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File:C1-A clean in water.jpg

Type C1-A freighter USS Fomalhaut circa 1944

Type C1 was a designation for small cargo ships built for the U.S. Maritime Commission before and during World War II. The first C1 types were the smallest of the three original Maritime Commission designs, meant for shorter routes where high speed and capacity were less important. Only a handful were delivered prior to Pearl Harbor. But many C1-A and C1-B ships were already in the works and were delivered during 1942. Many were converted to military purposes including troop-transports during the war.

The Type C1-M ship was a separate design, for a significantly smaller and shallower draft vessel. This design evolved as an answer for the projected needs for military transport and supply of the pacific island campaigns.


The United States Maritime Commission (MARCOM) was an independent executive agency of the US Federal government that was created by the Merchant Marine Act of 1936, passed by Congress on 29 June 1936 and replaced the U.S. Shipping Board which had existed since World War I. It was intended to formulate a merchant shipbuilding program to design and build five hundred modern merchant cargo ships to supplement and replace the World War I vintage vessels, including Hog Islander ships, that comprised the bulk of the U.S. Merchant Marine.

From 1939 through the end of World War II, MARCOM funded and administered the largest and most successful merchant shipbuilding effort in world history, producing thousands of ships, including Liberty ships, Victory ships, and others, notably type C1 ships, type C2 ships, type C3, type C4 ships, T2 tankers, Landing Ship Tank (LST)s and patrol frigates. By the end of the war, U.S. shipyards working under MARCOM contracts had built a total of 5,777 oceangoing merchant and naval ships.

What was later known as the C1-A was among the three original cargo ship designs including the basic C2 and C3. The further developments included the C1-B which included minor changes and turbine engines, and then more radical departures for special needs to meet the exigencies of the war, including troop ships based on the C1-B. Deliveries of the C1-B began before the other models, in mid 1941.

The C series of ships differed from the Liberty and Victory ships. The first C series vessels were designed prior to hostilities and were meant to be commercially viable ships to modernize the US Merchant Marine, and reduce the US reliance on foreign shipping. The Liberty ships were a throwback to late 19th century British designs with reciprocating steam engines, but were very cheap to build in large quantities; Victory ships evolved from the Liberty ships but used modern turbine engines. The C series ships were more expensive to produce, but their economic viability lasted well into the late 1960s and early 1970s in military and merchant fleets. Several ships are still in operation.


The Type C1-A and C1-B ships were similar in design, All had a rated top speed of 14 knots. The primary difference between them was that C1-A ships were shelter deck ships, while C1-B ships were full scantling ships. There were many adaptations of the design for special purposes from hospital ships to petroleum gas carriers. The C1-M was the type with the largest production; it was a significant variation from the original C1 design in size, performance and profile; these were shorter, narrower, slower and the superstructure was farther toward the stern.

With the exception of ships built for specific shipping lines before the war, the majority of the C1-A and C1-B ships were given two-word names beginning with "Cape", such as SS Cape Hatteras.


Forty-six Type C1-A ships were built at Pennsylvania Shipyards, Inc. in Beaumont, Texas, with another 19 being built by Pusey and Jones in Wilmington, Delaware. Most were built with diesel motors, though 19 were built with steam turbine engines. These were shelter deck ships, having a very light upper deck, the sides of which are open ports to the second or main deck.

The first keels were laid in 1939. Two of the Pusey and Jones ships were converted to PT boat tenders before entering service, including the USS Cyrene (AGP-13).

Some of the diesel vessels were powered by 2- to 6-cylinder Nordberg 2-stroke engines (sulzer type) driving the single shaft via magnetic couplings and a reduction gear-box. The engine speed was 220 rpm and the shaft 110 rpm. This configuration made maneuvering very easy when entering port, as one engine was run in reverse and the other ahead; change of direction was simply performed by energizing the appropriate magnetic coupling. All auxiliary equipment was electric. The engine room was a pleasure to operate and the workmanship outstanding.


The Type C1-B ships were built in six different yards, the majority at Consolidated Steel Corporation in Wilmington, California. All but ten of the C1-B ships had steam turbine engines; these were all built at Seattle-Tacoma SB Corp., Tacoma, Washington and Western Pipe & Steel Co., San Francisco, California, with each producing five ships. These were full scantling ships with three decks in which the frames hold the same dimensions as the upper deck. Full scantling ships have deck gear sufficient to completely unload their cargoes.

