By Martin Cridge
Header image of the IJN Nagato and other historical images courtesy of Dirty Dozen Expeditions.
Full Disclosure: Dirty Dozen Expeditions is a sponsor of InDepth.
Admiral Isoroku Yamamoto, Commander in Chief of the Japanese Combined Fleet had been awake since 2 a.m. on his flagship the IJN Nagato, anxiously waiting news on the Japanese attack on Pearl Harbor. Suddenly, the now infamous code word was excitedly shouted down the voice pipe from the radio room. ”Tora Tora Tora!” meaning that surprise had been achieved and the attack was a success.
Earlier, that same radio room on the Nagato had transmitted coded message number 676, “Niitakayama nobore (Climb Mount Niitaka) 1208” to the Japanese Strike Force (Kido Butai), which was then around 1513 km/940 miles north of Midway and steaming towards Hawaii. Mount Niitaka, located in Taiwan, was the then-highest point in the Japanese Empire, and the message meant that hostilities would commence against the U.S.
The Nagato was laid down at the Kure Naval Arsenal on August 28,1917, launched just over two years later on November 9, 1919, and commissioned just over a year later on November 25, 1920. The ship incorporated a number of technological advances for the time, which were developed by the Japanese, and when she entered service she was the world’s largest and fastest battleship.
The Nagato was the first Capital ship in the world to be fitted with 16-inch guns. The eight guns were arranged in four twin-barreled turrets, two forward and two aft. The ship was extensively modified and refitted in the 1930s. The most striking modification was the fitting of a Pagoda mast. Pagoda masts were common on Japanese ships of the time; they had a number of platforms, lookouts, and shelters built upon each other and included watch points, searchlights, rangefinders, gun directors, and spotting points. The end result often resembled a pagoda temple, hence the name. Her displacement also increased at the same time to 39,130 tons and her length to 224 m/734 ft.
The Nagato was the only Japanese battleship to survive the Pacific War. Lack of fuel and materials to repair her meant she saw out the last months of the war as a floating anti-aircraft battery at the Yokosuka Naval Base. The Nagato was purposely taken over by US Navy personnel on August 30, 1945, before the official Japanese surrender was signed on board USS Missouri a few days later. The US Navy said this symbolized the unconditional and complete surrender of the Japanese Navy. After being selected for Operation Crossroads—the atomic tests at Bikini Atoll— preparations were made to get her ready for her final voyage. While no one at that time knew what the outcome of the atomic tests would be, it was always going to be a one-way journey for the once mighty Nagato.
She was in a very bad state of repair, having been seriously damaged before the Japanese Surrender. Patched up, she left Japan on March 18, 1946, along with the Japanese cruiser Sakawa, which would also be one of Crossroads’ victims. With only two of her four propellers operational, the Nagato could barely manage ten knots. During the voyage, due to previous battle damage and a lack of maintenance, the Nagato started shipping water into her forward compartments. Her pumps couldn’t cope, and stern compartments had to be purposely flooded to maintain the ships stability. Ten days into the voyage the Sakawa broke down and the Nagato attempted to take her in tow, but then the Nagato lost one of her own boilers and, low on fuel, both ships ended up drifting helplessly in the mid-Pacific. To help, two Navy tugboats were dispatched from Eniwetok, and the Nagato was taken in tow by USS Clamp.
The Nagato continued to ship water, developing a seven degree list, meaning she could be towed at only 1 knot. The Nagato finally arrived in Eniwetok on April 4th, where emergency repairs were carried out and the flooded compartments pumped dry. The repairs enabled Nagato to steam the last 322 km/200 miles to Bikini under her own power and on to her date with destiny. For the Able test of Operation Crossroads, the USS Nevada was the target ship and the Nagato was moored less than 400 m/1312 ft away on her starboard side, well within the expected fatal zone. The Able bomb, however, missed the Nevada, and the Nagato escaped relatively unscathed, suffering only minor damage. For the Baker test the Nagato was once again placed well within the expected fatal zone.
