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Surviving an Uncontrolled Ascent

What do you do when your power inflator sticks open at depth, you’re unable to disconnect it, and unable to reach your right post to shut it down because of an overinflated wing? That’s the question tech diver Maureen Roberts found herself grappling with as she began accelerating towards the surface 26 m/120 f above.



By Maureen Roberts
Header image courtesy of Julian Mühlenhaus

On Saturday, September 11, 2021, I was on a shore diving trip with friends in Carmel-By-The-Sea, California, when I experienced a runaway power inflator and an uncontrolled ascent to the surface on a technical dive.  

I finished my Global Underwater Explorers (GUE) Technical Diver 1 course in December 2019, but didn’t dive much during the first part of the pandemic.  Now vaccinated, I was diving again, but I still only had 18 tech dives.  I took the GUE DPV Diver 1 course in May 2021, and had 20 scooter dives by the time of the trip.  

Photo by Keith Chu

We planned to do tech dives using diver propulsion vehicles (DPVs) at Point Lobos in a team of three. Our first dive would be a scooter run out to Montana, max depth of 46 m/150 ft, and the 2nd dive to Beto’s reef, max depth of 36 m/120 ft. We discussed the need to avoid surfacing at the deeper parts of the dive if we became separated, due to surface currents in that area. The plan was to scooter back to shallower depths and the protection of the cove before surfacing.  

We exited the water in high spirits after the first dive. We had some lunch and then got ready for the second dive.  On the second dive, I was Diver #3, and Diver #1 was navigating. We planned for an average depth of 30 m/100 ft and a maximum depth 46 m/120 ft and decompression on 100% oxygen (O2).  

The first part of the dive was uneventful and picturesque.  We were treated to about 15 m/50 ft visibility and a lot of different marine life than we usually see in southern California (SoCal). I was happy to see so many varieties of starfish, which have become rare in SoCal.  As we reached the farthest point out on our dive, 29 minutes runtime, I fell about 3 m/10 ft behind Divers #1 and 2, who were wing on wing.  I had just looked at my dive computer, and I saw our depth at 46 m/120 ft, and a deco time of one minute.  

I was adjusting buoyancy, and added a little gas to my wing. When I pressed the inflator, it gave a wimpy puff, almost like I’d pressurized my regs and then turned them off during a pre-dive check, and puffed the last little bit of gas into the wing.  I added a puff of gas to my drysuit to alleviate some squeeze, then returned to the wing inflator, thinking, “Hmm.”  As I pressed it, the button stuck down and my wing began to rapidly inflate.  

It All Looks Up To Me

For a few seconds, I tried to unstick the inflator button, but it didn’t budge. I reached for my right valve with my right hand (dropping the scooter handle) and my butt dump with my left hand. I felt myself rising and I realized I could not reach the right post because my wing was so full. My wing’s overpressurization relief valve (OPV) started to dump and bubbles began to obscure my vision. The other divers were now about 6 m/20 ft away, and I was rising above them. I screamed to them through my regulator, but we were all wearing hoods in the cold water, and that plus the hum of their scooters drowned me out.  

The gas in my drysuit was expanding as I ascended, and I went to a more vertical position of about 45 degrees and vented my drysuit while I tried to disconnect the inflator hose. I wasn’t able to disconnect it. My hands were cold and I was wearing dry gloves with thick undergloves.  At that point, I had risen about 6-9 m/20-30 ft, and I was accelerating. I had gone from “What is happening?” to “I will handle this,” to “Oh my God, I’m going to the surface!” in just a few seconds. I reached back again, trying to get to the right post, but my wing was very full, it was impossible to turn the valve, and I was starting to feel squeezed by the wing.  

As my drysuit inflated, I even tried to claw open the neck seal to flood it, but I couldn’t get my fingers underneath my hood. I had a brief moment of wondering if this was going to be how I die, but my brain was constantly telling me to try something else as each thing didn’t work.

My vision was now completely obscured by bubbles from the wing’s OPV, so I could not tell if my teammates saw what was happening. I suspected they had not. Then it became very bright, and I was on the surface. The entire ascent lasted only 90 seconds.

My wing was still massively inflated, squeezing me and dumping out the OPV. I couldn’t reach the right valve on the surface, either. I tried again to get the inflator hose disconnected, but I couldn’t. Simultaneously, I was trying to get my bearings toward the shore. I had surfaced at the exact farthest point of our dive. The thought of the currents we had discussed crossed my mind. I squirmed around trying to get the right post shut off, while I studied the shoreline to make sure I knew where I was. I wanted to try to descend again, but I couldn’t get the wing to stop inflating. I switched to my 100% O2 and clipped off my primary regulator. 

