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Searching for Underwater Mines in the Adriatic

Unexploded naval mines are still a thing in the Adriatic. Authorities estimate there might be as many as 5000 of these deadly devices remaining in situ from past wars. Less one! Former Croatian police diver turned tech diver Velimir Vrzic reports on discovering a German EMC type II just off the city beach in Rijeka, Croatia, with teammate Aleksandar Stančin. Find out what happened and what they found out!



By Velimir Vrzic
Header photo by
Aleksandar Stancin.

This project, titled Project UMS (Underwater Mine Search), was initiated by GUE divers from Croatia along with members of the local club “Policeman Diver.” Joining our efforts with active police divers from the Croatian Special Task Force’s Bomb Squad, our goal was to help locate, document and record using 3D photogrammetry, lost naval mines from WWI and WWII so they can be defused and removed. Authorities estimate there are as many as 5000 naval mines from the two world wars that still remain in the Adriatic sea. 

Mining The Main Rijeka Beaches 

During the last days of December 2019, while the citizens of Rijeka, Croatia, were preparing for New Year’s Eve, my dive buddy and I discovered something that we did not expect to see—an abandoned naval mine of great destructive power during a routine exploratory dive. The mine is laying on the bottom at a shallow depth of 25m/82ft near the Rijeka city beach, which has been frequented by citizens and tourists over the last 80 years. Please note, #Redbull doesn’t really give you wings, but finding one of these does!

German UMB Naval mine (Rijeka Croatia).
Photo courtesy of Aleksandar Stancin.

Rijeka is a city of turbulent, dynamic, and troublesome history and recently, it has been designated the “European Capital of Culture” for 2020. Over the ages, various military forces marched through it, always bringing fear and leaving destruction behind. During the last 100 years of its rich history, Rijeka has flown seven national flags. As an important geostrategic city in the Adriatics, it is always a location of interest. 

We located the mine near an elite beachfront area of Rijeka near the Villa Olga approximately 20m/65 ft from the shore. The villa used to be a command post of Nazi Germany occupying forces after Italy switched sides in WWII. The reality of this can still be seen from the SS insignia as well as a swastika on the villa’s fence.

The fence at Villa Olga today. Photo courtesy of Aleksandar Stancin.

However, it is not the villa or the fence that can do harm now, unlike the mine which rests just offshore. Based on our research, the mine was deployed sometime from 1943-1945 to protect the coastline from a possible Allies surprise seafront attack. My fellow diver and photographer Aleksandar Stančin was able to confirm it is an EMC type II naval mine, containing up to 250 kg, 551 pounds of TNT, which makes it more than capable of damaging and sinking a ship. 

It could easily damage or destroy local sewers and or seriously hurt swimmers if it detonated regardless of the fact it is lying in 25m/82 ft of water. Of course, we immediately reported our discovery to the local authorities who brought in a special police task force (underwater unit) from Zagreb to confirm the finding of an active naval mine. Ironically, nearby the mine, there were several artefacts from the beach, including a child’s diving mask, flip flops, and several other items. 

By a twist of fate, this mine and many others were laid by a ship called Kiebitz under Nazi Germany. The ship, which was basically a banana cargo ship originally named Ramb III, was acquired when Italy changed sides and Germany took control of the area. Ironically, the Kiebitz sank in the port of Rijeka during an Allied raid at the end of 1944, when it made contact with one of the mines she had deployed. 

 German (WWII) minelayer the “Kiebitz.” 
Photo courtesy of

After WWII, the Kiebitz was salvaged and restored to seaworthy status, but this time with a different role. The ship, renamed The Peace Ship Galeb, became a symbol of peace in Josip Broz Tito’s Yugoslavia when he traveled and hosted political meetings and events on the ship.  The Galeb is currently being renovated as a part of the European Capital of Culture project to serve as a museum of those times.

Additional Resources: 

X-Ray Magazine: Clearing Mines in the Sava River of Bosnia
NAV Weaps: German Mines

Born in 1972, Velimir Vrzic started diving at the age of 17 as part of the C.M.A.S. Federation in Yugoslavia. After Croatian independence, he joined the police force from 1991-1995 and was decorated by the President of Croatia three times for his military operations and service to the country. After the war, back in the maritime police, Velimar worked as a crime investigator at sea. After completing an anti-explosives course, he performed special jobs for the Ministry of the Interior. He then met his future dive instructor, Mario Arena, and joined the GUE. In 2012, Velimar underwent heart surgery to close his open PFO (patent foramen ovale). In 2013, at the age of 40, he retired from the police force and opened a non-profit diving club called Policeman Diver. The organization works with state agencies to protect the sea in Croatia. He is also co-founder of the cave project “Morpheus.” Velimar is happily married to his wife, Pamela Vrzic, who is also a diver.