The Nagato, however, rode out the tsunami of water that hit her following the explosion and although she was displaced almost 400 m/1312 ft from her original position, apart from a list to starboard again she appeared relatively unscathed. However, like the other survivors of the Baker blast, the Nagato was now seriously contaminated with radiation. Some minor attempts were made to wash the radiation off her decks, but she wasn’t re-boarded and she gradually settled in the water over the next few days. As the sun set on Bikini on July 29th, the Nagato was still afloat. Her list was now ten degrees and her stern so low in the water that waves were washing over parts of the main deck, although she didn’t appear to be in imminent danger of sinking. Whatever the future held for the Nagato, she wasn’t leaving Bikini. She had survived the two atomic tests but was now seriously radioactive. Having seen the media fanfare as the USS Saratoga slipped under the waves a few days before, the Nagato decided she would go silently, without fuss, without attention. During the night her stern dipped deeper in the water, she rolled over and settled down on the seabed 52 m/171 ft below.
As the sun crept up behind Bikini Island the following morning, the Americans on Bikini gazed out at the empty spot in the lagoon which the Nagato had occupied the day before. She had gone.
Diving The Nagato
Diving the Nagato today, it soon becomes evident that everything about this vessel is big, and even after multiple dives, divers can barely scratch the surface of what the Nagato has to offer. Most dives start on the stern as the main mooring on the wreck is attached to one of the four propeller shafts. The first thing that comes into view are the four massive propellers that once drove the Nagato to 25 knots or more. These are now facing towards the surface, and behind them sit two large rudders.
Being over 4 m/13 ft in diameter, these are certainly impressive, but most divers quickly bypass these, leaving them for exploration towards the end of the dive. Like most battleships, due to her heavy topside weight, she turned turtle before sinking to the seabed 52 m/171 ft below. It appears the stern hit the seabed first, and the stern section of the ship has now broken away behind the rudders and lies collapsed down on the seabed.
The once-mighty 16-inch guns haven’t fallen away from their mounts and are still in their turrets in the stowed fore and aft position. The bow guns still have their end caps in place on the muzzle, but the stern guns don’t enable divers to peer down the inside of the barrel. Sitting as they do in 50 m/164 ft, just exploring the aft guns and propellers can take up almost an entire dive.
Heading towards the bow from the stern, you eventually come to the huge Pagoda mast. The end of the mast broke away as it hit the seabed and now lies out to the right hand side of the vessel and divers can still see the various upper levels, which included spotting points, rangefinders, and gun directors. Look more closely you can see voice tubes and remains of the lift than ran up inside the mast.
Forward of the Pagoda mast you come to the bow guns. Depending on your dive plan, you might not have much time to explore the bow area, as it’s a 200 m/656 ft swim back to the mooring line. One option is to be dropped on the mid-ships mooring by skiff or do a free descent on the bow—that said, most divers still choose to swim from the stern as there is lots to see on the way and lots of nooks and crannies to explore.
Another option is to take a scooter; needless to say, scootering around the Nagato is a fantastic way to experience the wreck. If decompression starts to build up, one can come onto the top of the upturned hull, which stretches for as far as the eye can see, becoming an artificial seabed.
Turtles are often seen on the Nagato as well, and will often swim alongside divers. Due to the lack of human interaction in Bikini, they are far less skittish than turtles found elsewhere. For those who desire it, there are options for penetration both at the stern and bow as well as in the mid-ship sections of the ship.
Care needs to be taken, however, if one does decide to enter the wreck, as there are many old and discarded lines—some which lead into areas that have since collapsed. Any serious penetrations should be planned properly and with the appropriate temporary lines laid. For most divers, there is enough to see on the outside of the wreck and the Nagato is an often requested repeat dive in Bikini.
On the way back, observant divers will notice sharks and other sea life coming into the cleaning station halfway back to the mooring. In fact, the Nagato is a good place to see sharks in general. Normally, there are many grey reef and black tip sharks, and occasionally silver tips—and don’t be surprised to be sharing your deco time with a tiger shark or two swimming around you.
