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Make Time Fly During Decompression

How do you deco? Find out how divers are spending those long hangs.



By Amanda White

As a new diver, I’ve always wondered what tech divers do underwater during those long decompressions. It blew my mind when I would hear about 30-minute bottom times and six-plus hours of decompression. Some of the time there is nothing around, and the divers are just hanging there in blue water for hours!

Not all of us spend hours decompressing on dives. But, if you’re curious and mystified like me, or are looking for a new way to pass the time during those long hangs, here are some ideas from deco divers that I polled.

Are You Down for a Game of…

Times flies when you’re having fun, right? And one classic way to pass the time is games. Some divers are playing games like, rock-paper-scissors, tic-tac-toe, and hangman. With wetnotes, divers can even play things like Sudoku while 30 meters below the surface.

Submitted by Dan Nott.

Some divers even take things a step further with mini travel checkers and chess boards. Or they pass the time by taking photos of themselves and their dive buddies.

Photo by Brian Richardson.

She Swims with the Fishes

Some people are lucky and their decos can take place along reef walls or other environments teeming with life to see and explore. They may even get a visitor while hanging in the blue water.

Tech diver and explorer Louise Greenshields is loving her deco. “We’re totally spoilt over here in New Zealand at the Poor Knights Islands. We spend our deco searching out critters on the amazing reef walls that are here to enjoy 😉 #sorrynotsorry ”

Dr. Sonia Rowley is a research associate at the University of Hawaii at Manoa who is studying deep reefs. She doesn’t complain about her deco. “I love every minute of it and I have a hard time mustering up the willingness to get out of the water,” Rowley explained to me. “Case in point: my recent research trip to Balls Pyramid off Lord Howe Island where I had the constant companionship of a lot of Galapagos sharks. They were extremely playful and every time I swung around there was a ‘sea of noses’ following my fins. It was very funny.”

Dr. Sonia Rowley taking a photo during one of her decos. Photo by Richard Pyle.

Killing Two Birds with One Stone

You can also make your time count by helping researchers gather data or completing more of your dive objectives during your deco along a reef or in a cave.

Dr. Rowley does this with her current research. “With regard to long decos, that depends on the dive site. Generally, I continue to work up the reefs and select study sites specific to this so more data and research can be achieved. If, however, it is bluewater deco then I play with the pelagics and plan my research, data analyses, gases for the following day, and take the opportunity to film the environment.”

Beto Nava and his team discovered the oldest human remains found in North America inside of the Hoyo Negro cave system in Mexico. He also conducts working hangs. “During the Hoyo Negro project we work on different tasks during the shallow part of our decompression, mostly from 50 ft/15 m and up. This helps us to increase our productivity by also doubling the time we work underwater, and it reduces the mental stress of a long decompression. We collect survey data for cartographic maps, like for example, line re-surveying, side walls measurements, and many others. Sometimes we capture images for 3-D models of sections of the shallow tunnels.”

Photo submitted by Beto Nava.

Time Passes with Your Friends, Harry, Ron, and Hermione

Kirill Egorov, a tech and cave instructor and avid underwater explorer, has mastered his decompression entertainment. “I use a waterproofed iPod shuffle to listen to audiobooks (Harry Potter; The Long Ships, and The Hollow Hills). I also read paperback books (Alamo and  Day of Infamy). Older books are apparently printed on better quality paper; “I managed to read them over multiple dives. The newer ones barely survive a single dive.”

He’s not the only diver to read books underwater. GUE President Jarrod Jablonski has also taken the time to read during deco. “I would read paperback books and freeze them between dives, which seemed to hold them together longer. However, these often came apart and usually within the last few chapters. I missed many endings to various books as a result.”

Submitted by John Kieren and taken by Marc Adolf.

Get Your Groove on at 9 Meters

There are also companies out there that make devices you can take with you to listen to your favorite tunes while underwater… how well they work is another story.

Jablonski is an avid explorer and has set world records in cave diving, so he’s spent his fair share of time in decompression.“I have used a variety of strategies and built my first underwater sound system in 1990. That was built with an old cassette player and custom light housing paired with normal headphones that I wrapped in balloons and dipped in a latex compound to seal. Sound quality was not great but it was a diversion. Later I would use proper, underwater headphones and a MP3 player.”

But even if you don’t have an underwater MP3 player, you can still enjoy some music. Mary Adams, a deco diver, passes the time by singing songs in her head. “I sing 80s rock songs,” she said. They’re 3 minutes long, and I also look for sharks and mantas.”

It may not be the same as belting it out in the shower, but it can definitely pass the time.


Namaste in the Water

Something as basic as just pondering your thoughts or taking the time to meditate can also be a good use of your decompression. Who knows, maybe you will solve one of the world’s pressing problems during deco.