Undergoing PFO Surgery as a Team: Deana & Bert’s Excellent Adventure

People like to give GUE a hard time for their uncompromising focus on team diving. But a pair of divers from GUE Seattle has taken it to a new level: getting their PFOs fixed together. The team that bends together, mends together? Instructor and tech diver James D. Fraser willingly tells the tale.




by James D. Fraser
Header photo courtesy of Dr. Doug Ebersole

This is the follow-up to the story that ran in InDepth December, 2019: No Fault DCI? The Story of My Wife’s PFO

It has been a year since my wife Deana had a decompression illness (DCI) hit in Bonaire requiring her to do a Table 5 recompression profile in a hyperbaric chamber. At the time of my previous article’s publication, Deana had a Transthoracic Echocardiogram (TTE) bubble study and found out she did have a small to moderate patent foramen ovale (PFO). Two physicians offered similar options for Deana to consider when it came to her diving activities: 

  • Stop diving, as this eliminates any risk of DCI in the future.  
  • Modify her dive profiles to be more conservative: diving only once per day, diving nitrox 32 using air tables, and/or extending her decompression profiles and safety stops.
  • Have the PFO repaired, knowing it is not a guarantee, and continue diving as conservatively as possible. 

Deana had initially decided to wait on doing a PFO closure until after our daughter’s wedding in March 2020, but she realized very quickly that being “conservative” was not in her nature. Deana had already returned to diving within 12 days of her hyperbaric chamber ride. In the 46 days since her treatment, Deana had already done another 15 dives to depths of 90 feet; being conservative really was proving to not be an option for her. Diving was just too much a part of her life. 

Deana with Dr. Ebersole. Photo by D. Ebersole.

In mid-November, Deana reached out to cardiologist and tech diving instructor Dr. Doug Ebersole for a second opinion on the bubble study and his advice about her options. Dr. Ebersole gave Deana the same response as the other physicians; but, knowing Deana and her passion for diving, he suggested that she have her PFO fixed, since her plan was to continue diving. 

Deana also spent time talking to other divers who had been diagnosed with PFOs—some who had them repaired and some who had decided against it—in order to get a more complete picture from both a patient and a doctor point of view. One of the final conversations that pushed Deana to have her PFO repaired was with a coworker who was a nurse practitioner in cardiology with knowledge of PFOs and diving. Her coworker was pretty blunt, stating, “Why are you playing Russian Roulette? You have worked in cardiac and know the risks.” 

Some of these risks include Arterial Gas Embolism (AGE), Venous Gas Embolism (VGE), and cerebral embolism. That was the final “Aha” moment to tip the scale and get Deana to schedule her PFO repair, since “Russian Roulette” was exactly what Deana was doing based on her diving activities following her DCI hit.

Team Approach to Treatment 

Bert Berzicha, one of our GUE Seattle community members, also completed his TTE as a result of having had some symptoms of DCI in the past. The test confirmed the presence of a large PFO. Deana and Bert compared notes initially and discussed diving as a team on future dives using more conservative decompression profiles than other teams, allowing the other teams to get out of the water sooner. Deana, however, related what she had learned from talking with her coworker and changed her mind about diving conservatively and instead decided to get the PFO repaired. 

Bert and Deana with some of the GUE-Seattle Tech crew. Photo by Bert Berzicha.

Deana did not want to take the risk of neurological deficits that could be irreversible. Deana suggested to Bert that he come with her to have his PFO repaired at the same time. Bert continued to research the subject, looked at his work schedule, and decided doing a “team” procedure made sense. Just as a dive team shares a plan, resources, and emergency procedures, a medical procedure shares similar benefits when working as a team. 

It was time to plan a date for both of them to have the procedure. Deana and Bert both live in the Seattle area. Dr. Ebersole lives in Lakeland, Florida, so logistics included time off work, pre- and post-surgical care, flights, hotels, and transportation. Deana arranged to have her sister Jessica fly into Tampa from Dallas, prior to them arriving, so she could pick them up from the airport to make it to the hospital in time for the procedure. I was going to be in Australia on a business trip at the time, so I was not able to be there pre-surgery. I ended up reworking my return trip and flew from Canberra, AU to San Francisco, then on to Tampa, to land just an hour after their surgeries were finished and meet them back at the hotel. 

Even though Deana and Bert could fly home 24 hours after the procedure, they decided to stay the weekend just in case there were any complications and to take it easy. Deana, however, had a different take on “easy.” The morning after surgery, Deana was invited by Dr. Ebersole to watch a procedure that he and his team perform called the “WATCHMAN” procedure (less than 24 hours after post-op). Then we picked up Bert and Jessica, and jumped into the truck to do a 300-mile, five-hour road trip to High Springs, FL, to take a tour of the Halcyon facility and say “Hi” to Orie Braun, Lauren Fanning, and Mark Messersmith; stop in at Global Underwater Explorers (GUE) HQ to buy some swag; and drive down to Ginnie Springs to see where Cave 1 may take place in Deana’s and my near future. Not bad a day after surgery. 

