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The Devil In Your Dive: My 70-km Traverse of the St. Lawrence River

Award-winning filmmaker, explorer and tech instructor Nathalie Lasselin spent 30 hours underwater braving a 70-kilometer stretch of the St Lawrence River surrounding Montreal, in the interest of water conservation—the river supplies 80% of Montreal’s drinking water and 50% of Quebec’s. How do you prepare for a scooter dive that includes drinking, eating, and sleeping underwater, while avoiding becoming Seadoo fodder? Nath tells all.



by Nathalie Lasselin
Images courtesy of N. Lasselin

You must have heard that idiom: “The devil is in the details.”  
If there is a god for the divers, trust me there is a devil as well.
Let me tell you how I met him.

Everything started years ago, when I began to ask myself  a recurrent question. I live in Montreal, and each time I come back home by plane, we fly over the St Lawrence river, and I couldn’t stop asking myself: What would it be like to traverse the entire island of Montreal in that river? If you take a closer look at the St Lawrence from up there, you will see a dark, greenish-brownish body of water flowing with rapids in different sections, being spanned by seven bridges, and containing lots of heavy ship traffic going to the great lakes.

But still, I had to see it with my own eyes, to feel it with my own body!  A dive so different from all my past experiences, having dived deeper than 110 meters in caves, in strong currents, in nearly no visibility, filming wrecks, and in the freezing water of the Canadian Arctic. I’d had years of training, teaching, exploring, and had always questioned the best way to do things (meaning the most suitable way to achieve my goals) And now I wanted to check it out, I had to try it. I had to do a lengthy, 70-kilometer/44-mile traverse in an impetuous river. I couldn’t stop thinking about it. It looked insane and not sexy at all for a dive plan, but my options were to attempt it,  or to one day become an old woman and regret that I hadn’t at least tried. Regret seemed worse.  

I started the preparation for my Urban Water Odyssey: The 70-km scuba diving traverse of the Saint Lawrence River from one end of the island of Montreal to the other, knowing I had to be obsessively meticulous about all the little details in the preparation for the dive on many different levels. There would be equipment, logistics, team, training, environment, a dive plan, mindset, as well as mental, physical, and psychological preparation. I was headed for a different kind of dive, one that would involve more than 30 hours of immersion in the water. 

So where to start? There was no guidebook, no written instructions for a dive like that. The challenge: A 70-kilometer obstacle course with a total time of more or less 30 hours in water, in rapids, strong currents, in low visibility, with structures—including ships and other hurdles such as  big rocks—to avoid.   

People didn’t understand why this project was so important to me. I  explained that one of the most important reasons for my passionate curiosity about this magnificent river had to do with the fact that the St Lawrence river is the source of drinking water for 80% of Montreal and 50% for the population of Quebec. We humans cannot live without water for more than three to five days, and we tend to take it for granted that clean water will flow when we simply turn on our taps. This alone was enough motivation for me to pursue my ambitious plan. 

In addition to the dive, I also wanted to collect water samples from the river, and planned to do so every 15 km/9.3 mi in the countryside and every 4 km/2.5mi in the city over a 350 km/217.5mi distance. My hopes for these samples was to determine how many and what kind of contaminants were present. The analysis would be handled by the chemistry department at the University of Montreal. As an underwater explorer, I felt privileged to be able to witness this environment first hand, and felt the need to do whatever I could to protect this most critical source for all life and make the public aware of the situation.

Preparing To Make The Dive

Going back to the basics, physically I needed to be on the top of my game and be fit for the dive, and I had to train differently to have a perfect core.  In order to do the dive safely, I would be towed by a DPV in one direction with a surface marker buoy attached to me that was going to pull me in the opposite  direction. My team had to know at all times where I was in order to give me an azimuth to follow so I would stay on my path. Anyone who had ever done a couple of hours of DPV with a CCR, bailouts, and some extra equipment, would understand easily how the pain slowly makes its home in your body. 

