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By Michael Menduno
Header photo by Barry McGill
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 today from those in the 1990s when technical diving was just getting started.
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 130 ft/40 m 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 min of bottom time to depths of 260 ft/79 m to represent a reasonably safe envelope for mixed gas tech dives, hence Dean’s comment 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 as “exceptional,” requiring special methods and work.
Deep Shipwreck Dives in The 1990s
The first table (below) highlights the ten deepest tech wreck dives from 1989-1999, including the location, depth, dive profile, technology used and the technical divers who first dived the wreck in question. The majority of these dives was reported at the time in my magazine aquaCORPS Journal.
The deepest tech shipwreck dive at the time was on the Edmund Fitzgerald lying in 530 feet (162 meters) of fresh water in Lake Superior the equivalent of 514 ft/157 m of sea water. The shallowest was the RMS Lusitania near Kinsale, Ireland at 310 ft/95 msw.
Note that the depths listed in both tables should be considered as relative metrics. In most cases, the depth indicates the depth at the bottom of the wreck. In some cases, divers actually dived to the bottom. In other cases, the depth indicates the depth that divers actually reached. In other words, the depth numbers are a bit fuzzy.
There are several observations to be made. First, all of these dives but one, were conducted on open circuit scuba. At the time literally, only a handful of technical divers 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 production rebreather, wouldn’t be released until 1997. In the case of the RMS Niagara (392 ft/120 m), Tim Cashman and Dave Apperly were using rebreathers made by Apperly. Though mixed gas technology was a necessary precursor, rebreather usage would not hit its stride for another decade.
Two of the dives shown on the chart, the SMS Frankfurt (420 f/129 m) dived in 1994, and the Ostfriesland (380 f/117 m) dived in 1990, were conducted by wreck diving pioneers Ken Clayton and Gary Gentile on heliox. Clayton also dived an experimental Neox mix (02 and Ne) for their last dive on Ostfriesland to 340 f/104 m with 20 min BT.
In 1989, the Clayton, Gentile and their team also conducted a deep air dive, with air decompression—can you imagine??—on the USS Washington (290 ft/89 m), which would have been #11 in the 1990s table. Ironically, though cave divers quickly embraced “special mix” technology, the majority of dedicated U.S. Northeast wreck divers were slow to adopt mix technology to replace their deep air diving though they did add 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 on the list in 1995, first on the Fitzgerald in 1995 with Mike “Zee” Zlatopolsky, and then on the Atlanta with Aussie pioneer Kevin Denlay.
Though the rumor was that Tysall and Zee had made a “sneak dive” on the Fitzgerald which was a grave site, the two were able to obtain a permit, but it did not allow them to tie into the wreck. They ended up using the drop camera umbilical as a downline, and left a plaque on the “Fitz” to commemorate the sailors that had been lost. However, they were only able to make a single dive due to the weather.
Clayton, Gentile and their teammates accounted for three of the ten deepest wrecks while Gentile was involved with four of 10, and Deans and his team accounted for two dives on the list. Note also that British tekkie Polly Tapson, one of the first female tech expedition leaders, and her team Starfish Enterprise captured the imagination of the community at the time with the preparations and their successful dives on the “Lucy” 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 Ingmar 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 footnote.
In terms of depth, the average depth of these 1990s wrecks is 389 ft/122 m average bottom time: 16.7 min, and average run time: 192 min or just more than three hours.
The Deepest Shipwreck Dives Today
The second table shows the 30 deepest technical shipwreck dives as of this year identifying the first tech teams to dive on the wrecks. Note that only the eight deepest shipwreck dives from the 1990s made it on the list. The deepest tech shipwreck dive, was on the Milano lying at a depth of 774 fresh water (236 mfw) in Lake Maggiore, Italy, (the equivalent of 751 fsw/176 msw), conducted by Pim van der Horst, Mario Marconi, and Alessandro Scuotto in 2008, with the help of diving pioneer Nuno Gomes who was a consultant and witnessed the dive.
The 30th deepest wreck dive is now the SMS Ostfriesland (380 ft/116 m), which was just slightly shallower than the average depth of the Ten Deepest Shipwrecks from 1990. The deepest wreck dive in the 1990s, that being the SS Edmund Fitzgerald, aka ‘The Fitz,” laying at 529 ffw/162 mfw, is now #11 when viewed from today. That is to say that the top ten deepest shipwreck dives were all conducted after 2000.
