Vasa (ship)

Vasa (or Wasa) is a Swedish warship built 1626-1628. The ship foundered and sank after sailing ca 1,300 m into her maiden voyage on 10 August 1628. She fell into obscurity after most of her valuable bronze cannons were salvaged in the 17th century. After she was located again in the late 1950s in a busy shipping lane just outside the Stockholm harbor, she was salvaged with a largely intact hull in 1961. She was housed in a temporary museum called Wasavarvet ("The Wasa Shipyard") until 1987 and then moved to the Vasa Museum in Stockholm. The ship is one of Sweden's most popular tourist attractions and has been seen by over 29 million visitors since 1961. Vasa has since her recovery become a widely recognized symbol of the Swedish "great power period". She is today also a de facto standard in the media and among Swedes for evaluating the historical importance of shipwrecks.

Vasa was built top-heavy and had insufficient ballast. Despite an obvious lack of stability in port, she was allowed to set sail and foundered only a few minutes after she first encountered a wind stronger than a breeze. The impulsive move to set sail was the result of a combination of factors: Swedish king Gustavus Adolphus, who was leading the army on the continent on the date of her maiden voyage, was impatient to see her join the Baltic fleet in the Thirty Years' War; at the same time, the king's subordinates lacked the political courage to discuss the ship's structural problems frankly or to have the maiden voyage postponed. An inquiry was organized by the Swedish privy council to find personal responsibility for the disaster, but in the end no one was punished for the fiasco.

During the 1961 recovery, thousands of artifacts and the remains of at least 15 people were found in and around the hull of the Vasa by marine archaeologists. Among the many items found were clothing, weapons, cannons, tools, coins, cutlery, food, drink and six of the ten sails. The artifacts and the ship herself have provided historians with invaluable insight into details of naval warfare, shipbuilding techniques and everyday life in early 17th-century Sweden. Vasa was intended to express the expansionist aspirations of Sweden and to glorify king Gustavus Adolphus. No expense was spared in decorating and equipping the Vasa, which was also one of the largest and most heavily armed warships of its time.

Historical background
During the 17th century, Sweden went from being a small, poor, and peripheral northern European kingdom of little influence to one of the major powers in continental politics. Between 1611 and 1718 it was the most dominant power in the Baltic, eventually gaining territory that encompassed the Baltic on all sides. This rise to prominence in international affairs and increase in military prowess, called stormaktstiden ("age of greatness" or "great power period"), was made possible by a succession of able monarchs and the establishment of a powerful centralized government, supporting a highly efficient military organization. Swedish historians have described this as one of the more extreme examples of an early modern state using almost all of its available resources to wage war; the small northern kingdom transformed itself into a fiscal-military state and one of the most militarized states in history.

Gustavus Adolphus (1594–1632) has been considered one of the most successful Swedish kings in terms of success in warfare. When Vasa was built, he had been in power for more than a decade. The navy was in poor shape and Sweden was embroiled in a war with Poland, and looked apprehensively at the development of the Thirty Years' War in present day Germany. The war had been raging since 1618 and from a Protestant perspective it was not successful. The king's plans for a Polish campaign and for securing Sweden's interests required a strong naval presence in the Baltic.

The navy suffered several severe setbacks during the 1620s. In 1625, a squadron cruising off the Bay of Riga was caught in a storm and ten ships ran aground and were wrecked. In the Battle of Oliwa in 1627, a Swedish squadron was outmaneuvered and defeated by a larger Polish force and two large ships were lost. Tigern ("The Tiger"), which was the Swedish admiral's flagship, was captured by the Poles, and Solen ("The Sun") was blown up by her own crew when she was boarded and near capture. In 1628, three more large ships were lost in less than a month; Admiral Klas Fleming's flagship Kristina was wrecked in a storm in the Gulf of Danzig, Riksnyckeln ("Key of the Realm") ran aground at Viksten in the southern archipelago of Stockholm and, perhaps most inopportunely for the Swedish crown, Vasa foundered on her maiden voyage. Gustavus Adolphus was engaged in naval warfare on several fronts, which further exacerbated the difficulties of the navy. In addition to battling the Polish navy, the Swedes were threatened by Catholic forces that had invaded Jutland. The Swedish king had little sympathy for the Danish king, Christian IV, and Denmark and Sweden had been bitter enemies for well over a century. However, Sweden feared a Catholic conquest of Copenhagen and Zealand (Denmark). This would have granted the Catholic powers control over the strategic passages between the Baltic Sea and the North Sea, which would be disastrous for Swedish interests.

