Getting up close to centuries-old shipwrecks in underwater museums

The casual diver might mistake a warship for a mat-washing platform, but the researcher can tell the story behind the lump of wood. The Porkkala peninsula is a treasure trove for marine archaeologists.

It is a beautiful summer’s day out at sea. Sunlight dances on the waves and there’s a gentle breeze blowing. But that tells nothing about the diving conditions. It is dark and cold below the surface and the currents are strong.

We are on the Porkkala peninsula, looking towards the island of Träskö. Ten metres below us lies the ‘Cannonside Wreck’. The members of the Finnish Maritime Archaeological Society are planning to take a sample for dating the wreck.

They will be testing a new type of drill, which is less damaging to the wreck than earlier methods.

Nobody knows the story of the Cannonside Wreck. It is thought to have been a warship from the 18th century, but there is no record of where it came from or where it was going.

“A dating sample is the first step. Then we can begin to piece together the history of the wreck,” says Kristin Ilves, associate professor of marine archaeology.

The work requires patience: safety always trumps speed, and the work can be held back by strong winds and currents. Ilves, who began her archaeology career on land, says it took a while to get used to how much more time everything takes underwater.

“At sea, a large chunk of your time is taken up just hanging around. Even well-laid plans can fall through, as there’s always something unexpected,” she says and opens her laptop in the cabin.

This rings true for today’s expedition as well.

The treasure trove of Porkkala

The Porkkalanniemi peninsula has always been a busy junction for maritime trade. Over the centuries, dozens of ships have been shipwrecked in its waters.

Nowadays, the area is a treasure trove for diving enthusiasts and researchers. The recently-established Porkkala Wreck Park has four sites marked with signs and mooring buoys. The aim is to gradually bring more of these attractions to the park.

Finland’s regional waters offer marine archaeologists a wealth of research material as there are plenty of wrecks in good condition in this part of the Baltic Sea. This is because the shipworm, that has already spread to the southern part of the Baltic Sea and would destroy these wrecks, does not thrive in cooler, low-salinity waters. On the other hand, it is unclear what future effects global warming might have.

Getting wet

The Porkkala Wreck Park is a good example of citizen science: amateurs are an indispensable source of help for the researchers. The amateur divers let the researchers use their ships and equipment whilst also providing the human resources. Without them, the marine archaeologists would struggle to gather as much material. Their shared passion drives both amateurs and researchers.

“For me, the most important thing is knowing that there are people out there who are truly interested in what I do,” says Ilves.

Professor Ilves believes that when archaeologists share their work with the public, and not just their colleagues, it increases appreciation of the cultural heritage and more generally an interest in history. 

In the wrong spot

It is not exactly smooth sailing on today’s diving excursion. The first ones to dive are Topi Sellman and Vesa McDermott, two members of the Finnish Maritime Archaeological Society.

They are underwater for quite some time but come back empty-handed. They could not locate the shipwreck.

“This is quite typical. Even though you know the wreck is there, you just can’t find it because of the poor visibility,” says Eero Saarinen, a biology student and society member.

The wrecks’ coordinates are known, but few would have the equipment to detect them beneath the surface. The wrecks are sought with the help of a compass, except now it turns out that the mooring buoy marking the wreck has shifted. The men are looking in the wrong spot.

Murphy on board

Eero Saarinen is one of the youngest members of the Society. Ever since childhood he went hunting for underwater treasures with his father and later rekindled his enthusiasm for shipwrecks. Saarinen thinks exploring wrecks suits biologists as well: “A shipwreck is a reef – even in Finland. There’s a lot of life there; fish and mussels, for example.”

Saarinen is beginning his MSc studies in microbiology this autumn. He thinks microbes in shipwrecks could present an interesting object of study in the future.

Saarinen, and Markku Luoto, president of the Maritime Archaeological Society, are the next ones to try their luck. This time they find the wreck, and are able to attach a pneumatic drill, with the intention of drilling a sample out of a support beam. The 12-millimetre-wide bore sample of oak will show tree growth rings.

For a moment, everything is running smoothly, until the air hose comes off the drill and resurfaces. As do Luoto and Saarinen.

Luoto vents his frustration: “Looks like we’ve got Murphy on board.”

Ship or jetty?

Luoto works in IT and has marine archaeology as a hobby. In the 1990s, he studied computer science while taking maritime history as a secondary subject, leaving him with a lifelong interest in the field. Luoto’s sons also dive.

According to Luoto, researchers have a lot to offer recreational divers, many of whom have marvelled at the wrecks and wish to make sense of them.

“An inexperienced diver might mistake a warship for a sunken jetty,” explains Luoto, “while a marine archaeologist can tell the story of that piece of wood.”

Divers are motivated by a wish to be of help in the scientific research through their excursions.

Safety first

There are marked wreck parks in a variety of locations. Of upmost importance is the safety of the divers. In a properly managed wreck park, there are sites for beginners and expert divers alike.

The Baltic Sea’s first wreck park off the Helsinki coast, and featuring the wreck of the Kronprins Gustaf Adolf, was opened in 2000.

“When my sons began to dive, we went to the Gustaf Adolf wreck park. It was an amazing experience. And then we came to think, why not create more wreck parks,” says Luoto.

The Porkkala project began in 2018. Each wreck was flagged with buoys and signs, with the goal of marking out a couple of new wrecks in the area each year. The Finnish Cultural Foundation has granted 35,000 euros for the dating of the wrecks.