Without Martin Cridge, The Dirty Dozen Expeditions wouldn’t exist. A few years back, Aron and Martin spent a full year diving together in Truk Lagoon. One evening, after a day of demanding dives, they sat, had a beer, and came up with their ideal CCR wreck dive itinerary.
The first-ever Dirty Dozen trip was the result of that beer, and the rest is history. Martin has lived in Truk for eight years with his family and works as the skipper of our expedition vessel in Truk and Bikini.
Über-deep with Cave Explorer Xavier Meniscus
Xavier Meniscus is one of a handful of elite cave explorers who consistently push sub-200 meter plus depths; he holds the record for the deepest cave dive. To accomplish these dives, the former French military and commercial diver utilizes three rebreathers, and is known to possess unusual physiological tolerances that have allowed him to exceed limits without adverse consequences. InDEPTH chief Michael Menduno reached out to Meniscus to discuss his penchant for exploration and his unique approach to cave diving.
By Michael Menduno, with help with translation by Didier Drageuiev. Photos courtesy of Xavier Meniscus.
Fifty-five year old French cave explorer Xavier Meniscus is one of a handful of elite divers making sub-200 meter cave dives and holds the record for deepest cave dive at 286 mfw/938 ffw, which he conducted at Font Estramar in 2019. Meniscus, who was trained at the Institut National de la Plongée Professionnelle (INPP) in Marseille, is a former army combat diver, and a commercial saturation (SAT) diver with COMEX. He started cave diving in 2000, while still a SAT diver, and has explored many caves around the world such as the Goul de la Tannerie in France, the Pozo Azul in Spain, and Boesmansgat in South Africa. Meniscus is also a cave diving instructor with the Fédération Française d’Etude et des Sport Sous Marin (FFESSM). Meniscus recently published a book on his cave exploration work, Les mysteres de l’eau en pays Gervanne entre l’emergence de Bourne et les Fontaigneux, [Translation:The Mysteries Of Water In Gervanne Country Between The Emergence Of Bourne And The Fontaigneux], which is available in French. InDEPTH sat down with the ardent French explorer to discuss his approach to deep cave exploration. Here’s what he had to say.
InDEPTH: Xavier, I would like to discuss your record deep dive to 286 meters at Font Estramar, but before we do, I would like to get a little background on you and your diving. How many sub-200 meter dives have you conducted?
Xavier Meniscus: I have done more than 2,000 hours of rebreather diving in caves and have made around 50 sub-200 meter dives.
Amazing. What is it about deep diving that you find alluring, that draws you?
Mike, it’s not the depth. The depth doesn’t matter. There is no specific target. My goal is to explore and to find what is behind the next cave, and the next. That’s the only thing that matters. There is no sense to go deeper just for the record. If you go deeper, if you take risks, it’s for exploration. Because exploration matters, and the record—it doesn’t matter. It’s completely not the point. This is the reason why I don’t want to have the Guinness record. It doesn’t matter for me. My motivation is exploration.
That’s good. I understand. How do you manage the challenges and risks on deep sub-200 m cave dives? How do you prepare yourself?
I have been a military diver and commercial diver, a saturation diver working with COMEX, and have worked with researchers and hyperbaric doctors, and so I have specific knowledge and understanding of the phenomena and risks. So, because of this knowledge and experience as a professional diver, I have constructed my own decompression and diving procedures.
About the risks, as a military diver I am very, very rigorous about following procedures. I prepare and think out everything step by step ahead of time in order to be very precise on the dive. And it doesn’t matter if it’s a 50 m/164 ft dive or a 200 m/656 ft dive, I follow the same checklist and procedures.
Yes, that makes perfect sense. There is little or no margin for error.
I’m very rigorous, and I review all the aspects of the dive before-hand and review them in my mind as I am conducting the dive. Okay, step one is here, I check this. Step two, I check that and then I continue. And of course, there is always the awareness, call it adaptation to the depth and the cave, of where I am, and what is really the most dangerous thing specifically in the moment. I try to keep all the specific things in mind as I proceed.
Let’s talk about your equipment. I understand that you use a triple rebreather.