Until the early 17th century, the Swedish navy was composed primarily of smaller single-decker ships with relatively light guns; these ships were cheaper than larger ships and were well-suited for escort and patrol. For both tactical and economic reasons, the single-deckers were more suited to the Baltic environment, and were generally favored by the privy council and senior officers. However, a fleet of large ships was considered a bold statement and an effective way to impose respect on enemies and allies alike, possibly even beyond the Baltic. For the ambitious Gustavus Adolphus, a navy with a core of powerful capital ships was an opportunity that could not be missed. Vasa was the first in a series of five ships intended to be among the heaviest and most splendid of their time. The four other ships, Äpplet, Kronan, Scepter and Göta Ark, were successful and formed the backbone of the Swedish navy until the 1660s. Of these so-called regalskepp (usually translated as "royal ships"), Vasa was meant to be the grandest. The second of the large ships, Äpplet ("The Apple"; the Swedish term for the globus cruciger), was built simultaneously with Vasa. The only difference between the design of the Vasa and her sister ship: the Äpplet was a mere 1.5 meters (5 ft) wider.

Construction
Shortly before Vasa was ordered, work at the Stockholm shipyard was led by Antonius Monier, with Dutch-born Henrik Hybertsson as hired shipbuilder. On 16 January 1625, Henrik and his brother, Arendt Hybertsson (de Groote), took over the shipyard and soon signed a contract to build four ships, two larger with a keel of around 41 meters (135 ft) and two smaller of 33 meters (108 feet).

After a few years, the shipyard ran into economic problems, delaying the construction of the contracted ships. At the same time, the Swedish navy lost 10 ships in a single storm, and the king sent a worried letter to Admiral Klas Fleming, asking him to make sure that Henrik hurried the construction of the two smaller ships. Along with the letter, the king sent measurements for the ship, which was to have a keel of 37 meters (120 ft). That gave Henrik Hybertsson new problems, because the measurements ordered by the king fell between those of the larger and smaller vessels in the original contract, and the timber had already been cut. In a new letter, on 22 February 1626, the king again demanded that his measurements for the new ship be followed. Hybertsson never saw Vasa completed; he fell ill in late 1625, one year into construction, and died in the spring of 1627. The supervision of the shipbuilding was given to Hybertsson's assistant, Henrik 'Hein' Jacobsson, also a Dutch immigrant.

Vasa's hull was complete enough to be launched in 1627, probably during the spring. After this, work most likely began on finishing the upper deck, the sterncastle, the beakhead and the rigging. Sweden had still not developed a sizeable sailcloth industry, and material had to be ordered from abroad, some from France but also from Germany and the Low Countries. The sails were made mostly of hemp and partly of flax. The rigging was made entirely of hemp imported from Latvia through Riga. The king visited the shipyard in January 1628 and made what was probably his only visit aboard the ship.

In the summer of 1628, the captain responsible for supervising construction of the ship, Söfring Hansson, arranged for the ship’s stability to be demonstrated for the Vice Admiral responsible for procurement, Klas Fleming, who had recently arrived in Stockholm from Prussia. Thirty men ran back and forth across the upper deck to start the ship rolling, but the admiral stopped the test after they had made only three trips, as he feared the ship would capsize. According to testimony by the ship’s master, Göran Mattson, Fleming remarked that he wished the king were at home. Gustavus Adolphus had been sending a steady stream of letters insisting that the ship put to sea as soon as possible.

There has been much speculation that Vasa was lengthened during construction and whether an additional gun deck was added late during the build or not. Little evidence suggests that Vasa was substantially modified after the keel was laid. Ships contemporary to Vasa that were elongated were cut in half and new timbers spliced between the existing sections, making the addition readily identifiable, but no such addition can be identified in the hull. Claims about the addition of a second gun deck are harder to refute, but significant evidence exists against it. The king ordered 72 24-pound cannons for the ship on 5 August 1626, and this was too many to fit on a single gun deck. Since the king's order was issued less than five months after construction started, it would have come early enough for the second deck to be included in the design. The French Galion du Guise, the ship used as a model for Vasa, according to Arendt Hybertsson, also had two gun decks. Laser measurements of Vasa's structure conducted 2007-2011 confirmed that no major changes were implemented during construction, but that the center of gravity was too high.

Vasa was one of the earliest examples of a warship with two full gun decks, and was built when the theoretic principles of shipbuilding were still poorly understood. The safety margins at the time were also far below anything that would be acceptable today. Combined with the fact that 17th century warships were built with intentionally high superstructures (to be used as firing platforms), this made the Vasa a risky undertaking.

Armament
Vasa was built during a time of transition in naval tactics, from an era when boarding was still one of the primary ways of fighting enemy ships to an era of the strictly organized ship-of-the-line and a focus on victory through superior firepower. Vasa was armed with powerful guns and built with a high stern, which would act as a firing platform in boarding actions for some of the 300 soldiers she was supposed to carry. She was neither the largest ship ever built, nor the one carrying the greatest number of guns. What made her arguably the most powerful warship of the time was the combined weight of shot that could be fired from the cannon of one side: 588 pounds (267 kg). This was the largest concentration of artillery in a single warship at the time, and it was not until the 1630s that a ship with more firepower was built. This large amount of naval artillery was placed on a ship that was quite small relative to the armament carried. By comparison USS Constitution, a famous Napoleonic era frigate built 169 years after Vasa, had roughly the same firepower, but was over 700 tonnes heavier.

