 Some of the vessels were oil-fired and others coal-fired.They were produced by a variety of shipyards on the west coast of the U.S. including Skinner & Eddy and J. F. Duthie & Co. of Seattle, Los Angeles Shipbuilding & Drydock of Los Angeles, California, and the Northwest Steel Company and Columbia River Shipbuilding Company of Portland, Oregon.Most of them were given names starting with the word "West" (or in some cases, "Western"), indicating their west coast origins.