“Divers appreciate the wrecks more when they are being looked after. The minute something is declared a museum, the souvenir hunting ends.” Luoto describes the approach: “In placing the buoys for mooring, they are not attached directly to the wrecks, as in the past that has torn them to pieces.”

 

Drilling economically

The researchers take dendrochronological samples from the wrecks for dating purposes. The samples’ annual growth rings are then compared to chronological records to find out when the tree grew, making it possible to determine the age of the wreck. Until now, the samples have been extracted using a saw, which has proved difficult underwater: you cannot use your own body as a counterweight. The Finnish Maritime Archaeological Society has developed new tools for sampling. Using an auger to bore out a sample makes it easier for the researchers and causes less damage.  

“The Porkkala Wreck Park is a museum. To ensure a great visitor experience, less intrusive sampling methods are needed,” Luoto says. The development of the tools has been a long process. The drill used last year worked but proved too slow to use, since the aim is to get a sample within half an hour.

Luoto has tried using ratchet tie-down straps and a clamp. Friction caused by the drilling boiled the sawdust into cellulose, which clogged up the drill. A vertical drill was needed. The researchers bought the smallest available and the divers adapted it to take samples underwater.

Duct tape to the rescue

Last week the latest version of the drill was trialled at the Suomenlinna sea fortress. All went well, but today things are different. Sellman and McDermott return to the drilling, but the drill gets stuck again. The hose of the low-pressure compressor melts and sets off the fire alarm. Luoto fixes the hose with duct tape, cable ties and a glove.

“You wouldn’t believe how important duct tape and cable ties are in marine archaeology, not to mention the occasional glove,” Luoto laughs.

The currents carry away the lift bag with the tools and the ROV camera used in underwater filming. Saarinen swims after them.

Sellman and McDermott are starting to run out of air, so they return to the boat to catch their breath. Luoto ends up diving to detach the drill on his own. Now the sample is finally on the surface – but it is stuck inside the drill.

“We’re going to need a hydraulic press to get this out,” Luoto says.

The drill itself worked well, and the core sample is the longest they have been able to obtain so far. The problems they had will serve as a useful lesson for next time, and the drill refinements are part of an ongoing process.

“If this was just a walk in the park, it would be boring, I reckon,” says Eero Saarinen.

It is about us

Is marine archaeology all about the diving? Not at all: beneath the surface lie social structures. Among other things, marine archaeology studies the relationship of humans to water: the sea, the lakes, and the rivers.

Due to post-glacial rebound, the objects of research are often to be found on dry land, like the Viking-Age harbours and landing sites that Ilves studied for her PhD. The field is seen in terms of underwater adventures, but the marine archaeologist knows that to be only part of the picture. Ilves is currently studying the identity of the late Iron Age people who dwelt in the archipelago.

The wrecks offer a material source of information about the history of humankind, raising many questions: where did the innovations come from? Where exactly were the timber and nails sourced? What goods were being transported - where were they from and where were they going? And what do the ships’ quarters reveal about the society and its structure? How were goods taxed, or were they smuggled?

”In the end it’s not about the ships, it’s about us,” says Ilves.

The article has been published in Finnish in the 6/2020 issue of the Yliopisto magazine. It was translated by the following English philology undergraduates: Veera Haimakka, Jaana Helminen, Katja Kiipula, Vilma Kurikka Juuso Lehtinen, Alice Lindström, Sini Pesonen, Polina Polotaeva, Essi Savijoki, Janita Thusberg, Ossi Turpeinen, Iina Vertio and Veera Vikstedt. It was post-edited by John Calton, lecturer in English at the Department of Languages.

Can you go near the wreck?

A group of three marine archaeologists from the Finnish Heritage Agency carry out inspection dives, in other words go to checking out sites that divers, fishermen and cartographers have informed them about.

Minna Koivikko defended her PhD in marine archaeology at the University of Helsinki in 2017, the first to do so in the whole country. She investigated the old vessels around the Suomenlinna sea fortress, and how they might be exploited for recreational use.

You are allowed to dive to inspect the wrecks but you cannot disturb them. Koivikko reckons that in general Finnish divers honour this principle.

“The wrecks are underwater museums which you can drop in on any time,” Koivikko points out.

A protected zone has been established for some of the wrecks and a research permit is needed for access. These zones are being preserved for future researchers.

Arkeologi Minna Koivikko sukeltaa Suomenlinnassa inventoimassa kulttuurimaisemaa.

Photo: Petri Puromies

3D wrecks

Shipwrecks used to be documented with photographs, sketches and measuring. Now 3D modelling has replaced those methods.

 “Diving enthusiasts started doing the 3D modelling and we got all excited about it. We asked them to teach us how to do it. Since then I have been on some courses abroad and we have also organised training on the subject that is open to amateur divers, too,” says Minna Koivikko, an archaeologist working with the Finnish Heritage Agency.

Without the modelling technique, it is difficult to make sense of the broken and mud-covered wrecks on the sea bottom. It is important to see the whole picture, so the modelling helps, even if it is a little blurry. All it takes is an action-camera to film the subject from various angles beneath the surface, a process that takes about an hour. Afterwards a computer-generated three-dimensional model is compiled from the material.

Koivikko is happy with the arrangement: “Information flows both ways between scientists and enthusiasts. There is no segregation here, we all share the same interest.” 

The 3D models of the wrecks in Porkkala Wreck Park can be admired at wreckpark.eu.

 

 

Kaistale Tykkikylki-aluksen 3d-mallinnusta.

photo: Topi Sellman