That’s right. I took an example from famous cave explorer Olivier Isler, who had been diving since the 1990s using a triple rebreather. I worked with Frédéric Badiér, who had designed a homemade semi-closed recycler called Le Joky. I worked with him to modify the unit to a mechanical closed circuit rebreather with a constant mass flow at 0.7-0.8 liters per minute flow. It’s a very simple unit with a 2.5 kilo canister, breathing bag in the central part of the rebreather with a mechanical KISS valve. The unit has three sensors connected to a Divesoft dive computer. It’s a basic rebreather.
And you use three of them. How do you position them?
I wear two rebreathers on my back—one on the left side, the second one on the right side—and one on the front. The recyclers are the same, exactly the same. I breathe on one, the second is a spare and there’s a third in case I have problems during decompression. So, I can switch from the first, second or third one if I need it. There are interchangeable connections for oxygen and diluent of course.
My protocol is that I only use my main rebreather. I test my second rebreather at strategic points during my dive, for example before leaving, before the deep or narrow zone. The third rebreather is placed at the safety landing, connected to its diluent. The dive computer of my second rebreather has the PPO2 display permanently displayed and I take a look at it very regularly. If it was not waterproof, it would fill with water and become negative, so I would notice this and stop my dive. Also, on long dives, I switch to my second rebreather after 9-10 hours. The third recycler is always just the security. Which is really the worst case, you know.
So, you always dive them as a trio?
When dives are extremely long and very demanding, having three rebreathers is essential. When the dives exceed 7-8 hours, I take a third rebreather.
And just to clarify, the units are all independent. They are not connected by a bailout valve (BOV) or other means.
No, it’s completely independent; there is no connection between the left and right rebreather and there is no BOV as well. It’s just a simple mouthpiece. So if you want to switch to the second one, you turn off the first one and you go to the second one. You need to do that manually.
Have you ever had to bail out on a dive for real on your rig, and how was that?
I only had to use my social security recycler once. It was at Baume des Anges. When crossing an inter-siphon, I dropped my main recycler. The counter lungs were damaged, and when passing the next siphon at a depth of 100 m/328 ft, my rebreather filled with water. I was then forced to return with my safety rebreather.
Gotcha. And just out of curiosity, do you wear a rebreather safety strap i.e., a ‘gag’ strap?
Yes, I’m a former military diver. It’s completely mandatory for us, even for a dive of three meters, you know. This thing can save your life. This is clear.
I understand that you run your oxygen levels very high on your rebreather. Talk to me about that.
During my descent, I keep my PPO2 (partial pressure of oxygen) at 1.4, just to have a little margin if I descend very, very quickly, in order to not completely blow up the PPO2. After the descent, I try to keep my PPO2 at 1.6 for the entire rest of the dive.
Wow, that’s surprising! Why do you run your oxygen that high? I mean, it might decrease your decompression obligation, but aren’t you worried about getting a CNS toxicity hit and convulsing?
So, first of all, I tolerate the high oxygen pressures very well. I haven’t any issue with that. My experience as a military and professional diver taught me, step by step, what the human body is capable of and that my body tolerates high levels of oxygen.
[Ed. Note: Do NOT Try This at Home!!! The overwhelming community consensus is to maintain PO2s below 1.6 atm during the working portion of the dive, and the trend has been towards lower oxygen levels, particularly on big dives. GUE for example, sets its maximum at 1.2 atm during the dive with the option to manually boost PO2s to 1.3-1.4 during shallow decompression. CNS oxygen toxicity convulsions have been recorded at PO2=1.4, and can occur at PO2s less than 1.4 atm in the presence of heightened CO2, which occurs when gas density is high, whether or not it is felt by the diver. Susceptibility varies among individuals and within the same individual at different times. There’s no evidence that tolerance to oxygen toxicity can be improved through practice.]
You may have a high tolerance. But do you ever worry that you are just lucky, and one day you might convulse? Have you ever had an oxygen convulsion?
