How many countries were working on building an atomic bomb?

 The United States, Great Britain, Germany, Japan and the USSR were all in possession of nuclear missiles during World War II. So to answer your question, 5.

Ship building industry , good luck : )

The statistics for the eastern war are grim. more than three-million men died in the fighting, more than nine-million men were wounded, and every major country which participated lost its form of government.