The C1-S-AY1 subtype of thirteen ships built by Albina Engine & Machine Works, Portland, Oregon, was modified from the C1-B design for use as troopships by Great Britain under lend-lease. These ships were all given two-word names beginning with "Empire", such as SS Empire Spearhead. The Empire Broadsword was lost at the Normandy Invasion, to a mine. Empire Javelin was sunk by a torpedo from a German U-boat on 28 December 1944.


USS Alamosa - typical Type C1-M vessel

The diesel (M for Motor) powered C1-M Type ships were a separate design from the C1-A and C1-B, meant for shorter runs and shallow harbors, either along the coasts, or for "island hopping" in the Pacific. These ships were shorter, narrower, and had less draft than the earlier C1 designs, and were rated at only 11 knots (20 km/h). The USS Alamosa is an example of a C1-M ship.

The C1-M-AV1 subtype, a general cargo ship with one large diesel engine, was the most numerous. About 215 of this type were built in ten different shipyards. Consolidated Steel Corp., Ltd. of Wilmington, California built the largest number — about a quarter of all built. These ships were either named for knots, such as SS Emerald Knot, or with a two-word name beginning with "Coastal", such as SS Coastal Ranger; a large number built for lend-lease were also given two-word names, this time beginning with "Hickory". About 65 of this subtype were complete for the U.S. Navy. Those ships were generally named after counties in the U.S.

One C1-ME-AV6 subype was built, SS Coastal Liberator. Instead of the diesel engine direct drive of the AV1 subtypes, it had a diesel engine which produced electricity, and an electric motor with 2,200 horsepower actually powered the vessel. Four of the C1-MT-BU1 subtype were built as lumber carriers, with twin screws. The lumber carriers were given U.S. State-and-tree names, such as SS California Redwood.

The final subtype, C1-M-AV8, had a variable pitch propeller. Only one ship was planned as this type, but five previously launched C1-M-AV1 ships were converted to this type for France.

Final disposition

Many of these ships have been sold and scrapped but numerous examples are still in service with Non Governmental Organizations (NGO)s such as "Friend Ships". That organization is still using the ex "Pembina" built in Superior Wisconsin and currently called the "Spirit of Grace". Several are sailing in merchant service around the world making port calls and delivering cargo.

Type C1 specifications

Type C1-A
Shelter deck
full scantling
Length overall 412.25 ft (125.6 m) 417.75 ft (127.3 m) 338.5 ft (103.2 m)
Beam 60 ft (18.3 m) 60 ft (18.3 m) 50 ft (15.2 m)
Depth 37.5 ft (11.4 m) 37.5 ft (11.4 m) 29 ft (8.8 m)
Draft 23.5 ft (7.2 m) 27.5 ft (8.4 m) 18 ft (5.5 m)
Gross tons 5,028 6,750 3,805
Deadweight tons, steam 6,240 7,815 N/A
Deadweight tons, diesel 6,440 8,015 5,032
Speed 14 knots (26 km/h) 14 knots (26 km/h) 11 knots (20 km/h)
Power 4,000 hp (3,000 kW) 4,000 hp (3,000 kW) 1,750 hp (1.300 kW)

Quantities of Type C1 ships

Type Quantity Naming Scheme
C1-A 67 "Cape" names, SS Cape Hatteras, SS St Cape Elias
C1-B 95 also "Cape" names, other names, specific shipping lines names include SS Mormacgull (II)
C1-S-AY1 13 took "Empire" names after transfer to the British Ministry of War Transport, several became Landing Ship, Infantry (Large) such as SS Empire Spearhead
C1-M-AV1 217 "Knot" ships, SS Emerald Knot
"Coastal" ships, SS Coastal Ranger
C1-MT-BU1 4 "Tree" ships, SS California Redwood
C1-ME-AV6 1 Only one, SS Coastal Liberator
C1-M-AV8 11 Originally knots

Note any ship in the control of the Ministry of War Transport took an Empire name even if being built as another name e.g. Cape Turner

See also

Type C1 ships


  • From America to United States: The History of the long-range Merchant Shipbuilding Programme of the United States Maritime Commission, by L.A. Sawyer and W.H. Mitchell. London, 1981, World Ship Society
  • Ships for Victory: A History of Shipbuilding under the U.S. Maritime Commission in World War II, by Frederic C. Lane ISBN 0-8018-6752-5

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