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Investigation of the Seabed off Björkenäs, Kalmar

Introduction

Approximately 6 km north of Kalmar lies the small headland of Björkenäs. From 1558 until the 17th century, an important naval shipyard was located here. Among the vessels built at the yard was the great warship Mars. It was also here that Elefanten was brought for repairs following a battle in 1564. However, the ship sank just southeast of the shipyard, where its remains still lie today.

Most of the former shipyard area is now occupied by private houses, and few traces of the historic yard survive on land. We therefore decided to investigate whether any remains of the shipyard have been preserved on the seabed off Björkenäs.

The Goal of the Investigation

A large wreck at the site has commonly been referred to as Finska Falken since the 1950s. To our knowledge, its identity has never been conclusively established, despite previous archival research. Moreover, several vessels in the Swedish Navy bore the same or similar names. Throughout this report, we nevertheless refer to the wreck as Finska Falken for the sake of simplicity, while acknowledging that this identification remains unconfirmed.

Several other wrecks are also known to lie off Björkenäs. The aim of this investigation was to locate Finska Falken, document the other known wrecks, and identify any additional underwater remains associated with the activities of the historic shipyard.

Figure 1, location of Björkenäs
Figure 1, location of Björkenäs
Figure 2, wrecks known to local divers in the 1950s. Sent by Bengt Bengtsson [4] who still lives next to the bay.
Figure 2, wrecks known to local divers in the 1950s. Sent by Bengt Bengtsson [4] who still lives next to the bay.
Figure 3, alternate positions of wrecks according to a picture from Robert Holm
Figure 3, alternate positions of wrecks according to a picture from Robert Holm
Figure 4, the silver necklace made by Bjerre 1951 and sold recently on Bukowskis.
Figure 4, the silver necklace made by Bjerre 1951 and sold recently on Bukowskis.
Archive Research

Within the local diving community, the wreck known as Finska Falken has been known since the 1950s. However, its exact location was unknown to us, and it was also unclear whether the site had been visited by divers in recent years.

The identification of the wreck as Finska Falken appears to originate from research conducted by the Kalmar city notary Bjerre [3], following his extensive investigations at the Swedish National Archives (Riksarkivet) and the Swedish National Maritime and Transport Museums (Sjöhistoriska museet).

Several other vessels in the Swedish Navy bore the name Finska Falken or closely related names.

One vessel named Finska Falken was built in 1631 and ran aground before sinking in the Gulf of Finland in 1651. The wreck was discovered as early as 1974, although its identity was not conclusively established until 2025. Another vessel believed to have borne the name Finska Falken was reportedly lost off Warnemünde on 11 July 1564. However, in a painting of the battle by P. C. van Soest, the vessel is identified as Svenske Falken. A wreck discovered at the site in 1994 was subsequently suggested to be that of Finska Falken [5].

Reference [6] mentions several additional vessels that may represent the same ship or different vessels. The frequent renaming of ships further complicates their identification. Among the names mentioned are Finska Falken, Viborgs Falken, Pippingen, Buffeln, and Marcolphus. Based on the information presented in this source, the identity and relationship of these vessels remain uncertain.

The conclusion is that the identity of the large wreck off Björkenäs cannot be established without a professional maritime archaeological investigation, including the collection and analysis of dendrochronological samples.

By consulting Fornsök [1] and conducting Google searches, we were able to establish the approximate location of the wreck, gather background information on Finska Falken, and identify individuals with additional knowledge whom we subsequently interviewed in person [4]. Bengt Bengtsson also provided the map shown in Figure 2, indicating the locations of four known wrecks in the bay north of Björkenäs.

Reference [3] mentions four wrecks in the vicinity of Björkenäs (five if Dansken, which lies outside the immediate study area, is included). These comprise a civilian vessel of lighter construction built of pine, two smaller wrecks of unspecified type, and Finska Falken.

Another map, shown in Figure 3, was provided by Robert Holm. It most likely originates from Dykarklubben Kalmarsund and also depicts four wrecks, although their plotted positions differ from those shown in Figure 2.

