After the Vasa sank, the upper parts of her three masts with their rigging were still visible which must have made for a somewhat eerie sight.
I was suprised to learn that attempts to raise the Vasa were made immediately after she went down. The unfortunate captain Söfring Hansson was tasked with coordinating the effort. He'd likely have been grateful for the chance to sort the mess before King Gustav Adolf came visiting in a mood as foul as the letters he had written. "Sorry, your Majesty, she got a bit wet, but we'll give her a brush up and she'll be as good as new, I promise," would have sounded nicer than pointing at the slanted mast tops in the harbour. "There she lies."
Salvaging technology in the 17th century worked like this: Two ships, often just hulks, were placed on both sides of the sunken ship. A number of ropes were sent down and hooked to the ship with the help of special anchors. I could not find details about the process but it may have involved freedivers - we'll later see that those could reach the ground where the Vasa lay. The hulks were then filled with as much water as was safe for them to hold so they would lie deep in the water, the ropes tightened and the water pumped out. When the hulks or ships rose again, they would take the sunken ship up with them. The process was repeated until the wreck could have been transported to shallower waters and then further until she was fully raised above water level. At this early stage, the timber of the Vasa was not yet waterlogged, so the method might have worked.
The first attempt was made by the English engineer Ian Bulmer who succeeded in righting the ship which had sunk sideways; an important first step. But it turned out the Vasa got stuck deeper in the mud by the process, which would cause problems. Mud sucks and increased the weight that pulled on the ship to a point that could not be overcome by 17th century technology. Bulmer's successors, first a Dutch and later a Scottish engineer (1), had no more luck in lifting the Vasa, though they used the largest warships of the fleet for leverage and had extra strong anchors forged to attach to the wreck. In 1640, she was counted as lost.
Some 300 years later, the mud filling parts of the ship turned out to have one advantage; it preserved organic material which is normally lost to decay.
But some parts could still be salvaged. The top- and topgallant yards and crow’s nests had already been taken down in fall 1628, so they would not be harmed by the ice. Since King Gustav Adolf came back to Stockholm as late as December, the only part still visible were the bare tops of the masts. Later parts of the cordage and spars were brought up; those were valuable goods that could be reused. Some of the decorative figures were also saved.
Even more valuable were the cannons which were recovered with the help of a diving bell in 1663-65. The greatest disadvantage of freediving is the short time people can actually work under water because of the way down and back up (in case of the Vasa that was about 30 metres). The time would never be enough to deal with the heavy and unwieldy guns.
A diving bell is weighted so that the air compresses when the bell is let down, and the divers can go back in and take a fresh lungful several times before the bell has to be lifted, thus strechting the working time under water considerably (2). In the Baltic Sea, the cold proved more of a problem; the divers had to go up and get warm again after 15-20 minutes.
The idea of a diving bell goes back to Aristotle, but the technology was refined only in the 17th century. The bell used with the Vasa was a so-called wet bell with an open bottom of about 130 cm height. A small leaden bench – more or less an extended clapper - was attached so it stuck out 50 cm below the bell, where the diver could sit on the way up and down with his head and shoulders in the air bubble. The bell was moved by several men with help of a simple crane. The diver could also bring objects to the surface, though in case of the cannons, ropes were attached to bring them up independant of the bell (see below).
Albrecht of Treileben was a nobleman from Brandenburg in Germany who had participated in the Thirty Years War as officer in the Swedish army. He later traveled around Europe and took up scientific studies. In the 1650ies Treileben and his German associate Andreas Peckell established a dyking crew with divers from Sweden and Finland in Gothenburg which successfully salvaged parts of another ship in presence of the Lord High Steward Per Brahe. Treileben applied to King Karl X Gustav for the right to salvage parts of the Vasa (3) in 1658, but it would take until the regency of Brahe (for the underage Karl XI; 4) for Treileben to get the commission (1603).