Dive instructor Rich Walker uses this time to relax in his “nothing box.” “When I get to 6 m/20 ft and settle into my decompression, I go to my “nothing box,” open it, and immerse myself in the nothingness. I can stay there for hours. It’s my most powerful ally on a long decompression because time just slips away, much faster than watching the clock, reading a book, or reviewing the dive. Everyone should cultivate their nothing box.”


Watching Blue Planet While in Big Blue

John Kendall, a dive instructor and photogrammetry guru, has spent his fair share of time in deco. “I have a (ridiculously expensive) waterproof android tablet that I use to watch movies during long cave deco. For open ocean it’s a bit harder, so then it’s normally a matter of just trying to both stay neutrally buoyant and awake.”

I wonder if there is a record for the greatest depth someone has watched a movie at? One or two movies and your deco is over.

Gershwin the Bear Explorer with Kendall’s tablet before a dive. Photo submitted by John Kendall.

It’s like a Clubhouse for Divers

Some technical divers are lucky and they get to spend their long decompressions inside of a decompression bell like those used by commercial divers.

Richie Kohler is one of the explorers on several of the recent expeditions to the Britannic that was lucky enough to have a commercial diving bell available to make his long deco tolerable.

Photo submitted by Richard Kohler. Photo by Michael C. Barnette.

“Our approach to combat boredom on our five to eight hour in-water decompression obligations has certainly changed over the past 11 years since my first Britannic expedition. In 2015 and 2016, Britannic operations had the opportunity to use the Russian Geographical Society Vessel, U-Boat Navigator, which had a diving bell for our operations. The clear acrylic dome provided a space where two fully geared divers could stand and be out of the water from the chest up. The bell had a camera and microphone for real-time conversation and observation of the dive team. The bell also had a hot water system that we used to warm our hands and heads during the long hangs. We could play music through the bell and there were various snacks inside the dry area (Swedish fish was a big hit) that we had not been able to enjoy before.

The team took turns standing out of the water, feeling the tug of gravity, easing jaw aches by leaving the loop out, and taking an air break in the bell. And the rotation of four divers taking turns in the bell also helped wittlle away the hours. We still had an in-water support diver watching the dive team and we practiced and prepared for a possible unconscious diver scenario where we would get the stricken diver in to the bell and out of the water quickly. The bell was a cozy little shack and I think it has ruined me for any future long decompression obligations.”

Photo submitted by Richard Kohler.

Others, particularly cave divers, are convinced that decompression habitats are the ticket. Some of these even have WiFi, which brings a whole new level to updating your Facebook status.

Andy Pitkin, one of the divers on the KUR Twin Dees project, is one of the few divers to have had the luxury of a WiFi habitat. “We try to be as comfortable as possible, and hopefully that involves use of a habitat. We have taken this to quite a level with watching movies on an iPad and even rigging up a wireless access point so we can get internet access down there.”

Twin Dees habichat December 8th 2018 from Andrew Pitkin on Vimeo.

All of these divers are part of a team that is also keeping track of their teammates, the time, the depth, the environment, their gas, and any other factors that could influence their safety while at the same time trying to entertain themselves.

If you do something fun or intriguing during your deco stops that isn’t listed here, let us know at indepth@gue.com.

Header Image by Julian Mühlenhaus.

Amanda White is the editor for InDepth. Her main passion in life is protecting the environment. Whether that means working to minimize her own footprint or working on a broader scale to protect wildlife, the oceans, and other bodies of water. She received her GUE Recreational Level 1 certificate in November 2016 and is ecstatic to begin her scuba diving journey. Amanda was a volunteer for Project Baseline for over a year as the communications lead during Baseline Explorer missions. Now she manages communication between Project Baseline and the public and works as the content and marketing manager for GUE. Amanda holds a Bachelor’s degree in Journalism, with an emphasis in Strategic Communications from the University of Nevada, Reno.


Brits Brew Beer Booty

What do you get when you combine British divers’ proclivity for shipwreck exploration with their strong affinity for beer? A tasty treasure hunt on the “Wallachia” that resulted in swilling 126-year old reconstituted British beer. GUE Scotland’s detective chief inspector Andy Pilley recounts the tale.




by Andy Pilley
Images courtesy of
A. Pilley

Header Image: GUE Scotland’s brewmeisters enjoying their brew (L to R) Top: Owen Flowers, Andy Pilley, Wayne Heelbeck. Middle: Steve Symington, A. Pilley, O. Flowers, Bottom: W. Heelbeck, Sergej Maciuk, S. Symington

“Give my people plenty of beer, good beer, and cheap beer, and you will have no revolution among them.”

