Double-U is actually called Double-V in Swedish.
But the W seems to have been a lot more common in the old days, and when King Gustav Adolph, a descendent of the founder of the first modern Swedish royal dynasty, Gustav Vasa, wanted to have a great warship built, he called it the Wasa, usually spelled with a W.
This was in the middle of the Reformation in the early 17th century, and Sweden’s Gustav Adolph was the great leader of the Protestant armies, in what became known as the 30 Years War.
To help fight those wars, he had the great ship built in 1628, but on its maiden voyage on the 10th of August that year, the crown of the Swedish navy foundered in a light wind, keeled over and took on water through the open cannon ports, and sank to the bottom of Stockholm harbor.
The king launched an immediate investigation, which turned up that the Wasa was hopelessly top heavy, and when it became clear the culprit was none other than the king himself who had pushed for that design, the investigation was quietly closed down.
The Wasa was forgotten for centuries, but in the 1950’s amateur archaeologist Anders Franzén found the ship on the bottom and led the successful salvaging operation. The Wasa is now in its very own museum in central Stockholm, one of the capital’s most popular tourist attractions.