Connect with us


How Deep is Deep? The 20 Deepest Tech Shipwreck Dives and How They Compare to Dives in the 1990s



By Michael Menduno

*This article has been updated from this version to the 30 Deepest Shipwrecks and new wrecks have been added after reader feedback.

The advent of mixed gas usage by sport divers—the so-called “Technical Diving Revolution”—in the early to mid-1990s greatly expanded our community’s underwater envelope, while arguably improving diving safety. In order to appreciate how far, err deep, we have collectively come, I thought it would be illustrative to contrast the deepest tech shipwreck dives from today to those in the 1990s when technical diving was just getting started. A similar exercise could be done with cave diving.

Back in the early to mid-90s, technical diving pioneer Capt. Billy Deans, owner of Key West Diver, observed that mix technology enabled us to “double our underwater playground.” Deans was contrasting the then existing recreational diving limits, (i.e., no-stop dives to 130ft/40m) to the new technical diving envelope that was made possible with the use of helium-based bottom gas and accelerated decompression using nitrox and oxygen. Note that during this period, the words “deep” (beyond 40 m) and “decompression”, (i.e., “The D-words,”) were considered four-letter words by many in the recreational diving establishment.

At the time, we considered open water decompression dives with 15-25 minutes of bottom time to depths of 260 ft/79 m to represent a reasonably reliable envelope for technical mixed gas diving operations. That’s what Deans meant about doubling of our recreational playground. Because of the ability to more easily stage bailout and decompression gas in the cave environment, the envelope there was considered deeper/longer. That is not to say that tekkies weren’t diving deeper than 260 ft/79 m and staying longer, but at that time, we considered these dives to be “exceptional exposures”, requiring special methods and work.

Deep Shipwreck Dives in The 1990s

Table 1 below highlights the ten deepest tech wreck dives from 1989-1999, including their location, depth, dive profile, the technology used, and the technical divers who first dived the wreck. The majority of these dives were reported at the time in my magazine aquaCORPS Journal. The deepest dive at the time was the Edmund Fitzgerald at 530 ft/162 m in Lake Superior. The shallowest in the table was the RMS Lusitania at 310 ft/95 m.

Average depth: 398 fsw/122 msw, Avg Bottom Time: 16.7 min Average Run Time: 192 min  

* Note that Tysall & Zee’s dive on the Fitz was essentially a “sneak” dive i.e. they did not have permission to dive the wreck, which was a gravesite, though they laid a plaque on the wreck with the names of the fallen.

** Denlay & Tysall’s first dive in 1995 was to 361 fsw/110msw on the shallow stern of the Atlanta. They returned in 1997/98 where they made their deepest dive to the bow.

** Jacque Cousteau, Albert Falco (team leader), Raymond Coll (camera), Ivan Giacoletto (lights) and Robert Pollio (photo), were the first to dive the Britannic in 1976. Their first recon dive was on air!! Subsequent dives with BT: 15 min were made with Trimix 14/54. The team deco’d in a bell. GUE launched its own expedition in 1999 which included the Lundgren brothers. 

There are several observations to be made. First, all of these dives were conducted on open circuit. At the time, literally, only a handful of tekkies had rebreathers, which were either modified Carleton Mk 15.5s, Dr. Bill Stone’s handmade Cis-Lunar rebreathers, the Halcyon PVR-BASC semi-closed rebreather aka “The Fridge,” the predecessor of the RB80, or various prototypes. AP Diving’s “Inspiration,” the first full-production sport rebreather, would not be released until mid-1997. As a result, rebreather use would not hit its stride for another decade.

Jarrod Jablonski, Dr. Todd Kincaid, and Richard Lundgren planning their dive on the HMS Britannic in 1999.

Two of the dives shown in the table, the Frankfurt (420 ft/129 m) and the Ostfriesland (380 ft/117 m) were conducted by wreck diving pioneers Ken Clayton and Gary Gentile on heliox (an oxygen-helium mix). In 1989, Clayton, Gentile and their team also conducted deep air dives with air decompression—can you imagine??—on the USS Washington (290 fsw/89 msw), which represented the 11th deepest shipwreck dive and did not make the list. Ironically,  even though cave divers quickly embraced “special mix” technology, the majority of serious Northeast U.S. wreck divers were slow to adopt mix technology to replace their deep air diving. However, they did begin using oxygen and or nitrox for decompression.