The Constitution, however, belonged to a later era of naval warfare that employed the line of battle-tactic, where ships fought in single file (or line ahead) while the group as a whole attempted to present the batteries of one side toward the enemy. The guns would be aimed in the same direction and fire almost simultaneously. In the 17th century, tactics involving organized formations of several ships had still not been developed. Rather, ships would fight individually or in improvised groups, and focused on boarding. Vasa, though possessing a formidable battery, was built with these tactics in mind, and therefore lacked a unified broadside with guns that were all aimed in roughly the same direction. Rather, the guns were intended to be fired independently and were arranged according to the curvature of the hull, meaning that the ship would be bristled with artillery in all directions, covering virtually all angles except straight forward and partial, backwards-facing radii about 45 degrees to either side of the stern.

Naval gunnery in the 17th century was still in its infancy. Guns were expensive and had a much longer lifespan than any warship. Guns with a lifetime of almost a century were not unheard of, while most warships would be used for only 15 to 20 years. In Sweden and many other European countries, a ship would normally not "own" its guns, but would be issued armament from the armory for every mission. Ships were therefore usually fitted with guns of very diverse age and size. What allowed Vasa to carry so much firepower was not merely that an unusually large number of guns were crammed into a relatively small ship, but also that the 46 main 24-pounder guns were of a new and standardized lightweight design. Two additional 24-pounders, of a heavier and older design, were intended to go in the bows, the so-called bow chasers. All cannons during this time had to be made from individually made casts that could not be reused, but Vasa's guns had such uniform precision in their design that their primary dimensions varied by only a few millimeters, and their bores were almost exactly 146 millimeters (5.7 in). The remaining armament of Vasa consisted of eight 3-pounders, six large caliber howitzers for use during boarding actions, and two 1-pound falconets. Also included on board were 894 kilograms (1,970 lb) of gunpowder and various types of shot for the guns.

Ornamentation
As was the custom with warships at the time, Vasa was decorated with sculptures intended to glorify the authority, wisdom and martial prowess of the monarch and also to deride, taunt and intimidate the enemy. The sculptures made up a considerable part of the effort and cost of building the ship and even added considerably to its weight, thereby hampering its maneuverability. The symbolism used in decorating the ship was mostly based on the Renaissance idealization of Roman and Greek antiquity, which had been imported from Italy through German and Dutch artists. Imagery borrowed from Mediterranean antiquity dominates the motifs, but also include figures from the Old Testament and even a few from ancient Egypt. Many of the figures are in Dutch grotesque style, depicting fantastic and frightening creatures, including mermaids, wild men, sea monsters and tritons. The decoration inside the ship is much sparser and is largely confined to the officers' quarters and the admiral's cabin, both of which are in the stern.

Residues of paint have been found on many sculptures and on other parts of the ship. The entire ornamentation was once painted in vivid colors. The sides of the beakhead (the protruding structure below the bowsprit), the bulwarks (the protective railing around the weather deck), the roofs of the quarter galleries, and the background of the transom (the flat surface at the stern of the ship) were all painted red, while the sculptures were decorated in bright colors, and the dazzling effect of these was in some places reinforced with patches of gold leaf. Previously, it was believed that the background color had been blue and that all sculptures had been almost entirely gilded, and this is reflected in many paintings of Vasa from the 1970s to the early '90s, such as the lively and dramatic drawings of Björn Landström or the painting by Francis Smitheman. In the late 1990s, this view was revised and the colors are properly reflected in more recent reproductions of the ship's decoration by maritime painter Tim Thompson and the 1:10 scale model in the museum. Vasa is an example not so much of the heavily gilded sculptures of early Baroque art but rather "the last gasps of the medieval sculpture tradition" with its fondness for gaudy colors, in a style that today would be considered kitsch.

The sculptures are carved out of oak, pine or linden, and many of the larger pieces, like the huge 3-meter (10 ft) long figurehead lion, consist of several parts carved individually and fitted together with bolts. Close to 500 sculptures, most of which are concentrated on the high stern and its galleries and on the beakhead, are found on the ship. The figure of Hercules appears as a pair of pendants, one younger and one older, on each side of the lower stern galleries; the pendants depict opposite aspects of the ancient hero, who was extremely popular during antiquity as well as in 17th-century European art. On the transom are biblical and nationalistic symbols and images. A particularly popular motif is the lion, which can be found as the mascarons originally fitted on the insides of the gunport doors, grasping the royal coat of arms on either side, the figurehead, and even clinging to the top of the rudder. Each side of the beakhead originally had 20 figures (though only 19 have actually been found) that depicted Roman emperors from Tiberius to Septimius Severus. Overall, almost all heroic and positive imagery is directly or indirectly identified with the king and was originally intended to glorify him as an absolute and flawless ruler. The only actual portrait of the king, however, is located at the very top of the transom in the stern. Here he is depicted as a young boy with long, flowing hair, being crowned by two griffins representing the king's father, Charles IX.