The Italian priest, natural scientist, and traveler Francesco Negri (1624 -1698) left an eyewitness account of the salvaging in his Viaggio Settentrionale that led him as far as the North Cape. We owe him the description of the bell and some information he obtained from one of the divers. Visibility under water was acceptable; the air in the bell would have been enough for half an hour, but the cold was the greatest problem albeit the divers wore special suits of oiled leather.
the three remaining cannons salvaged in the 20th century
The weather deck was dismantled in parts to get at the cannons of the upper gun deck, but salvaging the ones from the lower gun deck proved more tricky. The team used big gripper tongs maneouvered by ropes from the crane that also worked the diving bell. The diver would fix the claws of the tong to the shaft of the cannon. The ropes leading to the surface put pressure on the thong, the claws tightened, and the cannon could be dragged out of its port, probably with some guidance by the divers. It seemed to have been a pretty smooth process since the gun ports show very little damage. Pity they didn’t use the same method for the upper gun deck.
The work was overshadowed by a big quarrel between Treileben and his associate Peckell. Treileben had Peckell forcefully emitted from the docks and kept all his tools. Treileben obviously wanted to be the only one to gain the financial win, and because he had friends in the Royal Council, he thought he’d get away with it. But Peckell managed to get a trial which condemned Treileben to pay Peckell his share and reparation for the confiscated tools (5).
The guns were sold to Lübeck and Hamburg (6), the main markets for cannons. Some of them were then sold to the Danish army which was at war with Sweden - yet again - during the Scanian War (1675-79). Denmark wanted Scania which it had to cede to Sweden in the Treaty of Roskilde in 1160. Sweden lost at sea, Denmark at land, and in the end nothing much changed (7).
The Baltic Sea has one advantage: the water is too brackish for the nasty naval ship worm Teredo navalis (8) to thrive, therefore wood survives pretty well. But nevertheless, the wreck of the Vasa was subjected to erosion and decomposition during the more than 300 years it lay in Stockholm’s harbor. Fortunately, the hull was held together by wooden nails and thus remained intact, contrary to the thousands of iron bolts that fixed most exterior structures like the beakhead, the quarter galleries, and the decorative figures. Those eroded pretty fast so that the parts fell into the mud – which proved a good thing since the mud conserved the timber so well that traces of the original colours and gilding can still be found.
The surface of the hull eroded to some extent, but never so badly that the wreck was in danger of collapsing. The worst damage here was done by the recovering of the cannons on the upper deck. Treileben also salvaged some 30 cartloads of timber which likely included the - still missing - figures, intact planks and parts of the standing rigging. In the 19th century, at least one ship anchored above the Vasa; the anchor destroyed part of the quarterdeck.
The Vasa was never entirely forgotten, but since there was no way to raise the ship before new technologies were developed in the 1950ies, she gained little interest. That changed when the Vasa was rediscovered in August 1956 by the engineer and wreck researcher Anders Franzén and the diver Per Edvin Fälting. The navy, the National Maritime Museum, and the Neptune salvage company cooperated in the huge undertaking of raising her.
The method was not so very different from the one used in 1628, but instead of hooks and anchors, six steel cables were put under the ship. Tunnels were cut through the clay with the help of high pressure water jets; a dangerous work for the divers involved since the tunnels were always in danger of collapsing, or the ship might shift her position. Plus diving suits in the 1950ies looked more like space suits, including the big helmet and external air / oxygene support by a hose - surely not as pratical as modern ones. But not accidents happened during the 1300 dives necessary to dig the tunnels and fix the cables.
The cables were connected to lifting pontoons on both sides of the ship. Those work like the hulks or ships used in earlier times, but they are more powerful. The first lift was attempted in August 1959. No one knew if the hull of the ship would hold together under the pressure of getting her out of the sucking mud, but it held. The Vasa was lifted in 18 steps - each gained a meter - from 32 metres (105 foot) to 16 (52 foot) metres and transported to shallower water where it was safer for the divers to prepare her for the final lifts.
The last lift, when the structure of the hull woud no longer be supported by water, was the most tricky one. The divers cleaned out mud and debris to lighten the ship, and made the hull watertight. All holes caused by the rusted iron bolts which had fallen out were plugged, and the gun ports covered with temporary lids. The cables were replanted with even stronger ones, and the final lifts were done by hydraulic lifting pontoons.
The last steps began in April 1961, and on April 24th, the Vasa broke the surface again after 333 years. In addition to the lifting, underwater pumps were used to get the remaining water out. In early May, she was towed close to the dry dock on Beckholmen and then floated on her own keel for the first time in more than 300 years to enter the dock proper - a bit deep in the water and leaning to port, but float she did.
