 168 pages
     Publisher: Turner Pub Co;
     ISBN: 1563111403; (January 1997)
     This book is currently available on Amazon.com.
     The price is $49.95.



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