After a few minutes of struggling, I was finally able to simultaneously dump the wing and roll the post off by degrees until it was off. Then I was thankful to dump some of the gas from my wing and relieve the squeeze it was putting on my chest. I was surprised to find I still had 2000 psi/138 bar in my double 100s/12 liter. I had about 2500 psi/172 bar when my ascent began.  

At that point, more than five minutes had elapsed, and I was not sure whether to descend or not. I looked at my computer, noted the 93% surface gradient, and that it said rapid ascent and missed deco stop. I realized that I had more of a rapid ascent than missed deco, and given that and the length of time already on the surface, I decided not to descend. I kept taking a mental inventory of myself and looking for anything wrong, but I felt physically okay, just a bit shaken up. I told myself, “You are okay” a few times.  I wanted to be out of the water, though.

I started to scooter toward the entry point, and for a while I couldn’t tell if I was making progress. I didn’t want to have to be rescued. I decided to scooter until my batteries died, and if I didn’t make it in, then I would go to Plan B. I have a personal locator beacon (PLB) on my harness. I hoped I wouldn’t need it. I should have inflated my diver surface marker buoy (DSMB), but I honestly didn’t think of it. At that point, I didn’t want to summon anyone from shore, yet. But it could have helped my teammates see me if they were on the surface, even though the ocean was relatively flat.

Finally, I could see that I was making progress to shore, despite whatever surface current there was. I felt relief and wondered what my teammates were doing. Had they already exited ahead of me? I didn’t think so, because I didn’t see any commotion on shore. I assumed if they got out without me, the people on shore would have looked like they were looking for someone in the water.

Toward the exit, there was thick kelp on the surface and I made the mistake of heading into it rather than taking a circuitous route. I stopped and had to disentangle myself a couple of times, and then I finally decided to descend to about 1.5 m/5 ft to get through. I was aware of the need not to struggle or exert myself. 

The Aftermath

Once I got through the kelp and onto the exit ramp, I saw some of my friends there, hanging out after their dives. One of them, not initially realizing there was a problem, came to help me with my deco bottle and DPV. I slowly removed my fins and started to walk out, wondering how to explain myself.  I said, “I’m not okay, I had a rapid ascent, can you bring the O2 to me, and can someone look for the other divers?”  

Photo by Jennifer Kim

I sat on a bench and someone brought my O2, which I breathed on and off as I described what happened. Someone else brought me some water, and I drank that and tried to be calm. I was now very anxious to see my teammates. I knew that being together, they were probably fine, but I just wanted to see them. Some of my friends went to look for them over the cliffs, and some awkwardly wandered around, loading their cars or checking gear. A couple of people asked if I was experiencing any physical symptoms. I said no. 

Suddenly, I was all by myself on the bench with my O2 and some water, and I felt very alone and just drained. I wished someone would sit next to me and maybe just put a hand on my arm. I kept thinking how, if that had occurred later in the dive or on the first dive, I could have been badly bent or killed. I wondered if I would ever dive again. I kept remembering the exact moment that I realized I was going to the surface, and the fear that I felt, and how I screamed for my teammates but they did not hear me.

After what seemed like a long time, someone said they had spotted the other divers and they were coming in. I could see the ramp and watched my two teammates get out and walk to their cars to gear down. I wondered if they were mad at me. Once they were free of their tanks, they came over and I explained what happened. I was so relieved to see them.

They had looked back, seen that I was missing, and searched for me underwater for 15 minutes, concerned my scooter may have died and I was kicking back to shore, or that I had become lost, or worse. They incurred a deco obligation during the search, and then surfaced closer to shore than I had. Underwater, they had debated whether to surface earlier or to keep looking underwater. Although it seemed like it took me a long time to get squared away and get out of the water, I had already gotten out when they came to the surface.

At that point, I still felt fine, so I continued to breathe my O2 on and off, and my teammates loaded my gear into the car for me. Once we were ready to leave, I called Divers Alert Network (DAN) and told them my story. The startling reality of what I’d just experienced became evident when the DAN volunteer asked me how long since I surfaced and I said “about 20 minutes.” I then noted that my dive computer said 1 hour 33 minutes!  DAN recommended I monitor myself for symptoms but did not recommend I be evaluated at the ER since I felt fine and hadn’t officially missed deco, just had a rapid ascent.