Of course, even if the water was around 20ºC/68ºF, after hours of immersion, cold could be an extra challenge, and I would have to eat and drink underwater to keep my energy. I trained to use a Kirby Morgan M-48 MOD-1 full face mask. My only option to go from OC to CCR, in order to have communication, would be to remove the mouthpiece part to eat and drink at the same time, as my safety diver would be keeping an eye on me. So I trained myself to be able to eat, drink and even sleep underwater using auto-hypnosis. 

More on Nath’s training: Drink, Eat, Sleep Underwater

Mentally, I had to be prepared to face doubt, adversity, fatigue, and pain. I had to  trust in the dive plan and my safety team. My motto, once I was in the water, would be that I had one job to do: go from A to B. The rest would not be in my hands anymore. 

To complete the picture, the logistics was undoubtedly the most time- consuming and delicate task when faced with the unknown. With a constrained budget, I had to figure out so many aspects to follow: the divers had to be trained to help me replace equipment underwater, to take samples for the scientific aspect of the mission, to obtain all the required pieces of equipment for the dive itself, and finally to put together three independent surface teams to relay with each other at specific points with five different boats. No one boat could follow the entire dive because of the nature of the river.

Over the months of planning, I gathered tons of equipment with the help of partners, manufacturers, and individuals in order to have the famous redundancy for every single item, from different pairs of fins in case it hurt too much on the arch of my feet, to back up CCR, and DPV. I decided to do the entire dive with my AP Diving Evolution CCR except for the 5 km of rapids that I would do on open circuit. 

Nearly one-third  of the dive is in non-navigable waters. The marine map is just white, no data, which means shallows, insane current, and numerous hazards. In that portion, I would face currents from every direction and intensity, as well as currents that were too strong to fight. Basically the river would beat me up and make me do loops and turn 360 in every direction. So for the rapids, being light on OC seemed to be my best option, which went nearly perfectly. 

Asking the Right Questions

Here some tips about how to ask the right questions. When preparing a dive—an expedition—we are not just divers anymore. At the end of the day, diving may be the easiest part, since we have the training, the skills, the equipment, the redundancy, and our regular dive buddy. But before, after, and during the dive, we are a traveler, a potential first emergency responder, a cook, a boat captain or passenger, and a guide. And, we might face adversity we had never encountered before with people in our group that we never worked with during a high stress situation. What we can do to make sure:

  • We agree on our what-if solutions
  • We know and are ready for our dive plan
  • We prepared our dive trip to perfection  
  • We have a harmonious, collaborative, and fun group of people who all agree on their roles and positions, on their strengths and weaknesses, without judgment.

With all these components, what is funny is that to a certain extent we do have control over them, and that may be why it is easier to list them, plan them and think about them. So if we do your job, a decent one at least, we should be all good to go for our next challenging or adventurous dive.

We took some time with the teams to train the divers and I told each of them, don’t trust yourself, don’t trust me, I may make mistakes. So everything should be double-checked and logged in the “Project Bible’’. As it got closer to D-Day, I asked myself what it was that I hadn’t thought of. I wondered what it was that would be obvious afterwards.

D-Day At Last

My dive started Friday September 14, early in the morning. At that time of the year in Montreal, mornings were usually filled with fresh humidity, and temperatures didn’t rise much. Except that day! 

One could think, “Well that was good news for the team on the safety boats. They would just drink less coffee or hot chocolate to keep them warm.” Nobody could be against a warm, sunny day on the river, right?  Nobody except me.  Because of that amazing, warm temperature, every single person who could take a day off from the office and who had a boat was on the river. Even if the river is pretty wide in Montreal, there is not a lot of water. The deepest part is in the seaway channels that need to be dredged. 

Sharing the rivers between marine traffic, pleasure boating, seadoo, kayakers, and stand-up paddle boards was not a good mix. Adding a diver into the equation, knowing that most of the people did not understand what a dive flag was, did not bode well for my project.

