Crater-class cargo ship is a category of freighter that was constructed for use by the United States Navy during World War II under Maritime Commission EC2-S-C1 type. The class was named for the lead ship of its type, USS Crater (AK-70). There were a total of 62 ships of this class built, the largest count of U.S. Navy cargo ship classes. The ships were propelled by a reciprocating steam engine using a single screw with a power of shaft.