A team of at least six expert sculptors worked for a minimum of two years on the sculptures, most likely with the assistance of an unknown number of apprentices and assistants. No direct credit for any of the sculptures has been provided, but the distinct style of one of the most senior artists, Mårten Redtmer, is clearly identifiable. Other accomplished artists, like Hans Clausink, Johan Didrichson Tijsen (or Thessen in Swedish) and possibly Marcus Ledens, are known to have been employed for extensive work at the naval yards at the time Vasa was built, but their respective styles are not distinct enough to associate them directly with any specific sculptures.

The artistic quality of the sculptures varies considerably, and about four distinct styles can be identified. The only artist who has been positively associated with various sculptures is that of Mårten Redtmer, whose style has been described as "powerful, lively and naturalistic" and was responsible for a considerable percentage of the sculptures. These include some of the most important and prestigious pieces: the figurehead lion, the royal coat of arms, and the sculpture of the king at the top of the transom. Two of the other styles are described as "elegant ... a little stereotyped and manneristic", and of a "heavy, leisurely but nevertheless rich and lively style", respectively. The fourth and last style, deemed clearly inferior to the other three, is described as "stiff and ungainly" and was done by other carvers, perhaps even apprentices, of lesser skill.

Maiden voyage
On 10 August 1628, Captain Söfring Hansson ordered Vasa to set sail on her maiden voyage to the naval station at Älvsnabben. The day was calm, and the only wind was a light breeze from the southwest. The ship was towed along the waterfront to the southern side of the harbor, where three sails were set, and the ship made way to the east. The gun ports were open, and the guns were out to fire a salute as the ship left Stockholm.

After Vasa emerged from the lee of the city, a gust of wind filled her sails, and she heeled suddenly to port. The sheets were cast off, and the ship slowly righted herself as the gust passed. Soon another gust came, which again forced the ship onto its port side, this time pushing the open lower gun ports under water, causing water to rush in on the lower gun deck. The inflow of water heeled Vasa over further, and she quickly sank to a depth of 32 meters (105 ft) only 120 meters (390 ft) from shore. Survivors clung to debris to save themselves, and many nearby boats rushed to their aid, but despite these efforts and the short distance to land, 30 to 50 people perished with the ship, according to reports. The flags and the tops of the main and fore masts, still visible above the surface, leaned heavily to port because of ballast that had shifted during the sinking. Vasa sank in full view of a crowd of hundreds, if not thousands, of mostly ordinary Stockholmers who had come to see the great ship set sail. The crowd included foreign ambassadors, in effect spies of Gustavus Adolphus' allies and enemies, who also witnessed the catastrophe.

Inquest
The king was notified by letter of Vasa's fate on 27 August. "Imprudence and negligence" must have been the cause, he wrote angrily in his reply, demanding in no uncertain terms that the guilty parties be punished. Captain Söfring Hansson, who survived the disaster, was immediately imprisoned awaiting trial. Under initial interrogation, he swore that the guns had been properly secured and that the crew was sober. A full inquest, organized by a committee, many members of which were also on the privy council, took place before a court of admirals and councilors on 5 September 1628. Each of the surviving officers was questioned as was the supervising shipwright and a number of expert witnesses. Also present at the inquest was the Admiral of the Realm. The object of the inquest was as much or more to find a scapegoat as to find out why the ship had sunk. Whoever the committee might find guilty for the fiasco would face a severe penalty.

Surviving crew members were questioned one by one about the handling of the ship at the time of the disaster. Was it rigged properly for the wind? Was the crew sober? Was the ballast properly stowed? Were the guns properly secured? However, no one was prepared to take the blame. Crewmen and contractors formed two camps; each tried to blame the other, and everyone swore he had done his duty without fault and it was during the inquest that the details of the hushed-up stability test were revealed. Nevertheless, the answers were deemed satisfactory, and no incriminating evidence was found.

Later, the focus was turned on the ship builders. "Why did you build the ship so narrow, so badly and without enough bottom that it capsized?" the shipwright Jacobsson was asked by the investigators. He fell back on the classic strategy of civil servants; he had simply followed orders. Jacobsson stated that he built the ship as directed by Henrik Hybertsson (long since dead and buried), who in turn had followed the instructions of the king. Jacobsson had in fact widened the ship by 42 centimeters (1.38 ft) after taking over the construction, but the ship's construction was too far along to allow further widening.