So guess what my beautiful path on paper and waypoints on the GPS became in a couple of hours? Nearly useless. Sharing the rivers between marine traffic, pleasure boating, seadoo, kayakers, and stand up paddle boards was not a good mix. Adding a diver into the equation, knowing that most of the people did not understand what a dive flag was, did not bode well for my project.

Finally I ended scootering with the shallows. In the St Lawrence river, like in many other bodies of water nowadays, invasive plants are taking all the sun and warmth of the water to grow up to the surface. In a matter of hours, I had transformed myself into an underwater lawn mower, overusing the batteries of the scooters and having to clean the props way too often.  

Nath’s harrowing incident: Close Calls: Nathalie Lasselin

That little warmer weather detail had a huge impact on the entire project.  What was supposed to take me an hour, based on all the proof of concept dives, took me twice, triple the time. I did all I could do not to stop, to go in the straightest line possible with my divers giving me a fresh DPV, a syringe of avocado or some high protein soup in a soft bottle. 

We worked all together with the first team that was supposed to be out of duty around 1 PM. Instead, by 10 PM, my dive supervisor said, “Either we pull the plug and you try it another time next year, or you agree to get out of the water and wait until sunrise to keep going.” It was true that I couldn’t cross the rapids in the dark. It was too dangerous and the supervisors knew they couldn’t guarantee the safety of not only me, but the entire support team, so they called the dive for that day. 

Braving The Rapids was No easy feat!

It was my own dear project. A project that couldn’t be completed without a support team, and in circumstances so much more different than any other dive.  The entire team of 25 persons involved agreed to stay with me no matter how long it took. 

The next morning at sunrise, I dove back in the river for another 15 hours.  The challenge was not easier on this day because marine traffic was even more intense than the first day.  Being in low visibility, low contrast, for a very long period of time, with fatigue, I started to experience the Charles Bonnet syndrome. Basically I saw things—colors, shapes that did not exist. At first I was surprised and then amused by what I saw as free entertainment to help me complete what was a monotonous scooter dive with not even five feet of visibility. My body was exhausted, my vision was impaired, but my mind was all there, so happy to imagine the point B.

At the finish line at last.

By Saturday at 10 PM, 12 hours after the planned ETA, I finally arrived at the finish line with the support of all my team. After the dive, it took me a couple of days to get back to a normal level of energy without any injury. The dive gave me the media visibility to talk about the adventure, to describe the team work, and to explain about the importance of the river as the source of our drinking water. 

My second piece of advice: No matter if it is a small dive or a big adventure, prepare for it the best way you can, with reminders and lists. Practice your skills with well-maintained equipment. By keeping an open mind, a close team working toward the same goal, with the humility and the flexibility to switch to the safest back-up plan, your adventure might be a different one, but still will be the most rewarding one, and the dream of one individual may become larger than themselves, “plus grand que la nature.” 

Additional Resources

Nathalie Lasselin’s Urban Water Odyssey Facebook Page

Discovery Channel: Nathalie Lasselin prepares for her traverse through the St. Lawrence River. 

Nathalie Lasselin is an award-winning filmmaker and producer. She trained at the National Film Board of Canada and is an arctic dive expedition leader, CCR, cave and wreck explorer and instructor. As an international speaker, a writer, and on-camera talent/technical dive specialist for TV shows, she shares her passion for discovery in a challenging environment. For the past years with her project, Urban Water Odyssey, diving the 70 km/44 mile long shore of Montréal, she brings people together to raise awareness and better action towards the preservation of fresh water. She is also a Women Divers Hall of Fame (WDHOF) inductee, Royal Canadian Geographic Society (RCGS) member, and a member of The Explorer’s Club.


A Conservator’s Reflections on the Andrea Doria

This month marks the 65th anniversary of the sinking of the SS Andrea Doria, once described as the “Mt. Everest of wreck diving.” Here veteran wreck diver/collector John Moyer, who was granted an “Admiralty Arrest” over the Doria in 1993, in order to recover its famed Guido Gambone ceramic art panels, recounts the key milestones of the deteriorating wreck, and his efforts to display her historical artifacts.




