Sunday, February 12, 2017

The Story of the Wasa - Part 5, Causes, Conservation, and Legacy



                                                     Structure of the Wasa above the waterline

It is clear that the Wasa sank because she was unstable and not seaworthy.  She carried too large a percentage of weight above the waterline.  This is not the result of the weight of the armaments.  Rather it is the hull design itself which didn’t allow room for sufficient ballast.  Failed stability tests were ignored.  But there were many additional factors which contributed to the sinking.

Sweden was engaged in war with Poland.  The King desperately needed a new warship for success.  But he was unable to have direct contact with the designers and contractors of the vessel since he was out of the country.  Nonetheless, no expense was spared in building the Wasa.  Funding was not an issue.  But changing requirements and schedules were.  The Wasa was originally conceived as a small traditional vessel but became a large innovative vessel.

The changing requirements had some unintended consequences.  To expedite the construction, both Swedish and Dutch shipwright teams were used.  These teams used different measuring systems.  The Swedish foot measures 12 inches while the Dutch foot measured only 11 inches.  This caused the ships mass to be unevenly distributed and heavier on the port side.  The addition of a second gun deck caused a conflict between seaworthiness and military firepower.  This resulted in an unavoidably large amount of weight above the waterline.

                                                Upper and Lower Gun Ports of the Wasa 
Even then the Wasa probably would not have sunk if her gun ports had been closed.  The normal procedure was for vessels with multi-tiered gun decks was to sail with the gun ports closed.  It was not unusual for wind pressure to push the lower row of gun ports below the water.  It is believed Wasa’s gun ports were open in order to fire celebratory shots as part of the maiden voyage send off.  It was too late to save the Wasa by closing her gun ports after she began taking on water.

Wasa Lion Figurehead as recovered 
Even though the Wasa was in remarkable condition after spending 330 years submerged in the Baltic Sea, allowing her to dry out by simply bring her to the surface would have caused a greatly accelerated rate of deterioration.  There have been numerous research projects to determine the optimum way to preserve the ship and its contents.  Special buildings were constructed to house the Wasa and facilitate keeping her hydrated.  The primary method of conservation was impregnation of the entire vessel with polyethylene glycol (PEG).  She was continuously sprayed with PEG for a period of 17 years.  This has been followed by a long period of controlled slow drying under stringent temperature and humidity control.

                                                     Wasa Lion Figurehead as restored 
The Wasa currently resides in the Wasa Museum in Stockholm.  The goal of this museum is to present the vessel and a nearly original condition for public display.  Features that needed to be rebuilt used as many original parts as possible.  It is estimated that 95% of the ship today is made up of original materials.  The Wasa quickly became a Swedish national treasure.  The ship and museum are a major tourist attraction.   The story of the Wasa has been the the subject of numerous books articles and papers.  Several children’s books have been written about her.  Custom-built models and model kits are available.


Ship Models Online offers two beautiful scratch built wooden quality tall ship models of the Wasa in different sizes.  


This is the last in a series of five blog posts relating the Story of the Wasa.  I hope you have found this series enjoyable.  I would be very interested in any comments you may have about these articles.








References include:
Vasa (ship) from Wikipedia
The Swedish Ship Vasa’s Revival by Dottie E. Mayol, Univ. of Miami
Why the Vasa Sank: 10 Lessons Learned by R. Fairley

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