Later, we examined my gear. With the regs pressurized, it was very difficult to disconnect the low pressure (LP) inflator hose, even on land with dry hands. We removed the inflator and the LP hose and replaced both with a new one. 

I had a long talk with my teammates and I called my instructor/mentor. I couldn’t decide whether to dive the following day or not. My teammate, Diver #1, told me to sleep on it. The next morning I decided to do the dive we had planned originally, a 52 m/170 ft tech dive to Twin Peaks. We decided to go in a team of two, starting the dive with another team of three. We agreed we would take things slowly.  

The dive felt fine. I knew once I was in the water that it was the right decision to get back on the proverbial horse. We had a pleasant dive and then I called it a day, waiting in the sun while the others did a second dive.  

Figuring Out What Went Wrong

When we arrived home, I took my malfunctioning inflator to the dive shop to examine it and see if we could determine what went wrong. They serviced my inflator, but it still leaked when we hooked it up to a new hose and tank. I had previously been told, “Don’t service LP inflators, just discard them.” I had ignored that good advice and serviced the LP inflator about 30 dives prior to the incident. It seemed to work fine, until it didn’t. 

After each dive day, I soak my gear in hot water in the bathtub overnight. The LP inflator was about four years old. The hose was about five years old. It just wasn’t a style that was easy to remove when pressurized. I never realized that some LP inflator hoses are easier to remove than others.  Now I have a new, easier-to-remove LP inflator hose and a new power inflator.  

My teammates and I talked about the events of this dive many times over the following days. I will be more diligent in not falling behind when scootering, and if I need the others to slow down for me, I will ask them to.

Photo by Jennifer Kim

Diver #1 and I subsequently went on a skills dive together to practice runaway inflator management. We found that consistently dumping from the butt dump while kicking down, we could arrest the ascent and stabilize in the face of a stuck inflator. Once stabilized, we were able to easily shut the right post off and switch to our backup regulator. Once the right post had been purged, the LP inflator hose was easy to disconnect. I tried a different strategy of going vertical and dumping gas from the corrugated hose while trying to disconnect the LP inflator (rather than using the butt dump and shutting off the right post) but found that I ascended more quickly using that method. I was glad that we practiced the stuck wing inflator because I hadn’t practiced it before. Now I feel confident that I could manage a stuck inflator.

Roberts dive profile

At the time of my incident, I wasn’t as committed to dumping from the OPV as I should have been. Once the OPV started to auto-dump, I didn’t continue to dump it myself. That may have made a difference and given me the ability to dump enough gas to reach the right post.  

We are always told “Stop, breathe, think, act,” but in this case, I didn’t have time to do that. It was “act, act, act, oh no I’m at the surface.”  A lot of the things I did were automatic and I didn’t even think about them.  Some folks have asked me if I could have cut my wing with my knife, or scootered straight down, or kinked off the LP inflator hose. I didn’t have time to think of those things; besides, I had dropped my scooter handle as soon as I tried to reach the right post.

I plan to remember this dive by checking the dates on all my gear every year on September 11. I’m going to start replacing LP inflators annually, and hoses every 3 years.  

I think perhaps the most pragmatic take on the incident was from my T1 teammate (who was not present). When I told him the story, he said “Replace both the inflator and the hose. You’ll be fine, it’s just an incident. Shit happens.” 

Additional Resources:

The Human Diver: The Debrief 

Diver Alert Network: Diving Incident Reporting System

DAN South Africa: One mistake and you are dead – isn’t how accidents normally happen!

Alert A Behind The Scenes Look Into The Making of “Close Calls” 

Forty-four year old Maureen Roberts is an emergency veterinarian based in Pasadena, California and has been diving since 2015. She received her GUE Tech 1 certification in 2019 and her DPV 1 in 2021. She says she likes black jelly beans.

Latest Features


We teamed up with some potty-minded wreckers to explore the poop decks of shipwrecks around the world. Water sports anyone? We offer these heady bits.




In our ongoing search for unusual images, InDepth may have unwittingly uncovered a water-based, closeted fetish among some of the who’s who of wreck diving. I shit you not. 

The fit first hit the shan when we reached out to renowned British wrecker and photographer Leigh Bishop to see if he had any pictures of sunken shipwreck heads. Bishop was a bit dodgy in his email reply. “Just out of curiosity, who else have you asked? Has anyone actually come back and said they have photos of heads?” 


