USCGC Chock (WYTL-65602), Data Sheet (26 SEP 2012), U.S. Coast Guard They were designed with steel hulls to replace the 64 feet wooden-hulled tugs that had been in service since the 1940s and were built by Gibbs Gas Engine Company, Jacksonville, Florida; "Gibbs Gas Engine Company"' Small Shipbuilders and Boatbuilders List, Shipbuilding History.com Barbour Boat Works of New Bern, North Carolina; "Barbour Boat Works", Small Shipbuilders and Boatbuilders List, Shipbuilding History.com and Western Boat Builders Corporation, Tacoma, Washington "Western Boat Builders Corp.", Small Shipbuilders and Boatbuilders List, Shipbuilding History.com from 1961 to 1967.