In terms of divers, Terrence Tysall, now the training director for National Association of Underwater Instructors (NAUI), made the two deepest dives in the 1990s table; the first was while diving the Edmund Fitzgerald with Mike “Zee” Zlatopolsky, the second on the USS Atlanta with Aussie tech pioneer Kevin Denlay. Clayton, Gentile and their teammates accounted for four of the ten deepest wrecks while Gentile was involved with five of the ten, and Deans and his team accounted for two dives on the list.

Note that at the time,  British tekkie Polly Tapson, one of the first female tech expedition leaders, and her team “Starfish Enterprise” captured the imagination of the community with both their preparations and successful dives on the Lusitania in 1994.

Three years later, British tech pioneer and inventor Kevin Gurr launched the first technical expedition on the Britannic with Dave Thompson, founder of JJ-CCR, Al Wright; Global Underwater Explorers’ (GUE) Richard Lundgren; his brother, photographer Ingemar Lundgren; photographer Dan Burton; and British tekkie John Thornton. Of course, the wreck was first discovered and dived by Jacques Cousteau and his team in 1976 (see Table 2).

GUE launched its own Britannic expedition in 1997 with a large team consisting of Jarrod Jablonski, Todd Kincaid, Richard Lundgren, Panos Alexakos, Per Andersson, Johan Berggren, Steve Berman, Ted Cole, Andrew Georgitsis, Joakim Johansson, Sigmund Lundgren, Barry Miller, Tyler Moon, Mikael Ollevik, Anthony Rue, and Bob Sherwood.

In terms of dive exposure, the average depth of these 1990s wrecks was 398 fsw/122 msw, the average bottom time was 16.7 minutes, and the average run time was 192 minutes or slightly more than three hours.

The Deepest Shipwreck Dives Today

Table 2 shows the 20 deepest technical shipwreck dives as of 2018, again identifying the first tech teams to dive on the wrecks. Note that only the five deepest shipwreck dives from the 1990s made it on the new list. The deepest was the mv Jolanda, dived in 2005 by Leigh Cunningham and Mark Andrews to a depth of 669 ft/205 m.

This Table has been updated to reflect new information. View the new table here. 

Average depth: 588 fsw/179 msw Avg. Bottom Time: 19.3 min Avg. Run Time: 366 min 

* The wreck sits vertically from 70-150 msw.

** Scuttled in Operation Daylight, Operation Deadlight Type VII 

***Denlay & Tysall’s first dive in 1995 was to 361 fsw/110msw on the shallow stern of the Atlanta. They returned in 1997/98 where they made their deepest dive to the bow.
A GUE team returned to film a documentary “USS Atlanta, Defender of Guadalcanal” in 2011 and conducted 40-min bottom times with up to 360 min runtimes using RB80s and trimix 8/90. Team: Richard Lundgren, Jarrod Jablonski, Casey Mckinley, Liam Allen, Kirill Egorov and JP Bresser

**** The wreck had been dived previously in September 2000 by Richie Stevenson, Chris Hutchison and Dave Greig but only as a bounce w/ 2 min bottom time.

***** Jacque Cousteau, Albert Falco (team leader), Raymond Coll (camera), Ivan Giacoletto (lights) and Robert Pollio (photo), were the first to dive the Britannic in 1976. Their first recon dive was on air!!  Subsequent dives with BT: 15 min were made with Trimix 14/54. The team deco’d in a bell. GUE launched its own expedition in 1999 which included the Lundgren brothers.

 Viewed from today, the 20th deepest wreck dive is the HMHS Britannic at 395 ft/120m, slightly shallower than the average 400 ft/123 m depth of the 1990s list. The deepest dive in the 90s, being the Edmund Fitzgerald, aka ‘The Fitz” is now #8 when viewed from today. That is to say that nine of the ten deepest shipwreck dives today were conducted after 2000.

Note also that there is one high altitude shipwreck dive on the list: the SS Tahoe, which was first dived by Martin McClellan and Brian Morris at a depth of 471 ft/144 m, and lies in Lake Tahoe at an altitude of 6,224 ft/1,897m. The altitude makes the SS Tahoe a no-man’s land in terms of decompression knowledge; there is almost no data to validate procedures for aggressive dives at that altitude. Only Sheck Exley and Nuno Gomes’ series of sub-500ffw/153mfw open-circuit cave dives from 1992-1996 at Boesmansgat sinkhole, which lies at an altitude of 5,000 ft/1,500m in South Africa, were possibly more extreme.

HMS Curacoa Bridge –  Diver: Stewart Andrews, Photo by Barry McGill.