Queen Victoria

I never thought when I started diving 10 years ago, that one day I would be able to sit down for a pint of beer with the team from GUE Scotland recreated from a brew that has been hidden under the waves for 126 years. Let me explain.

The Wallachia was a single screw cargo steamer that was owned by William Burrell & Son of Glasgow, and employed on regular trips between Glasgow and the West Indies. On 29th September, 1895 she left Queen’s Dock, Glasgow at 10am bound for Trinidad and Demerara. On board was a valuable general cargo including whisky, gin, beer, acids, glassware, and earthenware plus building materials and footwear. By 1pm that afternoon she had settled on the seabed of the Clyde Estuary after colliding with another ship in a fog bank, she was forgotten until 1977 when a local sub-aqua club rediscovered the wreck site.

The wreck of the Wallachia lies on an even keel in approximately 34 metres of water on a sandy seabed. The wreck itself is largely intact and has six holds in total, three forward and three aft. In the rearmost hold there are thousands of bottles of beer, some still inscribed with the name of the maker, McEwans of Glasgow. This is where myself and the team from GUE Scotland enter the story.

The Wreck of the Wallachia 

The Wallachia is one of the more accessible sites on the west coast of Scotland, where we carry out most of our diving. Depending on weather and tidal conditions, visibility on the wreck can be +10m/33 ft on a very good day or less than 2m/6 ft if there has been a lot of rain due to the amount of particulate in the water. Other elements to consider are the tide as this can vary in its intensity, as well as surrounding boat traffic. The wreck lies in close proximity to a ferry route and care must be taken not to dive when the ferry is closeby. However despite the challenges, the wreck is very rewarding and offers a diver plenty of places to explore and items to look at. 

The main point of interest for most has been the rearmost hold, where the bottles of whisky and beer were stored. The majority of the whisky was removed in the 1980’s however a few bottles can be found on occasion, depending where you look. What remains are thousands of bottles of beer, still with the corks and contents intact. Over the course of 2018 & 2019, the team at GUE Scotland dived on the wreck and recovered a number of bottles from the hold. 

After a chance discussion with a friend at dinner one night, I was given contact details for a company called Brewlab, which is based in Sunderland in the north east of England. Brewlab specialise in the provision of specialist brewing training, as well as laboratory services such as quality assurance, product development, chemical/microbiology testing as well as long term research options. I made contact with Keith Thomas, the Director of Brewlab, to discuss whether he would be interested in analysing the beer and investigating whether it could be recreated. Needless to say the proposal piqued his interest and arrangements were made for the bottles to be shipped to his lab.

Unbeknownst to me, the recovery of historical beers is rare, due to various sources of degradation/contamination which can affect any residual microbial cells and chemical components left in the beer that were used as part of the brewing process. So these samples are a valuable source of information on past brewing and microbiology. Over the course of 2019/2020, Keith and I kept in regular contact over the progress of the investigations and the full analysis of the beer has recently been published.

A Brewing Interest

Between 1850 and 1950, the application of scientific principles to brewing was becoming increasingly prevalent and microbiology was playing an increasingly important role. A pertinent issue in brewing microbiology around 1900 was the application of pure Saccharomyces yeast cultures developed by Hansen at the Carlsberg laboratory in 1888. These were readily adopted by continental breweries as providing more controlled production and purer beers. Application to UK brewing was, however, less positively received, in part because of the belief that British beers possessed particular flavours arising from mixed yeast cultures and, specifically, the involvement of Brettanomyces species. This was especially believed to be essential for the character of ‘stock’ ales which were matured for extended periods.

While a number of breweries did try pure culture yeasts, UK brewing was resistant to change and, with the intervention of World War I, retained its indigenous yeast cultures. Since the 1940’s a more biotechnological approach to fermentation demonstrated the value of pure culture and was progressively applied to the larger breweries developing at that time. 

During the formative period of brewery microbiology after Pasteur, brewing yeast were identified as Saccharomyces species based on morphological features of shape, filamentous propensity and spore characteristics. Non brewing, ‘wild’ yeast was recognised and termed ‘Torula’ if non-sporulating. Of these Brettanomyces strains were identified as contributing important character to stock ales. It is also clear from brewing texts that bacteria were recognised as spoilage organisms in beer, as had been initially demonstrated by Pasteur in 1863. These species were mostly categorised as bacilli and typically portrayed as rods and associated with sarcina sickness – generally producing sourness. Some studies, nevertheless, identified lactic acid bacteria as indigenous components of standard beers.