The Vasa was set up on a concrete pontoon, the hull supported by beams, and the water pumped out of the dock. The ship still rests on the same pontoon today after it had been towed to the new museum complete with its pontoon. The part of the museum where the keel and lower hull sit had been flooded for that purpose.
A building was erected over the ship, but it left little space between the hull and the walk for the visitors. I've been there in 1980 during my fist visit in Sweden and I was fascinated by the Vasa even though it took a fair bit of imagination to envision her in full splendour. The new museum which opened 1990 is gives a much better impression of the ship.
Several loose parts had already been brought up during the preparations for the raising of the Vasa, and from 1963-67, the ground was systematically checked for more remains. The amount of finds on site and inside the ship amounts to 4,000 pieces. Fitting those back to their proper place on the ship proved a nice jigsaw puzzle, since there are no plans or drawings of the Vasa. Today, 95% of the wood are original timber. Loose finds like possessions of sailors and such are displayed in vitrines.
The wood needed preservation once it came in contact with air again. The wreck was sprayed with polyethylene glycol for 17 years (1962-79) until the last bit of water had been replaced so the timber woud not shrink and crack. But it turned out that the structure of the wood has nevertheless weakened during the long stay under water. The problems became visible in the 1990ies. One of the culprits turned out to be the highly corrosive iron, so all iron bolts used to reaffix the parts that had fallen off - like most of the quarterdeck and the bowsprit - since the 1960ies were replaced by stainless steel bolts. To deal with the slight shifting of the hull, adjustable steel wedges were set up to support the ship and further support structures are researched. The temperature and humidity are constantly checked and kept on a level of 18-20°C, relative humidity of 51-59 RF and UV filtered, dim light - a compromise for what is best for the ship and comfortable for visitors. Smaller, removable wooden parts are additionally treated with freeze drying under vacuum.
The Vasa is displayed as she would appear in winter storage with the three lower masts stepped and rigged. The topmast and topgallant mast as well as the upper rigging have been lost, but the new museum shows a stylised image of them outside so you can get an idea of the full hight of the ship's 52 metres. One of the few parts of timber that are not original is the mizzenmast (the original could never be found); it consists of wood left outside to season for several years.
The ropes used to rig the ship amount to 4 kilometres. The ship had four sails set when she sank, the remaining six were found in the storage rooms and could be preserved. The smallest is 32 square metres; so it would take too much space to display her with several sails set, and there's not wind to billow them prettily anyway. But the Vasa is impressive even without sails. I'm glad I had the chance to revisit her in 2012.
Footnotes
1) Willem de Besche and Alexander Forbes, respectively.
2) In modern variants, oxygen is pumped into the bell which further prolongs the time for divers to remain under water.
3) Those rights were held by Alexander Forbes at the time.
4) For the geneaology fans: Karl XI’s mother was another member of the Hostein-Gottorp family, Hedwig Eleonora. She shared in the regency with Brahe.
5) The whole process is well documented in the Royal archives. Peckell actually got more than he asked for since he only claimed the share for the time he actually worked on the site, but he got the share of the entire endeavor. Treileben had overstretched his welcome with his influential friends.
6) I wonder why they were not reused in Sweden, but the contract with Treileben meant that the Swedish government would have to buy them. There may not have been enough money.
7) The Scanian War was basically an aftermath of the Second Northern War (1658-1160). But Scania was only one battlefield during that time. France, Sweden and England were fighting the Netherlands, Brandenburg and House Austria-Hapsburg on a larger scale in the Franco-Dutch War (1672-78).
8) Teredo navalis is actually a marine bivalve mollusc, not a worm. Since the salinity of the Baltic Sea, which started out as proglacial lake 12,000 years ago, increases due to its connection with the North Sea, teredo navalis has started to create havoc in its western parts as well.
Literature
Fred Hocker, Vasa. Stockholm, 2011
Lorelei Randall,Dykarklockan – en resa i tid och rum. Online publication of the KTH Undervattensteknik, 1998
The Vasa Museum's website.
lostfort.blogspot.com
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