We responded in the affirmative; hyperbaric doc cum wrecker Andrew Fock had indeed sent us a snap depicting a gaggle of sunken thrones from the British warship HMS Hermes. Bishop immediately let loose a missive as if he had been holding it back. “OK,” he replied. “I was just wondering if I wasn’t the ONLY weirdo to have shots of toilets. I do have some, bear with me.” Bishop then dumped NINE images in our box in less time than it took to say “Holy crapper!”  

Once we had Fockie and Bishop in the can, the others followed quickly without raising a stink. Crappy photos started to flow in. We had hit the thunderbox! In fact, shipwreck historian and producer Richie Kohler was one of the few who was obstructed. After complaining about not having a pot to piss in, the inveterate wrecker spilled the beans, “No crappy pix here,” he wrote. “You’re shit outta luck and gonna have to head elsewhere to find a John. Sorry for my potty-mouth. Toodle Loo.” Now that’s a “Dear John” letter!

Our efforts were deeply rewarded when we learned that our late, dear brother, wreck diving pioneer Bart P. Malone (1946-2017) had a thing for honey buckets. A sweet guy, to be sure. Accordingly, we were able to extend a short but heady tribute to the legendary, old-school wrecker, one that he would surely appreciate, as you will soon learn. Thank you Rusty Cassway and Becca Boring for this offering.

The bottom line? You be the judge. We think the shit came out just fine.—M2

Thank you to these heady wreckers for their pics of pots and more; Aron Arngrimssοn, Leigh Bishop, Becca Boring, Jason Brown, Rusty Cassway , Andrew Fock, Gary Gentile, Jesper Kjøller, Chris Kohl, Richie Kohler, Nicolas Lurot, Beto Nava, Pete Mesley, Roger Montero, Erik Petkovic, Becky Kagan Schott, and Tamara Thomsen. Special thanks to John Fitzgerald and Yuko Takegoshi for inspiring the idea.

Header image: A bevy of toilets from the Cypriot cargo ship Yolanda which grounded on a reef at Ras Muhammed in 1980, spilling her cargo. Image from Alamy Ltd.

HMS Hermes

The HMS Hermes was the world’s first purpose built Air Craft Carrier. It was commissioned by the British Royal Navy in 1923 and sunk by the Japanese on April 9, 1942 with the loss of 307 of its crew. Depth (toilets): 44m/145ft. Photo (2010) by Andrew Fock.
Photo by Pete Mesley.

HMNZS Canterbury

HMNZS Canterbury, A New Zealand frigate scuttled in Bay of Islands, New Zealand in 2007. Depth: 31m/103ft. Photos by Pete Mesley.

MS Mikhail Lermontov

MS Mikhail Lermontov, was an Russian Ocean Liner that collided with rocks near Port Gore, New Zealand and sank in 1986. Depth: 28m/94ft. Photos by Pete Mesley.

SV Kingsbridge 

The SV Kingsbridge was an iron hulled clipper ship that sunk after colliding with the sailing ship Candahar with the loss of 15 lives. Depth 90m/295 ft. Photo by Leigh Bishop.

SV Avalanche

SV Avalanche was a three-masted iron sailing ship that sunk in the English Channel in 1877 after colliding with the sailing ship SV Forest, which also sank. Lives lost: 106. Depth: 52m/171ft. Photo by Leigh Bishop.

The SS Egypt

A P&O Liner carrying gold & silver cargo. She sank after a collision in the Celtic Sea. Depth: 127m/417ft. Photo by Leigh Bishop.

Unidentified Paddle Steamer

North Sea. Depth: 50m/164ft. Photo by Leigh Bishop.

SS Tuscania 

The SS Tuscania was a luxury liner that was torpedoed and sunk in 1918 in the Northern Channel between Scotland and Ireland by German U-boat UB-77 while transporting American troops to Europe with the loss of 210 lives. Depth: 102m/335ft. Photo by Leigh Bishop.

SS Justicia

The SS Justiçia was British Troopship that was torpedoed and sunk during WWI near Skerryvore, Scottland. Depth: 70m/229ft. Photo by Leigh Bishop.

Kensho Maru

The Kensho Maru was a passenger cargo ship sunk in Truk Lagoon during Operation Hailstorm in 1944. Depth: 36m/118ftPhoto by Leigh Bishop.

The Oite Destroyer

The Oite Destroyer was a Kamikaze class destroyer sunk in 1944 in Truk Lagoon. Depth: 66m/217ft. Photo by Leigh Bishop.