Note also there is one high altitude shipwreck dive on the list being the SS Tahoe at 471 feet of fresh water/144 m, the equivalent of 457 ft/140 m of seawater, which lies in Lake Tahoe at an altitude of 6224 ft/1897m. 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 in 1992-1996 at Boesmansgat sinkhole that lies at an altitude of 5000 ft/1500m in South Africa were possibly more extreme.
Also interesting, 9 of the 13 wreck dives in the deepest 10 today (there were multiple shipwrecks at the same depth) were conducted on rebreathers vs. four on open-circuit scuba. All but one of the 10 deepest shipwreck dives in the 90s were conducted on open circuit. All the 30 deepest dives but two, were made using trimix as a back gas or diluent, the exception was the Frankfurt and Ostfriesland first dived by Clayton and Gentile and team as noted above.
Closed-circuit technology is largely responsible for the deeper depths and longer dives we see today. The average depth of the ten deepest shipwreck dives listed in chart two is 576 ft/176m, or 178 ft/75 m deeper than the ten deepest shipwreck dives from the 1990s. Average bottom time for the deepest 10 today was 15 minutes compared to 16.7 min for the 1990s wrecks, however average run time was 316 minutes or more than five hours, compared to a little over three hours in the 1990s.
The amazingly prolific Italian diver Massimo Domenico Bondone and his team accounted for six of the dives in the 20 of the 30 deepest shipwrecks! Wow! He is followed by Irish tekkie and photographer Barry McGill, his colleague Stewie Andrews, and their various teams who were responsible for four of the deepest dives shown on the table. 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 three of the dives as were Ken Clayton and Gary Gentile (from the 1990s). Tysall
Was responsible for two dives on the list, the Fitzgerald and the Atlanta.
Have we bottomed out our depth capability as self-contained divers? If history is any judge likely not. My long-held belief is that self-contained atmospheric diving systems aka Exosuits or hard suits, such as those pioneered 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 a while before divers will have access to $10,000 swimmable Exosuit.
Even so, it will be interesting to see what the list of the 10 deepest tech shipwrecks dives will look like in 2029.
Editor’s Note: This post evolved based on input from our readers. Here were the two earlier versions:
A printed version of this article was published in the “Journal of Diving History, Third Quarter 2019, Vol 27 Number 100.
Table 1: 1990s
Deepest 10 (1989-1999): 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 not a “sneak” dive. The two obtained permits to dive the wreck but they didn’t allow the divers to tie in.
** 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.
Table 2: 30th Deepest
Deepest 10 (1990-2018): Average depth: 576 fsw/1176 msw, Avg. Bottom Time: 15min, Avg. Run Time: 374 min
*The Jolanda sits vertically from 70-150 msw. According to M. Ellyat, Gregory ‘Banan’ Dominik found and dived the deep bit of the Yolanda in Sharm 3 years before Mark Andrews and Leigh Cunningham.
** According to M. Ellyat When he found the Victoria in 2004 it was almost intact in 156m. Subsequent dynamite fishing has blown the inner decking down to the seabed making it appear 144m.
***Rizia Ortolani set the then Deep Wreck Female record on this dive.
**** 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.
****** 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. Subsequent dives with BT: 15 min were made with Trimix 14/54. The team deco’d in a bell. Greek commercial diver Kostas Thoctarides followed Cousteau in 1995 making a solo 20-min dive, and returned in 2001 with a submersible.
********Clayton dived Neox mix (O2 and Ne) for their last dive on Ostfriesland to 340 f/104 m with 20 min BT.
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 OZTEKMedia Excellence Award in 2011, the EUROTek Lifetime Achievement Award in 2012 and the TEKDive USA Media Award in 2018.
Citizen Science to The Rescue: Getting to the Bottom of Lake Tomarata
Lake Tomarata and the surrounding wetlands near Auckland, New Zealand were mistakenly believed to be low-value habitat with limited–to–no biodiversity. That’s until water quality scientist Ebi Hussain and his posse of citizen scientists took up the case and started collaborating with local partners. Here’s what a team of dedicated volunteers can do.
by Ebrahim (Ebi) Hussain
Header image: Louise Greenshields installing continuous pH and dissolved oxygen sensors. Photo by Ebi Hussain
Lake Tomarata in New Zealand’s Auckland region, is surrounded by an extensive wetland—the only one of its kind in this region. Its ecological significance and rich native biodiversity, including several threatened and endangered species, make the lake and wetland complex unique and deserving of protection. It is dangerously significant that only ten percent of New Zealand’s wetlands still exist.
