Shipwrecks off coast of Helsinki contain oil, mercury and explosives
Swedish reefer vessel Coolaroo broke up and sank with full tanks of fuel
At least 30 shipwrecks have been located lying on the seabed off the coast of Helsinki, and more sunken vessels are found all the time.
Special researcher Juha Flinkman from the Finnish Institute of Marine Research (FIMR) believes, however, that most of the wrecks off the coast of Helsinki have already been discovered.
On the other hand, Flinkman also acknowledges that more unknown sunken ships may still be discovered in the near future. Thanks to the drop in price of so-called side scan sonar equipment, which enables a more precise mapping of the seabed, even private groups - hunting for shipwrecks as a hobby - can now afford one.
Previously, the military has been more or less the sole user of the devices.
Most of the wrecks outside of Helsinki are old, badly decomposed wooden vessels that fail to offer much excitement for recreational divers.
"This is largely thanks to the effect of ice, which can tear through the seabed and shatter shipwrecks up to a depth of 30 metres", Flinkman explains.
In Flinkman's opinion, if unknown wrecks are still to be found in the Helsinki waters, they lie in depths of several dozens of metres.
The brackish Baltic Sea water, however, tends to preserve wrecks. It is cold and low in salt, and therefore protects the wrecks from being eaten away by their worst enemy, the shipworm mollusc, which does not thrive in this environment.
The best-preserved wreck outside of Helsinki is the Swedish warship Kronprins Gustav Adolf, around which the Maritime Museum of Finland has constructed an underwater park with signs and visitors' books.
Not all the wrecks are open for recreational diving purposes, however. Particularly dangerous are warships and vessels containing oil. Finland's Environmental Administration has estimated that there are around 40 wrecks in Finland's territorial waters presenting a threat of an oil spill.
All of them are estimated to contain over one hundred tons of oil, thus presenting a considerable environmental threat to the Baltic Sea.
Only one of these wrecks, the Swedish refrigerated cargo vessel Coolaroo, lies on the seabed off the coast of Helsinki, where it sank after running aground and breaking up in 1961.
Since 2001, Finland's Environmental Administration has tried to ascertain if the vessel contains oil, and if so, how much. So far, the drilling exercises have proved impossible because of the sand and debris covering the vessel.
Old warships provide an altogether different risk.
"Most of them sank in full combat readiness. During World War II, there were more sea mines in the Gulf of Finland outside Helsinki than anywhere else in the world. Such was the German desire to keep the Russian fleet tied up in harbour", explains Flinkman, who has dived to many of the wartime wrecks.
The minelayer Königin Luise is presumably the most unpredictable wreck off the coast of Helsinki, and diving to the vessel is forbidden. "It contains depth charges, among other things. There is debris spread over a large area around the ship", Flinkman recalls. The vessel struck a Russian mine and went down in 1941 with the loss of 40 of its crew.
The mine clearance equipment may also contain mercury.
Many of the warship wreck locations have not been revealed to the general public. Most of them belong to the Defence Forces, until one hundred years have passed from the sinking. After that they become the property of the Maritime Museum.
Links:
The Maritime Museum of Finland
Helsingin Sanomat
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| 5.9.2006 - TODAY |
Shipwrecks off coast of Helsinki contain oil, mercury and explosives
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