By Land and Sea 109 



vehicles to get twice as many miles per gallon of high-octane 

 gasoline. 



During the first World War the nation spent $3,000,000,000 

 for a fleet of twenty-five hundred ships. But lack of a con- 

 sistent government policy, plus competition from foreign 

 ships supported by their governments and paying their crews 

 lower wages, soon crippled the American Merchant Marine. 

 In a dozen years the United States had only three hundred and 

 forty-seven ocean ships. After Congress passed the Merchant 

 Marine Act of 1936 real progress was made. New, modern 

 ships were built in a program calling for fifty ships a year for 

 ten years. Shipyards were put in good order so that when 

 war came the shipbuilding industry was ready to expand 

 operations rapidly. Officials say the Merchant Marine Act 

 advanced the nation's wartime shipbuilding program by at 

 least two years. 



Shipbuilding Magic 



Prefabrication and welding have enabled American ship- 

 builders to break all records in turning out ships. No longer 

 do they lay the keel and then build upward, riveting one plate 

 at a time until the hull is finished. Today huge two-hundred- 

 ton sections are fabricated near by and then lifted in place by 

 cranes. Prefabrication has enabled Henry J. Kaiser's yards to 

 cut shipbuilding time from months and weeks to days and 

 hours. 



Welding of plates not only saves time but economizes on 

 man power, because one welder can join almost twice as 

 many plates in a day as can a three-man riveting crew. Weld- 

 ing saves steel, because it does away with overlaps and the 

 backup plates behind each seam where the large outer plates 

 come together. Elimination of overlaps, as well as thousands 

 of rivets, cuts down weight and permits ships to carry more 



