Flying Dutchmen

January 10, 2012

Miraged boats

Flying DutchmenPhotographer: Mila Zinkova; Mila's Web Site
Summary Author: Mila Zinkova

January 2012 Earth Science Picture of the Day Viewer's Choice Like many people who live next to an ocean I’ve long been spellbound by the legend of the “Flying Dutchman”. For some time now, I’ve been on the lookout for such a vessel and on a warm, calm day this past November, I got lucky. My eyes were drawn to a ship on the horizon and what a ship it was... it looked as it was cut in slices and floating inside a wave! As I watched, it kept changing appearance. I was sure it was sailed by ghosts – this was indeed the Flying Dutchman. I looked around a little more, saw another such ship and then spotted a small sailboat that had an inverted boat atop it and even more strangely, another one hanging above it in the air (lower photo). To see a Flying Dutchman was eerie but to see several all at once was really quite bizarre. 

There had to be another explanation to these odd apparitions. When I got home, I sent animations of my Flying Dutchmen to Dr. Andrew Young of San Diego State University, asking him how a ship that’s cut in slices could be floating inside a wave. Dr. Young described the scenes thus:

"I think what happens here in the first animation is that the superior mirage includes some of the foreground sea surface, as well as the ship itself. As the mirage changes, there are multiple images of alternately erect and inverted portions of this region that includes the sea horizon. The animation nicely reveals this. So sometimes the 'fold line' of the image includes the ship, and you see a vertically stretched image of the part of the ship near the waterline, sandwiched between two images of the foreground sea surface."

"The second animation, showing interesting short-term changes, also shows a few frames with multiple images of the ship. You can see now and then a bit of sky miraged beneath the ship, where the stacks of cargo on its deck are lowest. I have the impression that waves on the inversion were causing slight oscillations in the structure of this mirage."

So it seems my Flying Dutchmen were mirages of ships sailing along the miraged sea surface with the miraged sky adding to the picture. To someone hoping to see an actual ghost ship this explanation might be just a little bit disappointing. Still, when you visit the seashore, keep your eyes peeled to the horizon – it seems to be a mysterious place.