During the 1950s and 1960s, it was common for diving clubs to carry out shore-based dives in very shallow water. It is therefore reasonable to assume that most substantial archaeological remains close to the shoreline had already been discovered. However, wrecks may have been regarded as the primary objects of interest, and we have found no documented evidence of other remains associated with the shipyard apart from the four known wrecks.

The lawyer and craftsman Stig Bjerre [3] served as City Notary of Kalmar from the mid-1940s for more than three decades. He was also a dedicated diver and amateur archaeologist who published an article on Finska Falken in the newspaper Barometern in 1956 [2]. Bjerre dived on the wreck of Elefanten and was known to recover black oak from the site, which he used to make silver jewellery.

The silver necklace with oak inlays shown in Figure 4 was sold at Bukowskis in 2023. An accompanying note, written by Bjerre himself, states that the oak originated from Enighed and one of the 3 ships lost in the battle with Denmark 1611.  This might be the first indication of the identity of the wreck “Dansken”!

Reference [3] makes it clear that Bjerre’s archival research at Riksarkivet formed the basis for his identification of the large wreck north of Björkenäs as Finska Falken. As far as we have been able to determine, no other archaeologists appear to have been involved in either the investigation or the identification of the wreck.

A ship’s clerk at the Björkenäs shipyard, Mats Matsson, mention in 1566 some persephones taken care of  ”Aff Finjske Falkenn som bleff bortte wed Bijrkenes” which translates to “from Finska Falken that was lost at Björkenäs”.

Bjerre continued his research at Sjöhistoriska Muséet and found “en manshöjd” (a man’s height) of documents on Finska Falken.

Bjerre states that Finska Falken was one of King Gustav Vasa’s warships, built at Viborg and launched in 1556. The vessel was subsequently assigned to Älvsborg on Sweden’s west coast, where it remained until 1562, when increasing tensions in the Baltic once again required the presence of the fleet. It then sailed to the Baltic as part of a group of 13 ships lead by Sankt Erik; a ship built in Björkenäs by the way.

Upon arriving in Stockholm, the fleet’s inventories, including provisions, artillery, and ammunition were recorded. At that time, Finska Falken was listed as carrying twenty guns and falconets of various calibres. The following year the Northern Seven Years’ War broke out and according to information the number of guns were then doubled on Finska Falken.

In the inventory ”Inventarium ved Calmare Slotz Skipz Gårdh sampt på Skeb, Skuter och Båter sammestedtz Anno 66’ ” (meaning “inventory at Kalmar castle shipyard regarding ships and boats the year 1566”) it is mentioned that ”Wijborgsz Falken är afflagdh och thetta effterschriffne är inlagt udi en bodh wed Nässet och therpå haffver warith” (meaning Viborgs Falken is retired and following things are stored in a small house at Björkenäs”). The inventory lists a number of sails which, according to Bjerre, indicate that Falken was rigged with three masts.

Finska Falken is reported to have remained visible above the water surface as late as the 1950s during low tides. The shape of the bow looks like a dragon, and the wreck was therefore locally called “the Viking ship”. Divers reported evidence of charring on the timbers, suggesting that the vessel had been affected by fire. Locals have probably collected timber from the wreck ever since it sank. Divers in the 1950s are reported to have salvaged timbers, cannonballs of various calibres, bricks from the ship’s galley, and a circular stone with a central hole, believed to have been an early grapnel anchor.

Divers in the 1950s measured the wreck of Finska Falken to 27.5m which corresponds closely with our own measurements of 27x5m. Bjerre also refers to a traditional rule of thumb whereby the keel length can be multiplied by 4/3 to estimate a vessel’s overall length. If this relationship is applicable in the present case, Finska Falken would have measured approximately 37 m overall.

The Search

Today the bays north of (Kläckebergaviken) and south of (Krafslösaviken) the headland Björkenäs are shallow with depths of no more than approximately 4 m. In addition to surveying the bays themselves, we also conducted a side-scan sonar survey of the approach to the former shipyard from seaward, as several shoals in this area could potentially have caused shipwrecks.

