Even for 1924, this is a pretty racist and jingoistic book, looking down on several cultures for the sake of "enlightening" red-blooded, all-American boys. It's got a few intriguing bits of exposition about ships of the era, but otherwise this is just a few shades to the left of the racist iconography of Sax Rohmer. If you want to know about wireless operators, there are numerous other, less obnoxious series from this era to read.