Last summer, we received an extraordinary email from a completely unknown individual. In the email, we were offered the sea atlas from 1914 that was used by Captain Vreugdenhil during World War I. It’s marked with special navigation routes to evade German U-boats. Adrianus Vreugdenhil also invented a directional indicator for sea vessels, but it wasn’t widely adopted because it was unclear to many captains. You can find more information about Adrianus on page 149 of our family tree book.