In the end, no guilty party could be found. The answer Arendt Hybertsson gave when asked by the court why the ship sank was "only God knows". Gustavus Adolphus had approved all measurements and armaments, and the ship was built according to the instructions and loaded with the number of guns specified. In the end, no one was punished or found guilty for negligence, and the sinking was explained as an act of God. The sinking of Vasa was a major economic disaster; the ship's cost was more than 40,000 dalers, a huge expense for the small Swedish state.

Vasa as a wreck
Less than three days after the disaster, a contract was put out for the ship to be raised. However, those efforts were unsuccessful. The earliest attempts at raising Vasa by English engineer Ian Bulmer resulted in righting the ship somewhat to starboard but also got it more securely stuck in the mud and was most likely one of the biggest impediments to the earliest attempts at recovery. Salvaging technology in the early 17th century was much more primitive than today, but the recovery of ships used roughly the same principles as were used to raise Vasa more than 300 years later. Two ships or hulks were placed parallel to either side above the wreck, and ropes attached to several anchors were sent down and hooked to the ship. The two hulks were filled with as much water as was safe, the ropes tightened, and the water pumped out. The sunken ship then rose with the ships on the surface and could be towed to shallower waters. The process was then repeated until the entire ship was successfully raised above water level. Even if the underwater weight of Vasa was not great, the mud in which it had settled made it sit more secure on the bottom and required considerable lifting power to overcome. More than 30 years after the ship's sinking, in 1664, Albreckt von Treileben and Andreas Peckell mounted an effort to recover the valuable guns. With a simple diving bell, the team of Swedes and Germans retrieved more than 50 of them.

Such activity waned when it became clear that the ship could not be raised by the technology of the time. However, Vasa did not fall completely into obscurity after the recovery of the guns. The ship was mentioned in several histories of Sweden and the Swedish Navy, but the exact location of the ship and the details surrounding it varied. In 1844, the navy officer Anton Ludwig Fahnehjelm turned in a request for salvaging rights to the ship, claiming he had located it. Fahnehjelm was an inventor who designed an early form of light diving suit and had previously been involved in other salvage operations. No records exist of any major salvage attempts after Fahnehjelm filed his request, and it has been assumed that none was actually made. Recently, a map found in the Stockholm City Museum archives dated to the late 1830s marks the exact location of the ship with the word wrak ("wreck") and a dotted circle as well as detailed depth markings around the wreck site. In 1999, a witness also claimed that his father, a petty officer in the Swedish navy, had partaken in diving exercises down to Vasa in the 1920s.

Deterioration
In the 333 years that Vasa lay on the bottom of Stockholms ström, the ship and its contents were subject to several destructive forces, first among which were decomposition and erosion. Among the first things to decompose were the thousands of iron bolts that held the beakhead and much of the sterncastle in place, and this included all of the ship's wooden sculptures. Almost all of the iron on the ship rusted away within a few years of the sinking, and of the large iron objects like ammunition and cannons almost nothing remained but carbon. This helped preserve the shape of many metal objects, though the actual metal content was negligible. Of the human remains, the soft tissue was quickly consumed by bacteria, fish and crustaceans, leaving only the bones, which were often held together only by clothing. Clothing and leather objects, such as pouches and shoes, were badly worn, but many survived until recovered in the 20th century.

The entire sterncastle, the high, aft portion of the ship that housed the officers' quarters and held up the transom, gradually collapsed into the mud with all the decorative sculptures, and all but minute traces of the paint and gold leaf on the sculptures disappeared. The quarter galleries, which were merely nailed to the sides of the sterncastle, soon collapsed and were found lying almost directly below their original locations. Many of the wooden elements were also worn by the currents and by the flow of mud sediments, and some sculptural elements were worn so badly that they were only barely recognizable as carvings when recovered.

In addition to deterioration caused by natural forces, the ship suffered many instances of mechanical damage caused by human activity. The more or less successful salvage operations from 1629 to the 1680s had considerable impact on the ship's structure. To recover the cannons, Peckell and Treileben had broken up and removed much of the planking of the weather deck to get to the cannons on the decks below. Peckell also reported that he had recovered 30 cartloads of wood from the ship; these might have included not just planking and structural details but also some of the sculptures which today are missing, such as the life-size Roman warrior near the bow and the sculpture of Septimius Severus that adorned the port side of the beakhead. Since Vasa lay in a busy shipping channel, tons of slag and blasting rubble were dumped on the ship in the 19th century; this caused further collapse of the sterncastle and most of the weather deck. Traces of numerous anchors that had caught on the ship and then wrenched loose by force became evident during the modern excavations.

