Friday, April 26, 2013

Saving the Vasa

   The 17th century Swedish warship Vasa set out on its maiden voyage as symbol of military power and a source of national pride. King Gustavus II Adolphus, in the midst of a troublesome conflict with Poland, needed his new weapon to revolutionize naval warfare in the Baltic. As a result of his interjections, engineers increased Vasa’s originally intended length and added an additional gun deck to hold heavy cannon, ensuring its place among the elite warships of the world. Measuring 69m in length and 52m in height, weighing 900 tons, and carrying 64 cannons, Vasa launched on August 10, 1628 before a massive crowd that had assembled to catch a glimpse of Sweden’s new floating behemoth. Roughly 1km into its first trip, a gust of wind blew the top heavy ship onto its side. Water flooded into gun ports that were open for ceremonial fire, quickly pulling Vasa and half of its crew 35m down to the bottom of Stockholm harbor.
   Vasa’s sinking granted it a unique position in history. The doomed ship represents both an impressive logistical endeavor and a colossal economic failure. Designed to intimidate enemies and inspire allies, it was visually stunning and physically overwhelming, but its construction cost over five percent of the nation’s GNP and its loss was catastrophic. Perhaps this duality factors in Vasa’s ability to intrigue the public.

   After being rediscovered in 1956 and raised to the surface in 1961, painstaking efforts toward preservation were immediately undertaken. Oxygen deprived conditions at the bottom of the cold, polluted harbor kept Vasa well protected from destructive organisms, leaving it in remarkably good shape. However there was some degradation, which becomes a problem as the water logged wood dries and collapses around the compromised area. To prevent this shrinking and crumbling of the hull, it was sprayed with polyethylene glycol (PEG): a wax compound that absorbs into the wood and takes the place of water. This was done every 45 minutes for 17 years, after which the wood was allowed to dry for nine years. In 1988, Vasa was moved into a climate controlled building that both preserves the ship and presents it as a primary museum display.

Boarding Vasa is forbidden, but you can get pretty close

Note the elaborate designs. These carvings would have originally been pigmented quite colorfully
   The Vasa Museum, while nearly as visually impressive as its namesake, has not been the ideal environment for the aging warship it was intended to be. After a particularly rainy year of 2000, it was discovered that humidity levels needed to be more strictly regulated in the museum. The problem arose due to PEG’s tendency to absorb and desorb atmospheric moisture. If conditions are too humid, destructive micro-organisms can thrive and wreak havoc on the exterior. Additionally, the increased water weight could put overwhelming strain on a hull that wasn’t designed to support the weight of the vessel on land in the first place. If allowed to dry out, the wood could weaken and crack, endangering critical support joints. If that wasn’t enough to worry about, humidity fluctuations cause moisture to transfer throughout the wood. This moves sulfur, imbedded into the wood during its stay in the polluted harbor, to open air where it can react with corroded iron from bolts and fittings, creating an erosive acid compound. In order to keep the humidity at an appropriate, constant level and prevent all of this microscopic mayhem, a new, more effective climate control system was installed in 2004 and a vast array of sensors are constantly being monitored and upgraded. This has resulted in a far more stable environment for the delicate Vasa.

Vasa Museum
  Fittingly, Vasa’s new challenge is economic. All of this restoration and preservation is wildly expensive. Fortunately, people love the Vasa and its museum is the most widely visited maritime museum in the world. However, due to concerns with the limitations of the climate control system, the number of daily visitors is capped. Economically driven demands to allow entrance to larger numbers of paying customers are now pushing against fears that the building's climate will be compromised. This is the delicate balancing act that Vasa’s caretakers have to manage if Sweden’s most beloved naval disaster is going to survive half as much time above the harbor as it did below.

More Info:
Time Capsule from the 17th Century: Stockholm's Vasa Museum

Maintaining a Stable Environment: Vasa's New Climate Control System

The Chemistry of the Vasa 


  1. Nice Article Cory. Interesting how it is displayed; hung, in addition to it being mounted on a base. Seems destined to capsize. Also had no idea how popular the Vasa museum was...too bad nobody had the balls (or ballast, as the case may be) to tell Gus his impatient desire for power and pride was as top heavy as his ship.

  2. Great archaeological find and restoration success story.