The survey was carried out using a hull mounted side-scan sonar from Lowrance (HDS9Pro + Active Imaging HD). Using a side-scan sonar requires very calm sea conditions to produce detailed images of the seabed.

In April 2026 the sea was calm, and we spent around half a day surveying the area for possible remains associated with the historic shipyard. All sonar targets were recorded using GPS.

The next challenge was to find suitable conditions for diving, requiring clear water, calm weather, and availability for both of us. These conditions coincided on 31 May 2026, when the dive investigation was carried out. We recognised that this was probably the last opportunity to conduct the survey before the seasonal growth of aquatic vegetation significantly reduced visibility and obscured archaeological features on the seabed. In this area, early spring generally provides the best diving conditions, before vegetation covers much of the seabed.

The bays are very shallow nowadays.

The overlaid symbols on the Google Maps image below indicate the features described in the following chapter.

Figure 5, search tracks, several hours of work. There are shallows to the East in the waterway into the shipyard. We hoped those shallows would have caused some unhappy sea captains as well but that gave no results.
Figure 5, search tracks, several hours of work. There are shallows to the East in the waterway into the shipyard. We hoped those shallows would have caused some unhappy sea captains as well but that gave no results.
Figure 6, best place for a shipyard based on today’s depths seem to be the SE tip of Björkenäs. The shallows we searched for at the entrance from the sea are marked with a red ring.
Figure 6, best place for a shipyard based on today’s depths seem to be the SE tip of Björkenäs. The shallows we searched for at the entrance from the sea are marked with a red ring.
Figure 7, the location of the interesting findings.
Figure 7, the location of the interesting findings.
Findings

We successfully located the two wrecks immediately north of Björkenäs. Finska Falken was clearly visible in the side-scan sonar data, whereas the smaller wreck lay in water too shallow to be detected effectively by the sonar and was instead located during the dive survey.

The two remaining wrecks marked in the northern part of Kläckebergaviken (Figure 2) were not located. As the water in this area is extremely shallow, they are likely to lie very close to the shoreline. Future investigations should therefore include shore-based diving to search for these wrecks.

Finska Falken was measured to 27x5m and rests in 1.5m deep water with the shallowest part, the bow, only 0.5m below the surface, figure 7. The frames are up to 25 cm wide and are closely spaced, particularly amidships, where they are almost touching. The keelson is approximately 40 cm wide and terminates abruptly 4–5 m short of the bow. Beyond this point, a slightly tapering structural member continues towards the bow. Ballast stones are also present within the hull.

The smaller wreck was measured to 15m long and had significantly lighter construction and the depth is even shallower than that of Finska Falken.

We found a pile of uniformly sized (30cm) ballast stones, figure 7. The bottom around is all flat and sandy so the pile really stuck out on the sonar, i.e. probably not natural. The pile is 17m long and shaped like a ship. In one place there is an old piece of timber, but it is unclear if it is connected to the pile or just has sunk there. No frames were observed protruding from the ballast, as is commonly the case at historic wreck sites. Either is it just a pile of ballast stones or the wreck is so old that no wood remains above the sea bottom. (Finska Falken sunk 1566 and the wood there is in good condition).

We located two mooring dolphins in the centre of the southern bay. (Krafslösaviken), figure 7. They both consisted of two 40cm diameter poles and where still standing upright from the seabed at 40 degrees angle some 35m apart. Their prominent relief above the seabed produced distinctive side-scan sonar returns.

Elefanten was also surveyed using side-scan sonar (Figure 11). As the wreck has already been well documented, it is not discussed further in this report.

In addition, three concrete-and-steel mooring blocks were identified closer to Björkenäs than the mooring dolphins. According to Robert Holm, sailing boats were moored in the bay until relatively recent times, indicating that these features are of modern origin and are not associated with the historic shipyard.

A number of isolated timbers were also detected at various locations but were not considered sufficiently significant to warrant further investigation by diving.