By John Moyer
Header image of the sinking of the Andrea Doria July 27, 1956
, and other photographs courtesy of John Moyer unless noted.

This year marks the 65th anniversary of the sinking of the Italian liner SS Andrea Doria. During the four years the ship sailed between Italy and New York, she was known as a “Floating Art Gallery.” The aftermath of the collision with the Swedish vessel, Stockholm, 80 km/50 miles south of Nantucket Island off the coast of Massachusetts, was described as the greatest sea rescue in history.

The statue of Genoese Admiral Andrea Doria.

Peter Gimbel was the first diver on the wreck on July 27, 1956—the day after it sank—and he returned the following year to photograph it again for Life Magazine. Capt. Dan Turner took a team of divers to the wreck aboard his ship the Top Cat in 1964. Turner blew a hole in the Promenade Deck and recovered the life-sized bronze statue of Admiral Andrea Doria from the First Class Lounge. Unable to free the statue’s base from the deck, they cut it off at the ankles with hacksaws. Four years later, Italian film producer Bruno Vailati led an expedition to survey the wreck and determine if it could be refloated. The Fate of the Andrea Doria(English title) was comprised of footage taken throughout the expedition team’s 21 dives, and the journey inspired Stefano Carletti’s classic book, Andrea Doria-74. 

Gimbel returned to the Doria in 1975 to test his theories on exactly what caused the ship to sink; this research inspired his film, The Mystery of the Andrea Doria. He discovered that the Doria had sustained massive damage to it’s hull when the Stockholm hit. During his next expedition in 1981, Gimbel and his team salvaged the ship’s safe, which he opened later that year on live TV. Various other teams also investigated (or attempted to investigate) the wreck during this time period. Some just explored the sunken vessel, some returned home empty-handed, and some didn’t even make it to the wreck site.

I remember hearing about the Andrea Doria for the first time in 1975 at a shipwreck artifact show in Brielle, New Jersey; the Eastern Divers Association orchestrated the event. I met some divers there who told me about a wreck they described as the “Mt. Everest of Diving.” She was a massive 213 m/699 ft-long passenger liner lying on her starboard side, 74 m/241 ft in the cold, dark North Atlantic. That area of the ocean is known for frequent storms, rough seas, and strong currents. The divers said they often had to pull themselves hand-over-hand down the anchor line, fighting to reach the bottom. Visibility averages about 8 m/26 ft, so they had to be careful not to get hung up in the commercial fishing nets that had snagged the exterior of the wreck. Because she is on her side, it’s easy to become disoriented when penetrating the wreck. The interior is a confusing maze of ceilings that are now walls, walls that are now floors, and stairwells that run sideways. It is filled with silt; the water may be clear when you swim in, but picking up an artifact decimates the visibility, so divers often have to feel their way out. Steel cables and wires hang down, and divers can easily become entangled. When I left that show, I knew I wanted to see the Andrea Doria for myself.

My First Doria Dives 

Moyer’s first dive on the Doria in 1982. Photo by Chuck Zimmaro

In 1982, I dived the wreck for the first time with a small group of divers on a chartered boat. We anchored at the forward end of the Promenade Deck, and I made three dives exploring the area. My first finds were two silver jewelry boxes and a brass-framed window. The next year, we began diving into the ship’s first class dining room where we found piles of china dishes and glassware. In 1985, a dive team and I spent a week on the wreck and recovered the 68 kg/150 lb brass bell from the ship’s aft steering station.

After that 1985 trip, I began my serious research into the ship and collected everything I could find related to the Andrea Doria. I traveled to Italy to meet with the engineers at Ansaldo Shipyard—who had designed the ship—and the Italia Line officers who were onboard the night of the collision. I also corresponded with Bruno Vailati to get his insight into diving on the wreck. Between 1985 and 1991, we made many trips out to the site, exploring new areas of the wreck and recovering any artifacts we found.