Twelve of the current deepest shipwreck dives (all five from the 1990s) were conducted on open-circuit while the remainder were conducted with closed-circuit technology. All the dives but one were made using trimix as a back gas or diluent, the exception being the Frankfurt first dived by Clayton and Gentile and their team on heliox as discussed above.

The average depth of the ten deepest shipwreck dives viewed from today is 588ft/179m, a full 188ft/57m deeper than the ten deepest shipwreck dives from the 1990s.

Closed circuit technology is partly responsible for the deeper depths and longer dives we see today. The average depth of the ten deepest shipwreck dives viewed from today is 588ft/179m, a full 199ft/61m deeper than the ten deepest shipwreck dives from the 1990s. Average bottom time for the deepest ten was slightly longer at about 19.1 minutes compared to 16.7 minutes for the 1990s wrecks; however, average run time was 366 minutes and a little over six hours or nearly double, the three hour run times in the 1990s due to the increased decompression obligations.

Irish tekkie and photographer Barry McGill, his colleague Stewie Andrews, and their various teams were responsible for three of the 25 deepest shipwreck explorations. Aussie tekkies Dave Bardi, Craig Challen, Richard “Harry” Harris, and their colleagues from the “Wet Mules,” who were prominent in the Thai cave rescue earlier this year were responsible for two of the deepest wrecks. They also dived on the HMS Victoria three years after Mark Ellyat and Christian Francis. Samir Alhafith and his teams also accounted for two, as did Jeff Cornish, Mark Dixon and their teams. Tysall remained on the list for his dives on the Fitz and the Atlanta.

Note that in 2011 a GUE team consisting of Richard Lundgren, Jarrod Jablonski, Casey McKinley, Liam Allen, Kirill Egorov, and JP Bresser, returned to the USS Atlanta to film a documentary “Return to the USS Atlanta, Defender of Guadalcanal” and conducted 40-minute bottom times using RB80s, with up to six-hour run times using trimix 8/90 as back gas.

Image of the USS Atlanta from the Global Underwater Explorers expedition in 2011. Image Credit: TBD. 

Have we reached our depth/time capability as self-contained divers? If history is any judge, likely not. My long-held belief is that self-contained atmospheric diving systems (ADS) aka Exosuits or hard suits such as those developed by commercial pioneer Phil Nuytten, founder and CEO of Nuytco Research, represent the next wave of technology that promises to extend our envelope even further. However, given the slow pace at which diving technology evolves (it’s a matter of economics), it may be awhile before divers will have access to a $10-$15,000 swimmable Exosuit. Even so, it will be interesting to see what the list of the 10 deepest tech shipwreck dives will look like in 2038. No doubt GUE and others will be there.

Note, I researched these charts over the last two years, but there is missing information in addition to possible errors or omissions. If you find any, please notify me at m2@GUE.com and we will correct them.

Top Image: HMS Curacao deck gun near the break where the Queen Mary struck. In the background – Diver: Stewart Andrews. Photo Credit:  Barry McGill.

Michael Menduno is InDepth’s executive editor and, an award-winning reporter and technologist who has written about diving and diving technology for 30 years. He coined the term “technical diving.” His magazine “aquaCORPS: The Journal for Technical Diving”(1990-1996), helped usher tech diving into mainstream sports diving. He also produced the first Tek, EUROTek, and ASIATek conferences, and organized Rebreather Forums 1.0 and 2.0. Michael received the OZTEK Media Excellence Award in 2011, the EUROTek Lifetime Achievement Award in 2012 and the TEKDive USA Media Award in 2018.


No Direction Home: A Slovenia Cave Diving Adventure

Suffering from Covid lockdown, young, poetic Italian explorer, instructor, and gear-maker, Andrea Murdock Alpini, decided to take social distancing to the max! He packed his specially designed cave-van and set out on a three-week solo road trip to dive the water-filled caves lying beneath the Slovenian soil. His report and must-see video log, dubbed, “No Direction Home”—an homage to Martin Scorsese’s Bob Dylan docu—will likely satisfy those deeper urges for adventure. Did I mention the killer soundtrack? Kids don’t try this at home!




Text: Andrea Murdock Alpini

Photo & Video: Andrea Murdock Alpini

Ecco la storia originale così com’è stata scritta in italiano

Author’s note: I do not encourage other divers to conduct solo diving. The trip and the dives described in this article were conducted after significant training and experience.