A very small subset of these wetlands are considered as lacustrine wetlands, making this ecosystem critically endangered; only one percent of this wetland’s original extent remains. The lake itself is equally unique and is the only example of a peat lake system in the Auckland region. The fact that these two very rare ecosystems exist together in one place makes this site extremely special and has set the stage for our most comprehensive project to date.
Both the lake and wetland have been independently studied before, but there has been no ecosystem scale assessment that examines both systems as one interconnected environment. The wetland values are well-described in published literature. However, the ongoing pressures and impacts from the surrounding catchment are not fully understood. The lake has been monitored over time, and the general consensus is that there is limited to no biodiversity values present and the water quality is deteriorating .
Our visits to the wetland and dives in the lake alluded to something more than the degraded systems described. Instead, we uncovered a misunderstood environment with complexities that led to the false assumption that the lake had low ecological value. This highlights the value of citizen science and in particular, divers that are able to regularly document areas that most people don’t frequent.
We wanted to legitimize our findings and debunk the false portrayal of this unique environment. To do this, we wanted to create an open access integrated ecosystem management tool that could be used for collaborative monitoring and restoration. This tool would need to be based on accurate ecosystem scale assessments and integrated into a single geospatial platform where all data could be viewed and interpreted. To create this tool, we needed to map the entire environment as one ecosystem, establish an in-lake biodiversity baseline and current state assessment for both systems, integrate all the data, and develop monitoring techniques that would inform management plans.
This seemed completely unachievable for a group of volunteers, but we did not let the monumental task intimidate us. We drew up a plan, put together a team, and pushed on one step at a time.
Draw Me A Map
The first step in understanding an ecosystem is to map the environment and create a spatial platform to guide in-situ surveys and integrate multidisciplinary data. This project was the first time we mapped aquatic, terrestrial, and transitional environments to create a single ecosystem model.
The challenge with this type of mapping was that we needed to work in three dimensions because the surface and subsurface environments are interlinked. The best way to do this was to use various survey techniques and data inputs for each environment to create an integrated, three-dimensional model of the entire ecosystem.
To map the lake, we used existing hydroacoustic data collected using a variety of methods including sonar, depth sounders, and pressure transducers to create a bathymetric map of the lakebed. We used divers to ground-truth (i.e., check the accuracy of) the bathymetry, and map the shallow transitional areas between the lake edge and the wetland. The result was a high-resolution map of the lakebed and general lakebed characteristics.
We mapped the wetland using drone imagery and existing data inputs. We flew a drone along a pre-programmed geo-referenced grid that spanned the entire sub-catchment to obtain high resolution imagery. This imagery, coupled with LiDAR data, was used to create a three-dimensional point cloud, ortho mosaic, and digital elevation model of the entire sub-catchment.
We combined the surface and subsurface mapping to create a single three-dimensional model of the entire ecosystem. This gave us the ability to visualize both systems as an integrated environment and extract detailed spatial and environmental information. This model would also be used to display and integrate all the survey data. To frame this data into the context of the wider landscape, we overlaid the catchment land use split, overland flow paths, soil types, and ecosystem classification. This allowed for a greater diagnostic power when assessing the potential impacts of changes in the wider catchment.
Assessing Lake Biodiversity
The biggest knowledge gap we faced was in-lake biodiversity. There have been several reports discussing the general health of the lake and discrete ecological surveys, but no conclusive lake-wide assessments. One of the conclusions drawn by a majority of the published literature was that the lake is completely devoid of plants and is overrun by pest fish species.
We used the bathymetry to design a lake-wide survey aimed at assessing habitat quality, macrophytes, key stone species, and benthic flora and fauna. The first survey was to map out specific habitat types throughout the lake; these areas were then plotted on the three-dimensional model. We used the habitat assessments to guide the other biodiversity surveys, since they gave us an idea of where various species may occur.
During the biodiversity surveys, we made some ground-breaking discoveries. Despite the lake being classified as non-vegetated, we have mapped nearly 1 km/0.62 miles of native macrophyte beds along the southern and western ends of the lake. We also found freshwater mussel beds on the eastern side of the lake, which was an amazing discovery, as no one knew these endangered species existed here. Recently, we were lucky enough to find the first juvenile freshwater mussels ever recorded in an Auckland lake.
So far, our findings indicate that this lake is far from a barren waterbody. There are signs of natural regeneration and established populations of endangered species. It is critical that we get this message out and raise the profile of this lake: the more we know about a place, the more we value its protection.
Establishing a Baseline
A baseline state is essential to track changes over time. We wanted to take an integrated ecosystem approach to the baseline assessment rather than focusing on tracking single metrics and using them as a proxy for wider environmental health.