I’ve never had any toxicity or convulsions with oxygen. My longest exposure was a dive lasting over 13 hours during my last exploration of the St Sauveur chasm in 2013. At that time, we weren’t using a double DPV or taking into account the PPO2 measurement from my computers. I did a total of nine hours at 1.6 bar and the last four hours at 1.9 bar in a bell at a depth of 9m/30 ft.
It’s true that when I came out of the water, my lungs were burning a bit for several hours but it disappeared the next day. To avoid too much oxygen toxicity, I take ‘air’ breaks after seven hours of diving, and breathe air or bottom mix for 5 minutes every half hour.
Do you worry that others will try to follow your example and run their working PO2 setpoint at 1.6 and get hurt? I’m sure you know that PO2=1.6 is outside of current accepted community practice except possibly during shallow water decompression, particularly for CCR. What are the standards for oxygen levels in the Fédération (FFESSM)? What do you teach your students?
In France, we recommend a PPO2 of 1.4 for progression [the working portion of the dive] and 1.6 for decompression. That’s what I teach. The use of high PPO2 for me is a necessity at the depths I go to in order to reduce the inert gas load and limit my very long decompression times as much as possible. It’s an approach that I’ve validated through my training, my long experience and my personal physiological resistance. It is also obvious that on such extreme dives, we push the sliders to the maximum.
[Ed.note: According to V-Planner calculations, boosting PO2s to 1.6 during the working portion of a 286 m dive for a 22-minute bottom time vs maintaining a PO2=1.0-1.3, results in some, but not a significant decrease in overall decompression time. It does however greatly increase the risk of CNS oxygen toxicity. ]
I understand. How deep you run your END (equivalent narcotic depth)? I understand you are using trimix.
I always use trimix with a high level of helium. I maintain my equivalent narcotic depth to around 30 m/100 ft. I always keep a little nitrogen fraction into the mixture and do not use a pure heliox because of the high pressure risk.
Not only that, I think it’s better to have a very, small narcotic sensation during the dive. A very small, very tiny sensation of narcosis. This acts as a reminder to me that says, “OK I am very deep and I need to be careful.” So, it’s a kind of alert. These are the reasons I don’t use pure heliox.
That’s understandable on deep tech dives because of High Pressure Nervous Syndrome (HPNS). Has HPNS been an issue for you?
Interestingly, during the descent, I often have the sensation of cold, above 200 m/656 ft, which could be the trimix, which is very near to heliox, in fact, with high levels of helium. Of course, the automatic diluent valve (ADV) is injecting the very cold diluent, and that could be the reason for my shakes. Then, for 20-30 seconds,when I reach 230-240 m/755-787 ft. I experience shaking, trembling, and some eyesight problems. However, when I continue my descent, the effects begin to disappear, and when I reach 260 to 280 m/850-920 ft, there is absolutely no effect. It’s over. It’s just 30 seconds or so at 230-240 meters.
Wow. It would seem that you are not affected much at all by HPNS. Again, it sounds like you have some unique physiology.
That’s exactly what I think.
Has anyone studied you to figure out how you can do what you do? Are you aware of any reason why this is?
It’s just practice and training, practice and training, that’s all. Year after year, dive after dive, I gradually began to have a low sensitivity to gas toxicity. I think that’s really the most important thing. The key is really the practice and the training.
I am not aware that divers can modify and or improve their gas tolerances through practice and training. I’m pretty sure that’s the case with nitrogen narcosis, despite what some have to say. Have you had any problems with carbon dioxide (CO2) buildup? Any CO2 problems?
This is an interesting question. There are two principal things about CO2. First of all, always choose the best performing soda lime for deep diving. You can use the cheap version of soda lime for shallow dives—it doesn’t matter. But for deep dives, below 200 m/656 ft, you should always choose the best performing product for that.
The other thing is during the decompression. During very long decompressions, like eight, nine, or ten hours of decompression, the human body produces a very small quantity of CO2. That’s the reason why I am able to do a 10-hour dive on the same rebreather with only 2.5 kilograms of soda lime inside. So, no, I have never had any problem with the toxicity of CO2. I don’t think I am very sensitive to it.