Ed.Note: Global Underwater Explorers does not sanction solo diving.


That was the feeling I had last June 2020 when I left my home to begin a journey alone. Caves, abandoned mines, alpine lakes, and a few wrecks—that was my plan for a great adventure.  

The first COVID-19 lockdown had been in place for a couple of weeks, and I was afraid of going out and meeting people. Social distancing left an open wound. I loaded my wreck-van with plenty of stuff to survive alone for a long month traveling amongst rivers, lakes, mountains, and forests, and I was ready to practice scuba diving. 

At that time, tourist travel was impossible in Italy or abroad—anywhere  in Europe—because the coronavirus had locked the borders. I asked an editor in chief from a magazine—one whom I am used to sending articles to—to prepare a couple of official invitation letters for customs. For my trip, I converted my wreck van into a cave van. It was fully equipped with a 300-bar air compressor, helium, oxygen, deco cylinders, twinsets of different sizes, gas booster, fins, mountain boots, tent, camp burner, and brand-new dry suits, as well as thermal underwear to be tested for my company PHY Diving Equipment. 

I remember the day well. I was thrilled as I crossed the border between Italy and Slovenia. I had been restricted to nothing but a 200 m/650 ft walk from my house because of the pandemic restrictions, but with an eight-hour drive, I was free to enjoy walking into wild nature all alone.

The mental switch was awesome, and unexpected. I did make just one phone call from abroad. I talked to an incredible Russian who was the first guy I met in a small rural village in Slovenia. He had emigrated some years ago, and now he welcomed travelers by sharing his farmstead. 

However, once I arrived on site, I was not very welcomed by  the weather; instead, I was met by heavy rain. After the storm passed, I went out walking and filming with my phone. I had decided to record all of the trip. As luck would have it,  the rain returned again, and it never left me for the entire duration of my trip (almost a month).

My tour was articulated throughout Slovenia, Garda Lake (Italy), Austria, and South Tirol’s Alps, Tuscany’s caves, and finally I reached the central part of Italy—Appenini mountains and their peaks. I planned to reach two mines, but heavy rains stopped my dream. Excluding Slovenia, where I slept in a traditional bed, I passed all my time living in my tent. Cold weather and storms were my constant companions. 

I managed to see  a ray of light for just a few hours, I never had any chance to dry my equipment, and I warmed up inside my van. Every night I slept only a few hours because of loud wind noise or strong rain storms. Day-by-day I grew tireder and more feeble. One day, three weeks after I left home, I was in South Tirol descending a mountain when I decided to conclude my trip, and I returned home safe.

The goal of my trip was to tell scuba adventures from the surface point of view where the water is only a part of the context and not the objective. I made a mini-series film composed of three chapters. Each one brings you inside the scene. What  follows here is the first episode of the trip.

Social Distancing Beneath The Slovenian Soil

The first day of cave diving in Slovenia was very tricky and full of adventures. I had no idea how the second day would go. 

I left my accommodations around 6 a.m., after a good breakfast of cereal, dark chocolate with black coffee, dried fruit, and tasty Italian Parmesan cheese. I could not see anything from my window because what had fallen was not simply rain; it appeared to be an awesome flood. My plan for that day had been delayed.

I think that most parts of dry caves are condemned for hundreds of kilometers. So, I decided to check the weather forecast and water level conditions in caves close to the Croatian border. It would mean driving about four hours to see for myself whether scuba diving was allowed. I didn’t have to remind myself, I was alone here.

Wheels were on the road and local conditions seemed quite good. I had checked the weather on my laptop and understood the risk. If I was lucky, I could dive; if not, I would have to drive back. I drove through Slovenia forest meeting no one. With less than an hour left to my destination, I came across an abandoned farm village, completely empty.

The dive inside Bilpa Jama was breathtaking. Now I was seated beside the cave shore preparing soup to warm myself. After a stunning solo dive, I was cold and wanted only to taste the peace of this magnificent place. While I was dipping  the spoon in my soup cup, I heard a faraway voice, a police woman calling me and asking me to stop eating and come quickly to her. 

After I did as I was asked, she started examining my passport, documents, and permissions. A few minutes later, a huge National Army truck reached us. The soldier had  an abnormal body shape, a man the size of a walking mountain in an Army uniform. Can you imagine how I was feeling in those moments?!

Well, in the end, everything went really well, and I now have a story to tell my grandchildren. 