Vasa rediscovered
In the early 1950s, amateur archaeologist Anders Franzén considered the possibility of recovering wrecks from the cold brackish waters of the Baltic because, he reasoned, they were free from the shipworm Teredo navalis, which usually destroys submerged wood rapidly in warmer, saltier seas. Franzén had previously been successful in locating wrecks such as Riksäpplet and Lybska Svan, and after long and exhaustive research he began looking for Vasa as well. He spent years probing the waters around the many assumed locations of the wreckage, without success. He did not succeed until he narrowed his search based on accounts of an unknown topographical anomaly just south of the Gustav V dock on Beckholmen. In 1956, with a home-made, gravity-powered coring probe, he located a large wooden object almost parallel to the mouth of the dock on Beckholmen. The location of the ship received considerable attention, even if the identification of the ship could not be determined without closer investigation. Soon after the announcement of the find, plans were made to determine how to excavate and raise Vasa. The Swedish Navy was involved from the start, as were various museums and the National Heritage board, representatives of which eventually formed the Vasa Committee, the predecessor of the Vasa Board.

Recovery
The wreck was lifted in a relatively straightforward way by digging six tunnels under the hull through which steel cables were attached to a pair of lifting pontoons. The work under the ship was extremely dangerous, requiring the divers to dig by flushing out mud with water sprayed through a nozzle under high pressure. Visibility was practically zero most of the time, and only a few meters in the best of conditions. A persisting risk was that the wreck could shift or settle deeper into the mud while a diver was working in a tunnel, trapping him underneath the wreckage. The almost vertical sections of the tunnels near the side of the hull could also potentially collapse and bury a diver inside. Despite the dangerous conditions, more than 1,300 dives were employed in the salvage operation without any serious accidents.

The ship was raised in a series of 18 lifts in August and September 1959, bringing it from a depth of 32 meters (105 ft) to a more easily managed 16 meters (52 ft) in the more sheltered area of Kastellholmsviken, where it was prepared for the final lift during a year and a half. Debris and mud were cleared from the upper decks to lighten it, and it was made as watertight as possible. The gun ports were closed by means of temporary lids; a temporary replacement of the collapsed sterncastle was constructed, and all the holes from the iron bolts that had rusted away were plugged. The first lift began on 8 April 1961, and on the morning of 24 April, Vasa was ready to break the surface for the first time in 333 years. Press from all over the world, television cameras, 400 invited guests on barges and boats, and thousands of spectators on shore watched as the first timbers broke the surface. The ship was then emptied of water and mud, caulked and plugged up, and then towed to the Gustav V dry dock on Beckholmen, where she was placed on a concrete pontoon which still is the floor she rests on.

From the end of 1961 to December 1988, Vasa was housed in a temporary structure called Wasavarvet ("The Vasa Shipyard"). The building was very cramped, making it impossible to see the entire ship at once. Visitors could view the ship from just two levels, and the maximum viewing distance was only 5 m, which made it difficult for viewers to get an overall view of the ship. In 1981, the Swedish government decided that a permanent building was to be constructed, and a design competition was organized. The ground was broken in 1987, and Vasa was towed to the half-finished Vasa Museum in December 1988. The museum was officially opened to the public in 1990.

Archaeology
Vasa posed an unprecedented challenge for archaeologists. Never before had a four-story structure with most of its original contents largely undisturbed been available for excavation. The conditions under which the team had to work added to the difficulties. The ship had to be kept wet in order that it not dry out and crack before it could be properly conserved. Digging had to be performed under a constant drizzle of water and in a sludge-covered mud that could be more than one meter (approximately three feet) deep. In order to establish find locations, the hull was divided into several sections demarcated by the many structural beams, the decking and by a line drawn along the center of the ship from stern to bow. For the most part, the decks were excavated individually, though at times work progressed on more than one deck level simultaneously.

Finds
Vasa had four preserved decks: the upper and lower gun decks, the hold and the orlop. Because of the constraints of preparing the ship for conservation, the archaeologists had to work quickly, in 13-hour shifts during the first week of excavation. The upper gun deck was greatly disturbed by interference, both from material from the collapsed decking and from contamination from the surrounding environment. Nonetheless, the upper gun deck yielded many interesting finds such as a well-preserved chest of personal belongings including a felt hat, sewing tools, a comb, two pairs of shoes, a shoe last, gloves, a schnapps keg, a wooden spoon, a number of coins and some smaller belongings. This and many of the other finds testify to the simple life of a 17th-century sailor.

Initially, many finds were cataloged in groups corresponding to the original object they had been a part of. Later, this method was expanded to count individual objects such as the staves, bottom and hoops of a barrel as separate objects. This considerably increased the already numerous finds, and the current catalog, part of which is available online, comprises well over 26,000 artifacts.

After the ship itself had been salvaged and excavated, the site was searched for artifacts where most of the roughly 700 sculptures that adorned the outside of the ship were found. The last object to be brought up was the longboat, found lying parallel to the ship and believed to have been lying on the weather deck or being towed by Vasa when she sank.

