When Vasa was raised in 1961, the question of how to preserve such a large wooden ship became paramount. For the researchers, the conservation of all the artifacts found by the divers at the wreck site became a serious challenge and they tested several new preservation methods.

Directly after the ship was salvaged it was sprayed with water so that it wouldn't dry out, split and collapse. Afterwards, Vasa was sprayed for 17 years with the preserving agent PEG - Polyethyleneglycol (polly-ethel-lean-gly-call) after which it dried for a further 9 years.

Today the ship weighs nearly 900 tons, about as much as 6 jumbo jets. It's exactly like all ships, which are designed to always be in the water where the weight of the hull is evenly supported by the water. Vasa currently sits in a cradle where the hull is supported by a series of stanchions and is therefore at risk of being damaged. However, a new cradle is planned where the ship’s weight will be distributed in a more appropriate manner.

With the help of over 400 measurement points on the Vasa, even the smallest movement of the ship’s hull can be observed from measurement stations in the ship hall. The measurements indicate that the hull is sinking about one millimeter per year and twisting slightly.

Vasa's hull is built of thousands of parts which are held together with over 5000 iron bolts and 30,000 wood treenails. Some of the bolts are nearly 2 meters long in order to span the thickness of the ship’s massive components.
One problem has been that the original iron has rusted away, which in turn has set off chemical reactions which could eventually destroy the wood. So now, a pilot project has begun to replace the iron bolts with carbon fiber and stainless steel duplicates.

After having had problems with the air in the ship hall, a new climate control system was installed in 2004. Now the climate in the museum is stable at around 55% humidity and 18.5 degrees Celsius, an ideal combination for the ship.

The work of preserving Vasa is a journey of discovery without end. Never before had anything similar been done and all that we learn during the course of our work will be of immense help in preserving wooden ships around the world.