Once the passport control was over, and they had checked that I did not cross  the border from Croatia to Slovenia illegally (customs was only a few hundred meters  from us), I had the chance to get back to my soup, which by then had turned cold. I warmed it up again, and I spent half an hour seated on a slippery stone covered with moss and lichens watching the beauty of the forest surrounding me.

On the way back to my accomodations in my cave van, I  played a new playlist. 

Four hours later, I approached my country lodge. I was really exhausted,  but I had to refill tanks and plan the next scuba diving days. Once I finished, I watched the forecast again. Unfortunately, it was growing worse, so I decided not to dive and instead get a surface break. Tomorrow I would drive, search, and catch info and GPS coordinates of caves. My tomorrow plans had turned into a sketching and surveying day. 

The Road To Suha Dolca 

I drove and walked for hours and hours, up and down the forest or on lonely roads in search of caves where I could return in winter or perhaps next year. During the last survey of the day, I watched a talented young guy playing a traditional concertina and thought, what a lovely atmosphere and a fitting way to close my hard-working day!

I decided to give a last gaze to Suha Dolca cave, my favorite one, on the way home. This was the third consecutive day I had arrived back at this spot. Observing it day-by-day, I tried to find the best moment to dive this cave.

Until now, it was inaccessible due to the strong flow. I wanted to dive here before leaving Slovenia. Tired and  driving slowly, I parked my van away from my accommodation. Since I had no lunch, I started feeling very hungry. A simple dinner was quickly served: dried fruits and a cup of hot noodle soup.

My ‘NO DIRECTION HOME’ trip was now at its peak. I had become a wanderer. I was alone in a wild country with, yes, an internet connection for historical research and checking the weather. That was the only technology I used. Aside from that, I lived simply. I walked, dived, wrote, and filmed my experience all with my mobile phone.

Rain was tougher than expected. I had hoped to stop for one day, not the two that it took. Following the surveys, the next day I started fixing my video equipment and saving photos and videos I had made on my hard drive.

I had too many ideas, no one clear till the end, and too many cave sketches and GPS points to reorganize; I needed a day to regroup. I just went out for a few hours to check Suha Dolca’s Cave conditions. On this day it seemed that the flow was getting more stable, and general water conditions were growing better. I had to be patient and wait one or two days more for the right conditions. I tried and failed to find a solution on my own, but the water always showed me the way. She told me to wait and to go back to where I came from. Step-by-step I walked the path again.  

The third video chapter of Slovenia Solo Cave Diving is the one I prefer, because I remember the indecision I felt, to stay or to leave. Solo trips are strictly linked to life’s decision.

The last day I was in Slovenia I left the accommodations and asked a new farmer, close to a different cave, if I could sleep inside his barn and dive the river hole on the following day. I was at the same place where I had dived the first day. He told me I could not stay in the barn due to the high risk of bears who live in the surrounding area. I jumped in my van again and I drove to the lake beside Suha Dolca’s Cave. 

I descended the path several times and brought all my scuba gear piece-by-piece. I decided to give myself a chance to dive my dream cave in the late afternoon. I had no other choice. Once I was inside the cave it was unbelievable, and I had a very nice dive even though I was really tired, and again I broke my light arms and camera housing. I resurfaced after the dive into a reed’s lake, which made me feel like a beaver.

I had conflicting feelings as I left Slovenia that same night after making a tricky and stunning dive. Bears, awesome forests, and rural areas were now all behind me. The cave-van played a new disc, I needed to shake off these feelings and look forward to my new goals: Garda Lake’s wrecks, South Tyrol’s stunning lakes, and finally Austria. In the country of green and wide grazing land I wish to dive surrounded by the amazing scenario of beautiful Alps mountains. 

At 9:30 PM I crossed the border again, and  Italy was straight ahead.

Andrea Murdock Alpini is a TDI and CMAS technical trimix and advanced wreck-overhead instructor based in Italy. He is fascinated by deep wrecks, historical research, decompression studies, caves, filming, and writing. He holds a Master’s degree in Architecture and an MBA in Economics for The Arts. Andrea is also the founder of Phy Diving Equipment. His life revolves around teaching open circuit scuba diving, conducting expeditions, developing gear, and writing essays about his philosophy of wreck and cave diving. Recently he published his first book entitled, Deep Blue: storie di relitti e luoghi insoliti.

Continue Reading

Thank You to Our Sponsors


Education, Conservation, and Exploration articles for the diving obsessed. Subscribe to our monthly blog and get our latest stories and content delivered to your inbox every Thursday.

Latest Features