In 1992, based on information I had received from Italy, Billy Deans and I began searching the bow of the wreck for the ship’s main bell. We entered through a hatch, swam along a corridor, then up a hallway to the room where I was told it was stored. When I pried opened the door, I found the room was filled with about 1 m/3 ft of silt and debris. Later that year, I took a team of 15 divers and crew aboard the R/V Wahoo and spent a week cleaning out the room with an airlift. Unfortunately, we did not find the bell.           

John Moyer and Capt. Billy Deans preparing to dive the Doria

During the winter of 1992-1993, Rinaldo Negri, who had helped design the Andrea Doria, sent me a book with a photo of the ship’s Wintergarden Lounge; the photo captured the lounge’s large wall panels inlaid with ceramic sculptures created by Italian artist Guido Gambone. I was able to match that photo with the ship’s plans and determine exactly where the works of art were on the ship. Billy Deans and I dove into the Wintergarden and found that two panels had fallen from their mountings and were lying deep inside the wreck. Later that summer, I returned on the R/V Wahoo, this time with a team of 20 divers and crew, to recover the panels. Over a period of four days, working in near zero visibility at a depth of 61 m/199 ft, the team rigged each 454 kg/1,000 lb panel  with inflatable lift bags and floated them to the surface.  

Recovering the Gambone ceramic panels. Photo by Bill Campbell
Moyer with the restored Gambone panels . Photo by Steve Gatto.

Prior to the expedition, my attorney filed legal papers in the US District Court in Camden, New Jersey. Judge Joseph Rodriquez granted an Admiralty Arrest, asserting the court’s jurisdiction over the Doria, and appointed me custodian of the wreck. I was required to attach the signed arrest papers (inside a sealed container) to the wreck. Later that year, we again appeared before Judge Rodriquez. We argued that, although insured by an Italian consortium, the underwriters had made no attempt at salvage in nearly 40 years; therefore, they had abandoned the wreck. The court agreed and named me Salvor-in-Possession. This gave me exclusive salvage rights, clear title, and ownership of anything we recovered. I did not want to shut the wreck down from recreational divers and have allowed them to continue to dive it, to photograph, and to recover small artifacts. In his ruling, the Judge stated: “Moyer’s independent research and archeological documentation of salvage efforts indicate a respect for the Andrea Doria as something more than just a commercial salvage project.”  

Warrant of Arrest for the Doria.

Displaying The Doria

From the very beginning, my intention was to collect certain artifacts from the wreck and as many items related to the ship that I could find. I wanted to create an Andrea Doria exhibit to tell the story of what some call the most beautiful ship to ever sail. I have put on dozens of temporary exhibits and displays over the years and hope someday to have a large permanent exhibit. The general public has always been very interested and pleased to see what we have recovered. I am also working closely with Andrea Doria survivor Pierette Simpson. She is the author of Alive On The Andrea Doria and produced the award winning film Andrea Doria: Are the Passengers Saved?

We have held many events, participated in film screenings together, and have ridden in the New York City Columbus Day Parade (along with other survivors and Ted Hess, lead diver of Gimbel’s 1981 expedition). At the end of the parade, there was a ceremony where Pierette rang the Andrea Doria bell in memory of the souls who lost their lives in the sinking. We are currently working with The Noble Maritime Collection in Staten Island, New York on an exhibition which will open late spring 2022.

The inevitable decay of sunken ships is slow and most often unobserved.  The sinking of the Andrea Doria produced a wreck of very unusual characteristics. Due to newsreel camera planes circling overhead, it became world famous, and its final resting place is accessible to divers. When Peter Gimbel first visited the wreck in 1956, he saw no obvious damage to the ship. Since then, divers have been reporting major decay events on the wreck. The wheelhouse was still intact when the Italian dive team filmed it in 1968, but it was gone by 1973. The funnel, mast, and top three decks of the superstructure had fallen off by the time I first dove it in 1982. We used the port side bridge wing as a landmark until it fell off sometime in the early 1990s. The Wintergarden was completely intact when we recovered the Gambone sculptures in 1993, but it totally collapsed only two years later.