Contemporary breweries are increasingly interested in using novel microbiology, either unconventional yeast strains or mixes of species and strains for sour and natural products. Identifying the specific strains and species of yeast and bacteria present in Victorian and Edwardian beers is directly relevant to this and has particular value if cultures of authentic microorganisms can be retrieved. Reports of retrieved historic brewery microbiology are limited but hold interesting promise for identifying novel microorganisms.

The specific parameters of the analysis are contained in a published research paper, Preliminary microbiological and chemical analysis of two historical stock ales from Victorian and Edwardian brewing.”

As I mentioned, the primary objective of the analysis was to confirm whether detail could be provided on the original brewing ingredients and the fermentation microbiology. The analysis confirmed the use of Brettanomyces/Dekkera bruxellensis and Debaryomyces hansenii, which are brewing and fermentation yeasts respectively. The presence of Debaryomyces is interesting as this genus has not been noted as a historic feature of historic brewing, but has been identified in spontaneous fermentations, for example in Belgian lambic beers. Although the strain was reported to the brewing industry in 1906, it has not featured as a major contributor to beer fermentations since.

The analysis has also provided relevant information of the beer character and has confirmed that the beer recovered from the Wallachia was a stout, close to style expectations of the time and had an alcohol content of c. 7.5%. The colour gravity was high, resulting in a much darker beer however a much lower level of bitterness. Again this was typical style of the time and differs from other modern stouts.

More interestingly is the presence of various types of bacteria, which will likely have been picked up during the brewing process. The table below lists these for reference. Needless to say, historic brewing was not a sterile process in comparison to modern methods!

Bacillus licheniformisPlant and soil bacterium
Finegoldia magnaCommensal skin bacterium
Fusobacterium sp.Possible pathogenic bacterium
Kocuria roseaPossible urinary tract pathogen
Mogibacterium pumilumPossible oral cavity bacterium
Shigella sonneiEnteric pathogen
Staphylococcus epidermidisCommensal skin bacterium
Stenotrophomonas maltophiliaSoil bacterium
Varibaculum cambriensePossible pathogenic bacterium

Table 1: The bacteria found in the Wallachia beer bottles

Due to the relatively stable conditions on the wreck, being in near darkness and at a relatively cold temperature (between 6º–14ºC/43º-57ºF depending on the time of year), the live yeast structures within the beer were protected from sources of stress and allowed them to survive over the past 126 years. Luckily, Keith was able to extract these samples and begin to recultivate the yeast, specifically the Debaryomyces, with the hope of being able to rebrew the beer.

Cheers Mates

Just before Christmas, I finally received word from Keith that he had completed a trial brew and seven bottles of the brew were on their way to me. A few excitement laden days later and a nondescript box arrived at my office with the beer inside. I called the guys on our Facebook group chat to show them the case and got each bottle packaged up and sent out to them. 

A few days later, once everyone had received their sample we got together again to try the samples. There was an air of excitement after the two years it had taken us to get to this point, the most anticipated pint ever! I’m no expert in the flavour profiles of beer so you will have to forgive me for my relatively basic analysis. In summary, I got flavours of coffee and chocolate and there was a relatively low level of carbonation, which made it very drinkable. The rest of the team got similar flavours, the only complaint being there wasn’t more to try!

There will of course be slight differences in flavour since we don’t normally add the bacteria listed above as ingredients. However, the recipe we have is as close as we can make it to the original stock version.

The next steps for the project are to carry out further investigation on the characteristics of the Debaryomyces yeast strain in order to determine their suitability for fermentation and potential use in future brewing production. We are making approaches to various commercial breweries in order to discuss future commercialisation of the recipe and produce the brew on large scale. With the story behind the original recipe, we’re hopeful that the provenance would be a key selling point to consumers. It is my hope that the recovery of these samples will open up new possibilities for different types of beers to be developed, and offer something different for beer enthusiasts to try.

I have also found out that there are other types of beer to be found on the wreck, specifically an IPA style. Once we’re allowed to begin diving again, I am hoping to return to the Wallachia and recover some of these bottles so we can carry out the same analysis and keep the project moving forward.

In the mean-time, cheers!

Additional Resources:

The Brewlab Podcast, Episode 2 (March 30, 2021): Lost Beers Recreated from Shipwreck Bottles

GUE Scotland vlog -Episode 1

Andy Pilley is a Chartered Surveyor, team member of GUE Scotland, passionate wreck & cave diver and Ghost Fishing UK team diver. Andy started diving with the Scottish Sub-Aqua club in 2011 and began diving with GUE in 2018. Andy dives on the east and west coasts of Scotland where there is a rich maritime history and an abundance of wrecks to be explored. He has a passion for project diving and is developing objectives for a number of sites with the GUE Scotland team. He hopes to assist on the Mars Project and with the WKPP in the future.

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