Have you ever had a caustic cocktail?
Yes, just once. I had just made a ventral rebreather. During my first dive, a connector on the counterlung came loose, and the rebreather slowly filled with water. At the end of the dive, at the surface in the basin, I put my head down to test breathing comfort. The caustic cocktail went into the mouthpiece and I breathed it in. I had a bad cough and a broken voice for several days.
Last question before we get on to your dive, what kind of support team do you use for deep dives? Do you use support divers? Where are they positioned?
I typically have a team of six divers, not more, positioned down to 80 m/262 ft. I have a diver wait at 80m/262 ft to be available for help if needed, and I descend from there by myself to make my dive.
So you are diving solo at depth. That seems to be the typical practice for über-deep dives with the exception of Richard Harris & Craig Challen and the Wet Mules. Do you ever think about doing these uber-deep dives with a team mate at depth vs doing the bottom portion by yourself with support divers high above you in the cave? Would it be safer?
In fact, it is safer to do this type of diving as part of a team. In most cases, I have a team around me. A dive director and support divers who intervene at different depths. In general, the maximum depth at which my team members intervene is the one where they can spend a lot of time waiting for me if I’m late. Usually, as I just mentioned in the 80m/262 ft zone. Having used more than 20 support divers on some occasions, I now limit my support team to a maximum of five or six divers. That makes it simpler for the dive director to manage. The support divers can make up to two assistance dives during the operation, the second dive being mainly during my final stops.
When the depth allows it, and other divers can accompany me, I prefer to dive in pairs. Like my explorations of Baume des Anges with Rick Stanton and John Volanthen or Durzon and Marnade with Pédro Balordi.
OK, let’s talk about the dive at Font Estramar. Let me first ask, how long you have been exploring the cave and the dives you’ve made there.
My first dive in this cave was in 2013. I did four successive operations in the same year in order to clear the record.
And the dives went as planned?
Yes. My first dive, the first exploration dive in this cave was to a maximum depth of 180 m/591 ft. My second dive was 248 m/813 ft, the third dive 262 m/859 ft, and fourth dive, just before the record, I spent at the same 262 m/860 ft depth with 40 m/130 ft of horizontal exploration, trying to find the way forward. I was unsuccessful, so I turned the dive and ascended.
I understand that you tested your rig in a hyperbaric chamber down to 320 meters/1050 ft of depth before the fourth dive in order to make sure everything worked well before going deeper.
Yes, I tested it in Switzerland with no problems.
Good. Everything checked out. So, you were able to find going passage on your fifth dive at Estramar and go deeper and ultimately ended up setting the record.
Exactly. So, after my fourth dive, I did an analysis of the videos, images, and everything I could remember about the environment. The result was I chose to think about continuing horizontally without going deeper. So, in planning the dive I prepared gases for a max depth of 280 m/919 ft. I used trimix 5.5/83 (5.5% oxygen, 83% helium, 11.5% nitrogen).
That’s a gas density of 10.76 g/l at max depth with the high oxygen and nitrogen levels, which is considerably above the recommended max of 6.2 g/l. Are you worried about your gas density or feel that it is OK for you?
As far as density is concerned, at the depths I go, it’s difficult to respect the recommendations, but as my JOKI rebreathers are very easy to breathe, compared with commercial equipment, breathing is very fluid and doesn’t bother me at the bottom. The most important thing is not to work hard and to use a diver propulsion vehicle (DPV). What’s more, I cycle regularly—at least 5,000 km a year—to get the basic training I need to control my breathing during a violent physical effort.
Back to the dive: you were able to find the way deeper into the cave?
Once I was on the bottom and into the terminus room of the cave, I looked all around me in order to find a pathway or passage. In fact, I didn’t find anything. But then I looked in the direction of the bottom and found a hole or well. That was the way deeper, and I spent another 30 minutes in the cave exploring.
You must have been excited! How far did you push it?
