The Baltic is one of the most polluted bodies of water in the world. A unique partnership removes oil from sunken wrecks in this northern sea.
The Baltic Sea contains so many shipwrecks that it has been called the world’s largest underwater museum. This pleasant description ignores the fact that some of the exhibits are ticking time bombs. Many of these wrecks went down loaded with fuel.
As the vessels erode over time, oil is released and becomes a major threat to the local environment.
There hasn’t been a great deal of research done on oil escaping from shipwrecks. Many vessels were known to have sunk, but their condition and precise locations on the sea floor were unknown, and the field work required a plenty of resources.
To find, categorise and clean these wrecks, the Finnish government, companies and private individuals have formed a partnership.
A shipwreck leaking oil is a headache anywhere, but it becomes a migraine in the Baltic. The coastlines are packed with islands and seaways that are narrow and shallow, which makes the clean-up a nightmare. For example, in 1984 a 200-tonne oil spill contaminated 2,000 square kilometres and 200 islands.
The slow exchange of water due to narrow seaways and the dense population in the area have contributed to making the Baltic one of the most polluted seas in the world. Heavy nutrient loads cause eutrophication while overfishing and invasive species
threaten the already fragile ecosystem. The last thing the Baltic Sea needs is old shipwrecks leaking heavy fuel oil.
“We have identified about 150 wrecks that we need to keep an eye on, and about 20 of them are considered critical,” says Jorma Rytkönen, Development Manager at the Finnish Environment Institute SYKE. “Many of these are war wrecks
in sensitive areas. A good example is the Soviet destroyer Gordyi.”
In 1941, Gordyi ran into a mine field and sank almost in the centre of the Gulf of Finland. For 70 years, she has been out of sight. Today there is a real threat that the old fuel oil in her bunkers will leak into the Baltic.
Fortunately, the volunteer divers of Badewanne are ready to help out. Badewanne is a non-profit diving team that has been documenting shipwrecks in the Gulf of Finland for more than two decades.
“Badewanne makes brilliant videos of these wrecks and have a deep knowledge of them,” Rytkönen continues. “We really need those skills to be able to safely and efficiently manage these leaking wrecks.”
“We dive with a purpose,” says volunteer diver and Badewanne member Sam Stäuber, Head of Directors and Production Specialists at YLE, Finnish National Television. “We know that resources are limited for authorities, so we are willing to help document these wrecks and participate in salvage operations.”
Surveying and visiting a wreck is valuable, but keeping a long-term watch on it is even better. The Wärtsilä Project Baseline team is working with Badewanne to survey wrecks for potential oil leakage and experimenting with the use of sensors to detect it.
All this work to find and document wrecks that are leaking oil is only the first step. When necessary, they must remove the oil from the wrecks. This was done with two ships in the summer of 2020: the Hanna-Marjut and the Fortuna.
On a windy October night in 1985 the 81.8-metre Hanna-Marjut was bringing a load of sugar beets from the Åland archipelago to mainland Finland. The cargo hatches were likely broken open in the rough seas and the hold quickly filled with water, causing the ship to sink.
Remarkably, history repeated itself soon after. In October 1987, Fortuna was shipping sugar beets from Åland to the mainland when she sank about 700 metres from the Hanna-Marjut.
Removing the fuel from these small coastal vessels was a priority since they were in a sensitive environmental area and they had a high probability of leaking fuel. Located at depth of 30-40 meters, the ships were at a reasonable depth for divers.
The team members scoured archives to determine the fuel tank arrangements on board as well as clues as to how much fuel they might have been carrying when they sank.
“We had some bad information about the Fortuna, so the help from Badewanne was critical to locate the tanks,” says Rytkönen.
SYKE’s research vessel Aranda surveyed the wrecks with side-scanning sonar and multi-beam echosounders, and the team put together detailed 3D images. Divers took samples of the sea floor and set up sensors while Badewanne divers took photos. Volunteer diver Mikko Gustafsson, Chief Project Engineer at Wärtsilä, helped remove “ghost nets” from the Fortuna. Ghost nets are commercial fishing nets that have been lost or left in the ocean by fishermen.
“There were nets across the cargo bay, so we cut them loose and removed them so no one would get entangled,” Gustafsson explains. “This was on the dive to scout the route to the oil tanks. When we came to the surface they immediately sat down and started planning the next dive and next step of the operation.”
The process to remove the oil from the wrecks was a significant job, involving the Finnish Environment Institute, Navy, Border Guard, Heritage Agency, Transport and Communications Agency, Ministry of the Environment, private corporations, the Badewanne diving team and individual volunteers. The goal was not just to remove the oil, but also to further develop cooperation between such a diverse group of public and private entities.
“We removed about seven-and-a-half tonnes of oil from the fuel tanks on each ship,” says Rytkönen. “We couldn’t get to the day tanks in the machine room because of debris, but we believe the amount of oil there is low.”
The operation was a major success. Oil was removed from the old wrecks, protecting the environment from the risk of a leak. Additionally, a diverse group of people and institutions learned to work more effectively together. They have even more ambitious plans for the future and want to include international partners.
Finnish authorities are eyeing two wrecks for 2021 expeditions. They hope to remove the oil from themselves in one wreck, but the other wreck is in much deeper water and will probably require international specialists who have experience in using remotely operated underwater vehicles.
In addition to recovering oil, the team is also planning on recovering two paravanes from World War II-era wrecks. These glider-like devices were towed underwater to cut cables anchoring mines. Each could contain about 9 kilos of mercury, which is especially hazardous to the environment.
“There are some wrecks closer to Russia that might give us an opportunity for trilateral cooperation,” says Rytkönen. “I would love to see Estonia, Russia and Finland working together on these.”
Wärtsilä encourages their employees to help environmental causes and also directly supports this work.
“It is extremely expensive to carry out these cleaning operations,” says volunteer diver Mauro Sacchi, Director, Business Development at Wärtsilä, and Badewanne member. “The maritime environment is critical for everyone, so it is good that ordinary people can participate with citizen science and corporations can contribute talent or money.”
“At heart we are divers,” says Gustafsson. “This work is important to us and benefits everyone. We do it because we are passionate about it and are willing to sacrifice time and money to help. Your wallet gets dry when you get wet!”
We do this for the love of diving,” says Stäuber. “We are very privileged to participate in these operations. Many of these divers do this as a profession, and we are just dedicated volunteers. We get to see diving done from a different perspective, and we admire how they work. It is awesome to see.