The first step was to use the three-dimensional model we created to define the current extent of both the wetland and lake environments. Tracking changes in extent over time provides information on wetland succession/recession, water level, lake infilling, and habitat change. We used the high-resolution drone imagery to delineate discrete vegetation types across the wetland, and we aim to calculate vegetation biomass in the future. This will allow us to track changes in vegetation assemblages in response to eutrophication, sedimentation, and climate change.
The in-lake biodiversity assessments were used to create a baseline for in-lake health. Ecological response metrics like macrophyte extent, mussel density, substrate/habitat change, and species diversity will be used as a biological sentinel network that integrates the effects of multiple impacts across the ecosystem.
Changes in water quality are pivotal to both the lake and wetland, so it is crucial that we fully understand the current state. To understand the diurnal and seasonal variation in water quality, we installed continuous water quality sensors (temperature, pH, dissolved oxygen, and light) at every meter through the water column; these sensors will log measurements every 15 minutes for a year. This data, coupled with the monthly water quality samples and climate data from the Auckland Council, will be used to create an in-lake process-based model that can be used to understand and predict lake dynamics.
We will also integrate additional data such as bird counts, pest fish surveys, and hydrological studies collected from other agencies into our assessment. This information, along with other geospatial data, can continually be added to the platform as they become available.
Tracking all these parameters creates an early warning system able to detect subtle changes in ecosystem health. This integrated response-based approach is more sensitive than traditional monitoring methods. The in-lake, process-based modelling will continue to be calibrated as we collect more data, which will eventually allow for accurate scenario testing. The end goal is to be able to detect changes early enough that we can test virtual restoration/management scenarios and implement the most effective solution before significant degradation occurs.
Management & monitoring
The key to successful ecosystem scale management is collaboration. We created an open access platform for everyone with a vested interest in this area, not only so they could use the model, but so they could also contribute their own data. We established the baseline ecosystem state—which can be referenced in all future studies—as well as the monitoring tools required to track environmental changes. The last step will be to introduce people to our work and set up collaborative working groups focused on Lake Tomarata.
Currently, we are partnered with the Auckland Council, which has regulatory authority over the area. The Council and Aotearoa Lakes have a joint monitoring and data-sharing agreement which allows both parties to benefit from pooled resources, expertise, and data. We are working with the local communities and tribes from the area to raise the profile of this ecosystem and create an interest that will hopefully lead to proactive lobbying and restoration efforts.
Our integrated ecosystem monitoring design, spatial representation of multidisciplinary data, and ability to scenario-test management options creates a publicly accessible platform for informed collaborative ecosystem monitoring and management.
What makes this effort so special is that it was all done by dedicated volunteers. This project proves that citizen science can stand up to the rigor of commercial standards and in some cases even surpass it. I hope this article will inspire you to take action despite how Herculean the task may appear to be. There is nothing more powerful than a collective of like-minded people applying themselves to a single cause.
Please visit our website Aotearoa Lakes: Citizen Science for Our Lakes for more information on our projects. Note that “Aotearoa” is the Maori (the indigenous people of NZ) name for New Zealand, literally meaning, “land of the long white cloud.”
Check out their 3D model of Lake Tomarata: Aotearoa Lakes Eco-Maps. To get to the Lake Tomarata model, click on the website maps link (above). A banner pops up along the bottom of the screen with pictures of various lakes side by side. Click on the “Tomarata Lake” site which is the 3rd box from the left on the bottom banner.
Facebook page: Aotearoa Lakes: Citizen Science For Our Lakes
Home of Project Baseline
Ebrahim (Ebi) Hussain is a water quality scientist who grew up in South Africa. As far back as he can remember, he has always wanted to scuba dive and explore the underwater world. He began diving when he was 12 years old and he has never looked back. Diving opened up a new world for him and he quickly developed a passion for aquatic ecosystems and how they work. The complexity of all the abiotic and biotic interactions fascinates him and has inspired Ebi to pursue a career in this field.
He studied aquatic ecotoxicology and zoology at university, and it was clear that Ebi wanted to spend his life studying these subsurface ecosystems and the anthropogenic stressors that impact them. After traveling to New Zealand, Ebi decided to move to this amazing country. The natural beauty drew him in, and even though there were signs of environmental degradation, there was still hope. Ebi founded Aotearoa Lakes with the goal of contributing to, preserving, and enhancing this natural beauty as well as encouraging others to get involved in actively monitoring their natural surroundings.
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