This story has been told many times before – it may be the IP lawyer's favorite bedtime story.  But in this centenary year of the birth of the inventor, it's worth telling again.  It might even be true.

In 1964, a Danish inventor, Karl Krøyer, was faced with an interesting technical problem: the freighter Al-Kuwait had capsized off Kuwait harbor, carrying with it to the bottom its cargo of several thousand sheep.  Krøyer's job was to find an economical way of raising the ship in order to save the insurance company from having to pay out the $2 million for which the ship was insured, preferably before the sheep started decomposing.  His solution: drop a tube down to the ship, and pump in gas-containing polystyrene balls having a size of between 5 and 16 mm.  The polystyrene balls would displace the water, and being buoyant, would float the ship as soon as enough of them were injected.  27 million polystyrene balls later, the ship was raised at a cost of only $345,000 – problem solved!  (I have not been able to find out whether that included the cost of replacing the sheep.)  According to a New York Times article (19 February 1971), the process was used successfully at least three more times in the following years, and the Egyptian government had expressed an interest in using it to raise ships that were blocking the Suez canal following the Six-Day War.

Krøyer received patents for his method in Great Britain (GB1070600) and Germany (DE1247893).  Shown here is Figure 1 of the British patent:

The parallel Dutch patent application (NL6514303) was rejected, however.  According to the story, the Dutch examiner discovered (or remembered having read) the 1949 Donald Duck story "The Sunken Yacht," written by Carl Barks.  In this story, Donald and his nephews raise a sunken vessel by pumping it full of ping pong balls, which displace the water and float the vessel:

The examiner reportedly concluded that the Donald Duck cartoon was legitimate prior art relative to Krøyer's invention, as it either anticipated Krøyer's invention, assuming that the cartoon as published could be considered to provide an enabling disclosure, or that at worst Krøyer's invention would have been considered obvious in light of the published cartoon.  Since Krøyer and the examiner have long since passed on, and the documentation long since destroyed, it appears that no one knows for sure the exact grounds of the rejection.

In any case, whether it actually happened that way or not, the story of Donald Duck and the Dutch Patent Office provides an important lesson for applicants for patents and their representatives: any document can be considered relevant prior art as long as it provides an enabling disclosure and is available to the public – even if the document is a comic book.

And it also perhaps provides another lesson:  when your mother told you that you were rotting your brain with all of those comic books, you could have responded that you were reading important reference materials for your future career as an IP lawyer (or as a patent examiner).