
Type C1 was a designation forcargo ships built for theUnited States Maritime Commission before and duringWorld War II. Total production was 493 ships built from 1940 to 1945. 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 toPearl 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 includingtroop transports during the war.
The Type C1-M ship was a separate design, for a significantly smaller and shallowerdraft vessel. This design evolved as an answer to the projected needs for military transport and supply of thePacific Ocean theater of World War II.[1]
Type C1 ships under the control of the BritishMinistry of War Transport took anEmpire name even if built with another name e.g.Cape Turner.
TheUnited States Maritime Commission (MARCOM) was anagency of the United States government that was created by theMerchant Marine Act of 1936, passed byCongress on 29 June 1936 and replaced theU.S. Shipping Board which had existed sinceWorld 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, includingHog Islander ships, that comprised the bulk of theU.S. Merchant Marine. These old standardized ship designs ranged in size from5,075dwt to7,500dwt,8,800dwt and9,600dwt for the most common mass-produced types. They either had steam turbines or triple expansion engines, burning oil their boilers. None of the World War I standard designs had diesel engines.
From 1939 through the end ofWorld War II, MARCOM funded and administered the largest and most successful merchant shipbuilding effort in world history, producing thousands of ships, includingLiberty ships,Victory ships, and others, notably type C1 ships,type C2 ships,type C3 ships,type C4 ships,T2 tankers,Landing Ship Tank (LST)s and patrolfrigates. 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.
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.[2]
The Type C1-A and C1-B ships were similar in design, All had a rated top speed of 14knots (26 km/h; 16 mph). The primary difference between them was that C1-A ships were shelter deck ships, while C1-B ships were fullscantling ships. 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.
The C-1 (A and B variants) employed two kind of propulsion systems. One group comprising 19 C1-A, 85 C1-B and all 13 C1-S-AY1 used 4,000 hpcompound turbines (one high pressure and one low pressure turbine) and turbo-electric generators for auxiliary power. The other group of 46 C1-A and 10 C1-B used two 2,000 hp diesel engines connected to a single reduction gearset viamagnetic couplings, in the same family as the system used onvarious C3 ships where four such engines were coupled to one gearset for a total of 8,000 hp. The C1-M variant used diesel propulsion exclusively, but only a single 2,000 hp range engine and without magnetic couplings. All turbines and diesel engines were sourced from a variety of manufacturers.
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 asSS Cape Hatteras.

Forty-six Type C1-A ships were built atPennsylvania Shipyards, Inc. inBeaumont, Texas, with another 19 being built byPusey and Jones inWilmington, Delaware (not to be confused withConsolidated Steel'sWilmington, California location). The majority 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 firstkeels werelaid in 1939. Two of the Pusey and Jones ships were converted toPT boat tenders before entering service, includingUSS Cyrene.
Some of the diesel vessels were powered by 2, 6-cylinder Nordberg 2-stroke engines (Sulzer type) driving the single shaft via magnetic couplings and a reduction gear-box. They were manufactured byNordberg Manufacturing Company. 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.
Converted to Troop Ships[3][2]
4 Modified and redesignated (toUnited States Navy)

