Understand Your Diving Computer

I'm always amazed at divers who do not fully understand their computer displays. I've met plenty on dive trips - computer owners and even more renters - who have never before seen what happens when their computer runs out of no-deco-stop time. There's a disaster waiting, as this story demonstrates.

A young woman in her late thirties from California, an Open Water Diver (and Drysuit Diver) with about 40 dives, traveling by herself, went on her very first liveaboard trip in the Galapagos in July. She shared a cabin aboard the MY Aqua (formerly the Pinguino Explorer), an 80-foot steel-hulled vessel. She (we'll call her "Anna" - not her real name) booked through Blue Water Dive Travel, joining travelers who had booked through other agents. And, the first question arises: Should she have been accepted for booking on such an advanced diving trip, or can any certified diver join? (The story was initially told to Undercurrent by Laurie Holloway, Auburn, MA, her impromptu cabin mate, and we have researched comments from other divers aboard.)

Anna rented her dive equipment aboard the vessel, and since she was inexperienced, she and another diver opted to buddy up with one of the two dive guides. She was diving with nitrox, although she was not yet nitrox-certified.

By the third day of the week, the vessel had made it to the outer islands of Darwin and Wolf, about 150 miles from the main archipelago. It can be a rough trip that takes around 20 hours, and Anna had not slept well during the journey.

Strong currents, big swells, and cold water in the outer islands mean arduous diving. Out of range of a rescue helicopter, it's no place to have a diving accident. After arrival, the diver made a series of four long dives to 90 feet or so, beyond the 60-foot limit for an Open Water Diver certification and possibly invalidating her diving insurance.

After the second dive, Anna complained to Laurie of pain under her left armpit, dismissing it as a pulled muscle. The pain increased after the third dive. After a 40-minute surface interval, she and another diver, together with the guide, a local, took a fourth dive, staying down a little longer than the rest of the group. When they reached the safety stop, both showed their computers to the dive guide; Anna's computer displayed arrows pointing downward and an 18-minute minimum ascent time. But she did not understand what the rented Suunto Zoop computer was telling her. Nor did her companion. Regardless, the guide indicated they all should surface, which they did, missing the mandated deco stops displayed.

Later, the dive guide told them to ignore their computers "because Suunto Zoops were overly conservative." Because he had more than 20 years of experience, they had both bowed to his knowledge. One might suspect that he was more concerned about getting lost at the surface with dusk approaching, being pushed by the strong current toward the reef-top where the Pacific swell was forming breakers.

Regardless, both these divers shoulder the blame for not understanding their computer displays, not taking control of their own deco during the dive, and surrendering their safety to a third person who, most likely, had to make a difficult decision as to the best course of action regarding their safety.

In the panga on the way to the mother ship, Anna wasn't feeling well. Back on board, she took a shower (not a smart action since the hot water can provoke DCS symptoms) before joining the other divers on the aft deck. By this time, she was feeling worse and her left arm had become numb. Laurie insisted that she use the portable therapeutic oxygen set and the dive guides were informed. The other divers attempted to comfort her, some suggesting alternate reasons for the symptoms, such as a pulled muscle and lack of sleep. The crew administered oxygen for 15 minutes at a time with five-minute breaks. She was encouraged to drink water and took aspirin, but her condition worsened, and her right leg became numb. She lost consciousness just as the oxygen set ran out and more had to be decanted from the main supply cylinder.

Laurie went to the wheelhouse, helped herself to the satellite phone, and called DAN. It took some time to connect with a DAN doctor. Apparently, Anna did not have DAN insurance, but Laurie said that DAN was very helpful and told her that the crew needed to initiate the vessel's emergency evacuation plan. They asked for the vessel's phone number so they could call back, but the captain (who spoke no English) had only been aboard for a week and didn't know it. A crew member went to search for the number.

By this time, the casualty's condition had worsened. Skin rashes, a classic symptom of DCS, appeared all over her body. She needed to be medically evacuated and recompressed without delay. But, at Darwin Island, they were 20 hours by boat to the chamber in Santa Cruz.

The MY Aqua departed Darwin as night fell, after arranging that a speedboat complete with a doctor would meet the vessel. Anna was now in excruciating pain, unable to urinate; her legs were without feeling, and she lost control of her bowel. Her eyesight began to fail, and she went in and out of consciousness. The crew continued to administer oxygen, but her condition could hardly be worse.

It took 13 hours to rendezvous with the speedboat at Albemarle Point on Isabela Island. There was no doctor aboard because none had been found at short notice to make the long overnight journey. So, the dive guide accompanied her and continued to administer oxygen.

Carlos Estape, another diver onboard, alleged on Facebook that the crew had told him that MY Aqua only carried sufficient oxygen to treat one diver for six hours at the prescribed rate of 12 liters/minute. He wondered if they had been giving it to Anna at a reduced rate to conserve the supply. (The first rule of using therapeutic oxygen for DCS treatment is to give it soon and give it plenty.) He also posted that he was told that the delay in departing Darwin was because neither the captain nor senior dive guide could deviate from the trip schedule without the express permission of the vessel's owner or its trip operator. The ship also needed permission from the Ecuadorian Navy to travel at night.