Deana and Bert after surgery. Photo by James Fraser

It was at Ginnie Springs where Bert came to Deana and stated he thought he had active bleeding. We all paused and turned pale, knowing we were not in a great location for this to be happening, but after being assessed by Deana it turned out to be post-op bruising from the surgery. This did, however, make us stop and think, “We just drove 300 miles away from the hospital we had decided to be close to in case of complications.” I am sure Gareth Lock would find a really good human factors story in there somewhere. 

Deana’s PFO adventure Timeline


  • OCT 8: 47 m/153 ft technical dive resulting in a DCI episode requiring recompression.
  • OCT 20: First dive post-chamber ride to 16 m/52 ft
  • OCT 29: TTE Bubble Study; “Deana has a small to moderate PFO”
  • NOV 17: Dr. Ebersole receives Deana’s TTE study for a second opinion 
  • NOV 21: Deanna dives now to 28 m/90 ft
  • DEC 4: Last dive before PFO repair. In the 46 days since her hyperbaric treatment Deana made 15 dives: “Conservative Not”
  • DEC 12: Deana and Bert have PFO procedure
  • DEC 13: Lakeland to High Springs road trip


  • JAN 27: First dive post closure—15 m/49 ft and spaced dives 2-3 days apart
  • FEB 15: Started doing multiple dives daily no greater 15 m/50 ft
  • MAR 8: PFO follow-up; OFFICIALLY cleared by Dr Ebersole to dive
  • MAY 7: Dives now pushing 30 m/100 ft
  • MAY 31: First Tec dive to 33 m/110 ft 

Since May, Deana has done 120 dives in 2020 with a max depth of 52 m/170ft, which she did on September 12. Deana has gone back to no-restriction diving and has completed 16 technical dives since this summer. Some of these have been assisting with photogrammetry dives.

  • 46 m/150 ft to 52 m/170 ft: 3 dives 
  • 40 m/130 ft to 46 m/150 ft: 5 dives 
  • 30 m/100 ft to 40 m/130 ft: 8 dives 

Getting Personal With PFOs

COVID-19 has prevented us from doing a dive trip this year, which is the one main test we still have yet to do: repeat the scenario that always led to her getting DCI, which was three consecutive days of recreation and tech dives, to see if she experiences any recurrence of DCI symptoms. 2021 will hopefully open up this opportunity, or by that time Deana will already be training for GUE’s Tech 2 course. In either case, Deana and Bert are both very happy to have had their PFOs repaired; both have seen improvements in their health in other areas such as endurance, no longer being easily winded, and, in Bert’s case, less headaches, which he had prior to the PFO closure. 

James, Deana and Bert. Photo courtesy of James Fraser.

To get a PFO repaired is a personal choice, and no one should ever take surgery lightly as it has its own risks. Divers with PFOs need to do their own research and consult an interventional cardiologist, such as Dr. Ebersole, who understands diving. Only then can they make an informed choice based on their own unique situation whether or not a PFO closure is right for them. This article is meant to show the process and outcome of two very experienced and ambitious divers who made the choice to have their PFO repaired and the results of that decision.  

(PFO) Free At Last! Deana after completing her first dive to 52 m/170 ft in Lake Crescent, WA diving the Warren car. Photo by Bert Berzicha

Additional Resources

Diving and Hyperbaric Medicine: The effectiveness of risk mitigation interventions in divers with persistent (patent) foramen ovale  by George Anderson, Douglas Ebersole, Derek Covington and Petar J Denoble. 2019 Jun 30.

Alert DiverPFO Study Update by Petar J Denoble

Alert Diver: Cases studies of divers who had their PFOs closed with transcatheter-applied occluders: Divers with Holes in their Hearts by Petar J Denoble 2010

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James D. Fraser is a GUE Fundamentals and Rec 1/2 Instructor, PADI MSDT, and NAUI Scuba Instructor, and has been diving in the Pacific Northwest for over 30 years. James currently lives in Seattle, WA, with his wife and dive teammate Deana Fraser. As a member of the GUE Seattle Board of Directors, James is able to share his experiences and work with Deana at growing the local diving community sharing their passion with all who are interested. James recently embraced technical diving, becoming certified as a Technical 1 diver with GUE. James and Deana have had opportunities to travel all over the world to experience their passion in amazing places such as Egypt and the Maldives. James currently works as a Cyber Security Director with a Fortune 500 Defense Contractor and has been a residential construction business owner and Emergency Medical Technician (EMT). 

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