The Type C1-B ships were built in eight different yards, all but 15 in West Coast yards, all but 20 in California, the majority atConsolidated Steel Corporation inWilmington, California. All but ten of the C1-B ships had steam turbine engines; the diesels were all built atSeattle-Tacoma SB Corp.,Tacoma, Washington andWestern Pipe & Steel, San Francisco, California, with each producing five ships. The C1-B 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. A C1-B example and perhaps the most well-known was theSS Flying Enterprise.
In 1939, under theLong Range Shipbuilding Program, contracts for 38 ships in batches of 2 to 5 vessels were awarded after one round of competitive bidding.Bethlehem San Francisco andBethlehem Staten Island only produced on this occasion for the Maritime Commission. ForSeattle-Tacoma, the C1-B contract prompted the reopening (and rebuilding) of the Tacoma yard.Consolidated Steel entered the shipbuilding business in 1939. Timing makes these ship constructions interesting, as they were on slipways when the U.S. shipbuilding industry was going through the transition of 1940/1941 towards war time production and many ships, whether afloat or building, were reassigned to fulfill new duties. Unsuccessful bids were made by theGeneral Engineering & Dry Dock Company, theTampa Shipbuilding and Engineering Company, the Newburgh Shipbuilding and Repair Company of New York, theSun Shipbuilding and Dry Dock Company, theLos Angeles Shipbuilding and Dry Dock Company. Bids (for either C1-A or C1-B in either steam of diesel variants) were opened on 11 July 1939.Pusey and Jones successfully bid on 2 C1-A ships.[4] Contracts were awarded in September 1939.[5] Two of these early-built ships joined the ship launching parade of theLiberty Fleet Day on 27 September 1941.
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after the Emergency Shipbuilding Program picked up momentum,Consolidated Steel remained the only manufacturer of the C1-B type.
Converted to Troop Ships[3][2][6] (all steam turbine driven)
7 Modified and redesignated (toUnited States Navy) (all steam turbine driven)
The C1-S-AY1 subtype of thirteen ships built byConsolidated Steel Corporation was modified from the C1-B design for use as troopships by Great Britain underlend-lease calledLanding Ship Infantry, Large and they were originally ordered as troopships. These ships were all given two-word names beginning with "Empire", such asSSEmpire Spearhead.Empire Broadsword was lost at theNormandy Invasion, to a mine.Empire Javelin was sunk by a torpedo from a GermanU-boat on 28 December 1944. The originalCape names are what the ships were launched as and by which name they were known to theMaritime Commission.
Twenty-four concrete C1-S-D1 ships were made byMcCloskey & Company Shipyard in Hookers Point,Tampa, Florida in 1944. Many were sunk during or after the as war as breakwater barriers.



Thediesel (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 thePacific. These ships were shorter, narrower, and had less draft than the earlier C1 designs, and were rated at only 11 knots (20 km/h).USS Alamosa is an example of a C1-M ship.
TheC1-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 forknots, such asMS Acorn Knot, or with a two-word name beginning with "Coastal", such asMS Coastal Sentry; 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 theU.S. Navy, like theUSSGadsden built byWalter Butler Shipyard. Those ships were generally named aftercounties in the U.S. C1-M-AV1 ships are aAlamosa-class cargo ships.
OneC1-ME-AV6 (also called C1-M-AV7[8]) subype was built,MS Coastal Liberator. Instead of the diesel engine direct drive of the AV1 subtypes, it useddiesel-electric drive. The diesel engine powered a generator to produce electricity, and an electric motor with 2,200 horsepower (1,600 kW) actually propelled the vessel.
Four of theC1-MT-BU1 subtype were built as lumber carriers, with twin screws. The lumber carriers were given U.S. State-and-tree names, such asMS California Redwood. Built byAlbina Engine & Machine Works, Portland, Oregon.
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.
Modified and redesignated
Most 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 used the ex "Pembina" built in Superior Wisconsin and renamed theSpirit of Grace until she was removed in 2006 and scrapped in 2008.
| Ship type | C1-A Shelter deck | C1-B full scantling | C1-M |
|---|---|---|---|
| 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 | — |
| 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) |
| Type | Quantity | Naming scheme |
|---|---|---|
| C1-A | 65 | "Cape" names,SS Cape Hatteras,SS Cape St Elias |
| C1-B | 95 | also "Cape" names, other names, specific shipping lines names includeSS Mormacgull (II) |
| C1-S-AY1 | 13 | took "Empire" names after transfer to the BritishMinistry of War Transport, several becameLanding Ship, Infantry (Large) such asSS Empire Spearhead |
| C1-S-D1 | 24 | most named after individuals |
| C1-M-AV1 | 217 | "Knot" ships,MS Emerald Knot "Coastal" ships,MS Coastal Ranger |
| C1-MT-BU1 | 4 | "Tree" ships,MS California Redwood, by Albina Engine |
| C1-ME-AV6 | 1 | Only one,MS Coastal Liberator |
| C1-M-AV8 | 11 | Originally knots |
Note any ship in the control of the BritishMinistry of War Transport took anEmpire name even if being built as another name e.g.Cape Turner
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