John Moyer and Gary Gentile recovered the statue base in 1996

Later in the 1990s, we noted cracks in the hull and the Boat Deck, Upper Deck, and Foyer Deck had started to slide downward to the sea floor. A recent multibeam sonar scan by the University of New Hampshire showed that the cracks have expanded and that the hull has entered its final stage of the flattening process.   

Someday the Andrea Doria will be an unrecognizable pile of debris on the bottom of the sea. Fortunately, we have been able to rescue many historically important artifacts and unique works of art before they were lost forever.

Additional resources

InDepth: Stefano Carletti: The Man Who Immortalized The Wreck of the Andrea Doria By Andrea Murdock Alpini

Alert Diver: Remembering the Andrea Doria by Michael menduno

Diver: Doria Tipped The Scales by Michael Menduno

John Moyer’s first dives were in 1970, and he began diving on shipwrecks in 1975.  He has made thousands of dives on wrecks in the US, Canada, Great Britain, Mexico, and the Caribbean. He has dived on the liner RMS Empress Of Ireland, Ironclad Monitor, Light Cruiser USS Wilkes-Barre, and was one of the first Americans to dive on the WW1 German fleet in Scapa Flow, Scotland.  

He has a degree in Biology from Stockton University, a USCG 100 Ton Master License, and worked as an Instructor at the Dive Shop of New Jersey and Key West Divers.  Moyer is a member of the Atlantic Wreck Divers Dive Club and is the recipient of the prestigious Pioneer of Northeast Diving Award. He has appeared on the History Channel, A&E Network, and Dateline NBC. He is co-author of “The Decay of the Andrea Doria,” published by the Society of Naval Architects and Marine Engineers, and he appears in the docufilm Andrea Doria: Are the Passengers Saved?

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I trained with self hypnosis prior to the dives in order to help me to be more at ease with pain resulting from the long hours being towed by the DPV and pulled by my buoy and the weight of a full face mask and helmet. It also helped me to fall asleep underwater.

The technique initially uses mental concentration on a visual focus point (in my case it was my thumb) as well as introducing a well-rehearsed mental suggestion to induce a specific state.  After some minutes, your head becomes so heavy that you just fall into a state of sleep. It is not real sleep that occurs when you are asleep in your bed. It is more like a trance state in which you can be aware of your surroundings—in my case, I was aware that my safety diver was holding my hand and observing my breathing—but you simply can't move. You don't want to anyway, because you are so peaceful and relaxed; 20 minutes in deep hypnosis can feel like four to five hours of sound sleep. 

I trained for several months nearly every day in order that my brain and body would know exactly what to do without my direction, without the guidance of my audio commands. With training, it became like a muscle memory in a sense. Practicing auto hypnosis underwater is very different than doing so on your couch at home. I thought It would be hard to breathe, but it worked very well.









On Saturday, I kept on going, diving the rapids and the bridges. I didn’t reach the end before night. With heavy boat traffic and other challenges, everything took more time. We changed gear again for night set-up, but we were getting close to the end, finally.


We were just 3-4 km/1.8-2.4 m from the end. In the pitch-black night of Montréal, in the pitch-black waters of the river, I was scootering my way, looking at my compass when I heard Anne Marie screaming: “Nath, come up, come up now!”


Her tone of the voice did not leave room for question. I tried not to come up too fast, and when I reached the surface, something hit me directly at the bottom of my CCR tek frame, and it pushed me fast. I was under a boat; if I slid, I would have my legs directly in the props. I tried to free myself, but I couldn’t. I was trapped!


"Nath are you OK?"

I couldn’t understand. Was I OK?!

I was stuck under the boat!


The seconds passeds in slow motion. I realised this was my own boat pushing me. I  recognized the sound of the hull of the pontoon against the CCRframe. I didn’t want to slide and reach the props. I asked myself: “Why don’t they stop? Don’t they know I can’t free myself?”


Find the rest of Nathalie’s story in Close Calls. You can order the book here. Fifty-percent of the net proceeds got to DAN Europe’s Claudius Obermaier Fund