Many more recent objects contaminating the site were disregarded when the finds were registered. Among the more infamous contaminations was a statue of 20th century Finnish runner Paavo Nurmi, which was placed on the ship as a prank by students of Helsinki University of Technology just days before the final lift.

Causes of sinking
In the 17th century, the design requirements and calculations for building a ship existed only in the head of the shipwright. Scientific theories on vessel design or stability had not yet been developed, so important factors like the ship's center of gravity had to be estimated from the builder's experience. The hull of Vasa was divided into three decks and a bottom compartment containing the ballast, which consisted of large, tightly packed stones. Upon salvaging, the ship was found to have an intact hold full of ballast stones. Vasa carried 120 tonnes of ballast, but this was not enough to counter her considerable weight above the water line; even a light squall would have seriously destabilized the ship. Common practice of the time dictated that heavy guns were to be placed on the lower gun deck to decrease the weight on the upper gun deck and improve stability. The armament plans were changed many times during the build either to place 24-pounders on the lower deck along with lighter 12-pounders on the upper deck or to place 24-pounders on both decks. The gun ports on the upper deck were in fact the correct size for 12-pounders, but in the end the ship was finished with the heavy 24-pounders on both decks, and this may have contributed to poor stability.

Warships of the period, even when properly armed, were highly unstable. A major reason for this was that they were built with high aftercastles to provide a platform for soldiers to fire upon the enemy with small arms. Also, Vasa may have had the additional problem of an upper hull built with thick wale planks that were much too heavy. This might have occurred because of inexperience with two-decker ships or because of the possibility of adding even heavier armaments in the future. However, nothing is inherently wrong with the hull form of the ship; it is within the norms of the period. Later designs, for example English ships of equivalent firepower developed after Vasa, used their heaviest guns on the lower decks and lighter ones on any upper decks, where extra weight was most likely to be detrimental to stability and the righting moment of the ship. Inwardly curved topsides, so-called tumblehome, were also more pronounced on later designs, so as to bring the mass of the guns closer to the center line of the ship, thus increasing stability.

Captain Söfring Hansson sailed the new ship with open gun ports, which was uncommon. Usually, a brand new ship sailed first with closed gun ports to give the captain and crew an idea of how it would handle, as each ship built in the 17th century handled a little differently from every other ship. This decision allowed water entry through the gun ports when they dipped below the waterline, and the weight of the water caused the boat to stop righting and capsize. Finally, Vasa was supposed to head for Älvsnabben, the naval station in the outer archipelago, to take on all of her stores and personnel, and that might have provided more stability.

Conservation
Although Vasa was in surprisingly good condition after 333 years at the bottom of the sea, it would have quickly deteriorated if the hull had been simply allowed to dry. The large bulk of Vasa, over 900 cubic meters (32,000 cu ft) of oak timber, constituted an unprecedented conservation problem. After some debate on how to best preserve the ship, conservation was done using polyethylene glycol (PEG), a method that was also used years later in the conservation process of the 16th-century English ship Mary Rose. Vasa was sprayed with this glycol for 17 years, followed by 9 years of slow drying.

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. The highly toxic and hostile environment meant that even the toughest microorganisms that break down wood had difficulty surviving. This, along with the fact that Vasa had been newly built when she sank, contributed to her conservation. Unfortunately, the toxicity of the water also had a negative effect. The sulfides present in the porewater of the sediments around Vasa had penetrated the wood, and when the ship was salvaged, and exposed to air after about 300 years of immersion in oxygen-depleted water, it began reacting with atmospheric oxygen. After exhumation in 1961 from the protective anoxic water, sulfide oxidation produced sulfuric acid. In the autumn of 2000, spots of white residue from only a few centimeters to half a meter (c. 3 to 20 in) were noticed on Vasa. These turned out to be sulfate-containing salts that had formed on the surface of the wood when the sulfides reacted with atmospheric oxygen. The stains had a very low pH and were the first indications that the ship contained considerable amounts of sulfuric acid. The salts on the surface of Vasa and objects found in and around it are not a threat themselves (even if the discoloring may be distracting), but if they are from inside the wood, they may expand and crack the planking from inside. This would cause particularly serious damage if it happened to objects made by skilled craftsmen, such as household items or some of the hundreds of carved sculptures. As of 2002, the amount of sulfuric acid in Vasa's hull was estimated to be more than 2 tonnes, and more is continually being created. Enough sulfides are present in the ship to produce another 5000 kg of acid at a rate of about 100 kg per year; this might eventually destroy the ship almost entirely.

While most of the scientific community considers that the destructive substance responsible for Vasa's long-term decay is sulfuric acid, Ulla Westermark, professor of wood technology at Luleå University of Technology, has proposed another mechanism with her colleague Börje Stenberg. Experiments done by Japanese researchers show that treating wood with PEG in an acidic environment can generate formic acid and eventually liquify the wood. Vasa was exposed to acidic water for more than three centuries, and therefore has a relatively low pH. Samples taken from the ship indicate that formic acid is present, and that it could be one of the multiple causes of a suddenly accelerated rate of decomposition.

