Latest Additions to America's Sea Power : f is- ' ' IV - ' ' :! ! X"' - - f - ! Above you see a "mosquito boat" of the U. S. navy zipping across the bows of a freighter In New York harbor during a test run. Officially designated as "P-T" boats, these little craft carry torpedo tubes and machine ma-chine guns in turrets and have terrific speed. Inset: Slipping into the waters of Los Angeles harbor is the 10,000-ton John Paul Jones, its name reminiscent of an earlier American ship. The cost was $1,650,000.