Figure 8, Finska Falken, the bow that today is only 0.5m below surface can be seen in the bottom left corner as a brighter echo. The large keelson is also clearly visible..
Figure 8, Finska Falken, the bow that today is only 0.5m below surface can be seen in the bottom left corner as a brighter echo. The large keelson is also clearly visible..
Figure 9, the ballast pile. No ribs were found but certainly an old piece of timber marked with a circle. The timber may not belong to the pile.
Figure 9, the ballast pile. No ribs were found but certainly an old piece of timber marked with a circle. The timber may not belong to the pile.
Figure 10, the two mooring dolphins that are some 35m apart. Both are made of 2 logs connected at the top and still standing at an angle up from the bottom.
Figure 10, the two mooring dolphins that are some 35m apart. Both are made of 2 logs connected at the top and still standing at an angle up from the bottom.
Figure 11, Elefanten.
Figure 11, Elefanten.
Summary of findings

1 Finska Falken, 27m long: N56 42.983, E16 22.072

2 Wreck 15m long: N56 42.964, E16 21.999

3 Pile of ballast stones 17m long: N56 42.766, E16 22.091

4 Two mooring dolphins 35m apart: N56 42.863, E16 22.360 &  N56 42.847, E16 22.374

5 Elefanten (already well known and investigated multiple times): N56 42.797, E16 22.777

Figure 12, the keelson abruptly ends 4-5 meters before the bow.
Figure 12, the keelson abruptly ends 4-5 meters before the bow.
Figure 13, the slightly pointed structure between where the keelson ends and the bow.
Figure 13, the slightly pointed structure between where the keelson ends and the bow.
Figure 14, the dragonhead like bow just below the surface.
Figure 14, the dragonhead like bow just below the surface.
Figure 15, the keelson and ribs.
Figure 15, the keelson and ribs.
Figure 16, carved out rectangle 80cm long and 5cm deep in the keelson and possibly the mast or a beam to hold up next deck to the right.
Figure 16, carved out rectangle 80cm long and 5cm deep in the keelson and possibly the mast or a beam to hold up next deck to the right.
Figure 17, outer hull planking (carvel) from top to bottom in the picture.
Figure 17, outer hull planking (carvel) from top to bottom in the picture.
Figure 18, ballast stones in the wreck.
Figure 18, ballast stones in the wreck.
Figure 19, the wreck is easily seen from above the surface.
Figure 19, the wreck is easily seen from above the surface.
Figure 20, Micko standing on the smaller 15m long wreck.
Figure 20, Micko standing on the smaller 15m long wreck.
Suggested future work

Professional marine archeologists should investigate findings 1-4 and possibly take dendrological samples and/or C14 samples.

Additional snorkelling and diving surveys along the shoreline are recommended to document further remains associated with the shipyard, as well as any wrecks that were not located during the present survey but are indicated on historical photographs and reported to have been visited by divers in the 1950s. Interviews with local residents may also provide valuable information regarding the location and history of submerged archaeological remains.

References

[1] Fornsök, gives information about the shipyard area on land

[2] 1956-11-24 there was an article in the local paper Barometern about Finska Falken by Stig Bjerre, city notary and sport diver

[3] Erik Enström wrote an article about Finska Falken in the journal Marinarkeologisk Tidsskrift 1987:4

[4] The journal Frimuraren 2016:1 tells a story about black oak from Finska Falken

[5]” The Mukran Wreck” by Maik-Jens Springmann in Nordic Underwater Archeology April 1999 also mentions Finska Falken as a possible wreck found outside Rügen in 1994 that was supposed to have sunk outside Warnemünde 1564-07-11

[6] Svenska Örlogsfartyg 1561-1570 mentions several ships by the name Finska Falken and possible confusions like Finska Falken, Viborgs Falken, Viborgs Pippingen, Buffeln and Marcolphus.

Authors, explorers and divers
Micko Björck.
Micko Björck.
Erik Håkansson
Erik Håkansson
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