The museum is constantly monitoring the ship for damage caused by decay or warping of the wood. Ongoing research seeks the best way to preserve the ship for future generations and to analyze the existing material as closely as possible. A current problem is that the old oak of which the ship is built is starting to give way, and the braces that support it are pressed deeper into the hull every year. "The amount of movement in the hull is worrying. If nothing is done, the ship will most likely capsize again", states Magnus Olofson from the Vasa Museum. An effort to secure Vasa for the future is under way, in cooperation with the Royal Institute of Technology, Texas A&M University and other institutions around the globe.

To deal with the problem of the inevitable deterioration of the ship, the main hall of the Vasa Museum is kept at a temperature of 18 – and a humidity level of 55%. To slow the destruction by sulfuric acid, different methods have been tried. Small objects have been sealed in plastic containers filled with an inert atmosphere of nitrogen gas, for halting further reactions between sulfides and oxygen. The ship itself has been treated with cloth saturated in a basic liquid to neutralize the low pH, but this is only a temporary solution as acid is continuously produced. The original bolts rusted away after the ship sank but were replaced with modern ones that were galvanized and covered with epoxy resin. Despite this, the new bolts have also started to rust and are releasing iron into the wood, which accelerates the deterioration. Plans call for new bolts made from materials that are non-reactive, such as titanium, carbon fiber or fiberglass.

Legacy
Vasa has become a popular and widely recognized symbol for a historical narrative about the Swedish stormaktstiden ("the Great Power-period") in the 17th century, and about the early development of a European nation state. Within the disciplines of history and maritime archaeology the wrecks of large warships from the 16th, 17th and 18th centuries have received particularly widespread attention as perceived symbols of a past greatness of the state of Sweden. Among these wrecks, Vasa is the single most well-known example, and has also become recognized internationally, not least through a deliberate use of the ship as a symbol for marketing Sweden abroad. The name Vasa has in Sweden become synonymous with sunken vessels that are considered to be of great historical importance, and these are usually described, explained and valued in relation to Vasa herelf. The Swedish maritime archaeologist Carl-Olof Cederlund, who has been active in the various Vasa-projects, has described the phenomenon as regalskepps-syndromet, "the royal ship syndrome" (after the archaic term used for the largest warships named after the regalia of the Swedish kings). He associates the "syndrome" to a nationalist aspect of the history of ideas and traditional perceptions about hero-kings and glory through war. The focus of this historical theory lies on the "great periods" in "our [Swedish] history" and shares many similarities with the nationalist views of Viking era in the Nordic countries and the praising of Greek and Roman Antiquity in the Western world in general. Cederlund has stressed the ritualized aspects of the widely publicized salvage in 1961 and has compared the modern Vasa Museum with "a temple in the Classical sense of the word". The placement of the museum on Djurgården, traditional crown property, and its focus on "the King's ship" has led him to suggest a description of it as "The Temple of the Royal Ship".

Literature and popular culture
Vasa has been the subject of hundreds of books, articles and papers on topics ranging from marine archaeology to culinary history. Three children's books about Vasa have been written in Swedish and later translated into English, German, Danish, and Norwegian: The Vasa Saga by Bertil Almqvist, The Vasa Sets Sail by Mats Wahl (illustrated by Sven Nordqvist), and The Vasa Piglet by Björn Bergenholtz.

Vasa's unique status has drawn considerable attention and captured the imagination of more than two generations of scholars, tourists, model builders, and authors. Though historically unfounded, the popular perception of the building of the ship as a botched and disorganized affair (dubbed "the Vasa-syndrome") has been used by many authors of management literature as an educational example of how not to organize a successful business.

The Vasa Museum has co-sponsored two versions of a documentary about the history and recovery of the ship, both by documentary filmmaker Anders Wahlgren. The second version is currently shown in the museum and has been released on VHS and DVD with narration in 16 languages. In late 2011, a third Vasa-film premiered on Swedish television, with a longer running time and a considerably larger budget (with over 7.5 million kronor provided by SVT). An educational computer game, now in its second generation, has been made and is used in the museum and on its website to explain the fundamentals of 17th century ship construction and stability. Several mass-produced model kits and countless custom-built models of the ship have been made. In 1991, a 308-tonne pastiche reproduction of the ship was built in Tokyo to serve as a 650-passenger sightseeing ship. Vasa has inspired many works of art, including a gilded Disney-themed parody of the pilaster sculptures on the ship's quarter galleries. Being a popular tourist attraction, Vasa is used as a motif for various souvenir products such as T-shirts, mugs, refrigerator magnets, and posters. Commercially produced replicas—such as drinking glasses, plates, spoons, and even a backgammon game—have been made from many of the objects belonging to the crew or officers found on the ship.