When the speedboat arrived at Santiago Island, it was met by a helicopter that transferred the casualty to the hyperbaric chamber in Santa Cruz. Initially, she was treated for six hours, roughly 18 hours after surfacing from her last dive. She may have already been bent on previous dives. She underwent three more sessions and had to wait 10 days before she could fly back to the mainland.

After she had been evacuated, the vessel's second dive guide suggested the remaining passengers could choose either to continue to dive or to end the trip. The passengers sensibly insisted on waiting until the oxygen supplies were reinstated, which they were from another boat before they continued diving.

This second dive guide suggested the incident may have been triggered by a common pre-existing condition, a PFO (patent foramen ovale). According to Benjamin Victor, M.D., Ph.D., certified anatomic pathologist, one in three people have them, which means one in three divers, making them more susceptible to DCS. However, she did not have a PFO. According to Carol Cox (Port St. Joe, FL), another passenger on the boat, she may have suffered from an injury sustained before the trip since she complained of neck pain long before they arrived at Darwin Island.

Regardless, because she didn't know how to use her computer, she exited the water far too early and got bent. Clearly, she and the other diver should have been given proper instruction about their rental computers. And she should have insisted upon it since it was her responsibility to understand it and monitor her dive.

A diver with but 40 dives should not have been diving so deep in such treacherous waters, nor staying longer than no-deco-stop times. In fact, trips to the outer islands of the Galapagos are unsuitable for such an inexperienced diver. Local dive guides may have been diving for 20 years and be very comfortable in the water, but it doesn't necessarily mean they fully understand diving physics or are versed in computer use (as this guide demonstrated). Every individual diver must be fully responsible for her or his dive profile.

Anna's dive companion, who also had the same missed deco his computer required, found that it locked on him for 48 hours, which is a safety measure saying that you violated your profile too much. You must not dive for 48 hours to be safe. Luckily, he showed no discernible DCS symptoms, but still was allowed to make several more dives without a computer, provided he stayed close to the dive guide.

Which, of course, is ridiculous. The only computer that tracks your deco status is the one physically attached to you, especially on a series of dives where plenty of absorbed nitrogen builds up in the body. We hope he avoided DCS, and if he did, he is a lucky man.

Denial by the victim is a common symptom of DCS. Anna felt seasick during the trip out to Darwin and was suffering neck pain before they got there. So, they became the reasons for her discomfort. However, she probably got bent on an earlier dive, dismissing the symptoms and not revealing them to the dive guides.

We learned that a week before this tragic journey, the crew of MY Aqua had lost an outboard motor at Darwin when their panga was overturned trying to pick up a diver who had drifted too close to the enormous waves breaking on the rocky island. This may have weighed heavily on the guide's mind when he decided to risk missing the stops and have everyone surface, regardless of their decompression status. In the balance of risks, he made the wrong decision.

Maybe Laurie Holloway should have known better than to book this boat. She was on board the same boat in the summer of 2020 after it had been laid up thanks to the COVID pandemic. Then, she says, four divers had total regulator failures underwater because detritus within their tanks blocked the valves when they inverted to descend head-first (a technique often necessary in the strong currents). It indicates that there were no debris tubes fitted to the tank valves (as is normal), and the tanks had not been cleaned before being put back into use. Aluminum tanks will produce aluminum oxide powder, while steel tanks may rust inside if allowed to get wet. That's indicative of poor maintenance. Yet Laurie booked a second trip - although it was probably lucky for her cabinmate that she did.

If they were cavalier about tank maintenance, what else aboard was poorly maintained? What about the compressor? The deterioration of the tanks indicates it may have been passing moisture into the tanks. Water in the air from a properly maintained compressor is filtered out as condensate. Make what you will of that.

Since these events, Laurie has been in touch with Anna while she was in Ecuador awaiting a flight back to California. Despite the recompression treatments, she still suffers pain in her chest and difficulty breathing due to a partially collapsed lung. Did barotrauma from a too fast ascent cause this? She remembers little of the two days in the hyperbaric chamber and still has skin rashes. She said the hyperbaric doctor was awesome but is eager for follow-up consultations with both a neurologist and a pulmonary specialist when she gets home. She is still suffering the trauma and trying to make sense of what happened. She was in excellent health before the trip and now doesn't know what the future holds.

Bryan van Leeuwen from the tour operator, Andean Travel Company Cruises, sent out an official statement regarding events. The company admitted there were several aspects that it could improve in its operation, and those improvements were now in progress, including carrying additional oxygen supplies. In the statement he alleges that the guides were unaware of Anna's armpit pain preceding her final dive. They had a rescue plan but protocols to keep the other passengers informed were not good enough. The statement otherwise agrees with the chronology presented above.

So, in summary, a woman booked a trip for which she did not have appropriate diving experience. She ignored the significance of earlier pains. She did not understand or use her rented computer properly. The dive guide chose for her to skip the mandated deco stops rather than risk a difficult pick-up by the panga. And the vessel's crew appeared to the passengers to be inept at dealing with the emergency in such a remote location. It was a catastrophe of errors.

- John Bantin