It was really a pure exploration at this depth. There was a passage, but it was a very, very small passage into this well. At around 270 m/886 ft, I found another room, a little bigger. At that point I had to make a decision. I knew I was very close to the world record, so I decided to try to push a little bit more to 286 m/938 ft, and then I turned the dive and began my ascent. I had not planned to go that deep, and in fact had a bit of stress.
I returned to the room at 262 m/860 ft, which was a bit tricky, and looked around but couldn’t find the line. I searched with my light and didn’t find it. I could feel my adrenaline and stress rise. Imagine losing the line at that depth.
OMG! That would definitely generate some stress!
One of my ties came completely undone, and the line had floated to the top of the room, where I couldn’t quite see it. The visibility is never good in Font Estamar. Fortunately, I did find the line after some tense minutes and continued my ascent.
Do you feel that you were at your physiological limit at that max depth? Or did you feel like you could go further in the future?
As I mentioned, I had some signs of HPNS when I hit 286 meters, but within a minute or so, there was nothing. All signs disappeared. I had a completely clear mind when I was trying to find the line. This is really proof to me that there is not a problem with the gas at this depth. Which means I can continue.
As you know, Richard Harris, aka Dr. Harry just completed a 230 meter test dive with a hydreliox mix (oxygen, hydrogen, helium) in order to lower the gas density and work of breathing and possibly ameliorate the HPNS. Have you given thought to using hydrogen?
Of course, I have talked about hydrogen with Jean-Pierre Imbert and Bernard Gardet, who was the scientific director at COMEX. But there is no problem for me right now. Using a rich trimix is not a problem. I only have the slightest tremors which then go away. So no, I don’t think there is a reason to change anything. I think I can continue to 300 m/984 ft with helium.
Have you had any close calls on your dives?
Yes, a Bonex scooter that I was towing between my legs imploded at the bottom of St Sauveur. It had suffered some shocks on previous dives in very narrow cavities. The explosion tore a hole around 3 cm in my drysuit—it was no longer a drysuit, but a wetsuit. It was completely filled with water during my seven hours of decompression.
OMG! How cold was the water?
13°C for seven hours! Yeah, it’s a little bit cold.
Were you using a habitat, deco habitat?
No, no I wasn’t.
That must have been grueling.
Have you ever gotten bent? Decompression sickness?
No, no, no, nothing. Again, I think it’s my physiology, and the rigor and specific training and practice, being careful every time for everything I do.
What are your plans for the future Xavier?
This Fall, I would like to continue my explorations of the Gouls of Tourne and try to find the junction between Goul du Pont and Goul de la Tannerie. And I plan to continue my explorations at Port Miou, which is not deep, and also the Source du Marnade and the Durzon.
I am guessing that you have specific goals and objectives for each.
Yes, many goals, and many objectives, in fact. To simplify, the object is to map and explore the different sites, continue to find new galleries, and in the case of Goul du Pont, find out if there is a connection.
So many caves, so little time! Will you also be returning to Font Estramar. Do you plan to go deeper there?
It’s not a principal target. I continue to think about it and try to make the best decision about this specific site. But it’s not the first target. I want to continue the exploration of the other sites first, but I do think it’s possible to reach 300 meters at Estramar.
Good luck to you Xavier! We’ll be watching. Thank you!
YouTube: World Record Cave Dive – 282.6 m (927 feet) – Nuno Gomes (1996)
Facebook: Xavier Méniscus-New World Record
therebreathersite.nl : Le Joky mCCR
InDEPTH: Omne Trium Perfectum
Seacraft DPV: AMBASSADORS XAVIER MÉNISCUS
YouTube: Cave Diving in France legendary Font Estramar by Europe Cave Diving
Michael Menduno/M2 is InDepth’s editor-in-chief and an award-winning journalist and technologist who has written about diving and diving technology for more than 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, and he produced the first tek.Conferences and Rebreather Forums 1.0 & 2.0. In addition to InDEPTH, Menduno serves as an editor/reporter for DAN Europe’s Alert Diver magazine, a contributing editor for X-Ray mag, and writes for DeeperBlue.com. He is on the board of the Historical Diving Society (USA), and a member of the Rebreather Training Council.