Katsurigusan Maru was a cargo ship sunk by a Japanese mine in Truk Lagoon in 1944, and is Truk’s deepest shipwreck. Depth: 70m/229ft. Photo by Leigh Bishop.

MS King Cruiser

MS King Cruiser was a car ferry that sank off the West Coast of Southern Thailand on 4 May 1997.  Depth: 24 m/80 f. Photos by Nico Lurot.

SMS Cōln

The SMS Cōln was a light German cruiser scuttled in Scapa Flow at the end of WWI. Depth: 36m/118ft. Photo by Jason Brown,

Aikoku Maru

The Aikoku Maru was an armed merchant cruiser of the Imperial Japanese Navy in World War II. The ship entered service in 1940, and was sunk in February 1944 during Operation Hailstone. Photo by the Dirty Dozen Expeditions.
Photo by Pete Mesley.


Yolanda was a Cypriot cargo ship built in 1964. She was carrying a load of porcelain toilets and bathtubs when she was grounded on a reef at Ras Muhammed in 1980, spilling her cargo. She subsequently slipped off the reef in deep water in 1985 during a storm. Depth: 15m/49 ft. Photos by Jesper Kjøller.

C53 Felipe Xicotencatl

Roger Montero—the “Mayan Diver”—perched on the throne of the C53 Felipe Xicotencatla US Built Admirable-Class minesweeper that was decommissioned in 1999, donated to the Cozumel underwater park and sunk that same year. Depth: 15m/49ft. Photo courtesy of Roger Montero.

SS Andrea Doria

A head on the iconic SS Andrea Doria which sank in July 1956 after a collision with the SS Stockholm off Nantucket Island, Massachusetts, killing 51 people.  Depth (toilet): 58m/190 ft. Photo by Gary Gentile.

USS Wilkes-Barre

USS Wilkes-Barre was a Cleveland-class light cruiser of the US Navy that served during the last year of World War II and was skuttled in 1972. She served as the training wreck for Capt. Billy Deans’ Key West Divers mixed gas classes in the 1990s. Depth: 64m/210 ft. Photo by Gary Gentile.

The SS America

The America was a packet boat transporting passengers, mail, and packages between settlements Isle Royale National Park, Lake Superior, US. Built in 1898, the America sank in Washington Harbor off the shore of Isle Royale in 1928, where the hull still remains. Depth: 24m/80ft. Photo by Tamara Thomsen.

The SS Monarch

The SS Monarch was a passenger-package freighter built in 1890 that operated on the Great Lakes. She was sunk off the shore of Isle Royale in Lake Superior in 1906 and the remains of her wreck and cargo are still on the lake bottom.  Depth: 24m/80ft. Photo by Tamara Thomson.

SS Daniel J Morrell

Rebreather diver explores the captain’s quarters inside the SS Daniel J Morrell, a Great Lakes freighter that broke up in a strong storm on Lake Huron in 1966, taking with it 28 of her 29 crewmen. Depth: 51m/165ft. Photo by Becky Kagan Schott. 

The AA Parker

The AA Parker was a wooden steamship that sank in 1903 during a storm in lake Superior near Grand Marias, Michigan. Notice the bell behind the toilet. Depth: 64m/210ft. Photo by Becky Kagan Schott.

RH Rae

PThe “RH Rae” was a three-masted bark that capsized during a white squall on Lake Ontario in 1958 near Point Traverse. The wreck was explored by the Cousteau in 1980, the only time they ever visited the Great Lakes. Unfortunately, they lost a diver at this site—the only time they had a diving fatality. Depth: 32m/105ft. Photo by Chris Kohl

Shinkoku Maru

The Shinkoku Maru was a Japanese oil tanker that was sunk in Truk Lagoon in 1944 during Operation Hailstone. Below Rusty Cassway pours Bart P. Malone’s  ashes into the Shinkoku Maru head in 2019. Photos by Becca Boring 

Bart P. Malone (1946-2017)

Bart Malone post dive August 2016. Photo by Rusty Cassway

Diving legend Bart P. Malone, who passed away in December, 2017, was an avid collector of shipwreck china. (He was also the co-founder of The Gas Station, the first technical mixed gas station in the Northeast US.) Bart collected ship line china from many of the classic wrecks including the Andrea Doria, SS Carolina and the Empress of Ireland. However, to Bart the quintessential piece of china to obtain was a ships head or toilet.  It was like a giant ceramic bowl. Just bigger.  Bart did this “tongue in cheek”, because as many who knew Bart were aware, he liked to spend a lot of time in the dive boat head prior to and after dives.—Rusty Cassway

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