The reason that Vasa was so well-preserved was not just that the shipworm that normally devours wooden ships was absent but also that the water of Stockholms ström was heavily polluted until the late 20th century.
Vasa erakordselt hea säilimise põhjuseks pole mitte ainult laevausside puudumine tema uppumiskohas vaid ka asjaolu, et Stockholmi vool oli 20. sajandi lõpuni erakordselt reostunud.