No fancy equipment is needed to find the Flying Dutchman (aka: De Vliegende Hollander) in the waters of Luzon Strait in Silent Hunter 4, even in stock trim. He has been known to haunt those waters since the 17th Century's golden age of the Dutch East India Company (VOC). Supposedly, it still traverses those waters, searching for a port it can never land. Legend has it that sighting his ship is a portent of doom...
Some naysayers say it's an optical illusion, a "superior mirage" or "Fata Morgana", seen at sea by those suffering from not using the facilities often enough. A back-up of B.S., if you will...