Diving Log

I just want to say that I am grateful I made this mistake early in my diving experience, rather than later at greater depths and in harsher conditions…

Diving Log

On the final dive on June 9, a combination of factors and inexperience led me to exceed the decompression limit time. During ascent, I did not follow the computer’s decompression-stop instructions.

The Dive

I noticed that my buddy used air much faster than I did. I surfaced with 80–90 bar left after each dive, which made me overconfident. During the last two days, I deliberately stayed slightly deeper than the divemaster, around 19–20 m. Three dives a day had gone smoothly for the first three days; on the last day, at Sipadan, we did four.

Sipadan has a daily visitor quota and is hard to book, so I tried to end each dive with only 30–40 bar to see more. Fighting the current meant the dives were not actually longer than before. On the final Sipadan dive, after swimming around at about 20 m for a while, my computer beeped. I saw a DECO time indicator showing how many minutes remained before the decompression limit. It was very close, but I was swimming against the current and had never encountered this before, so I stayed at the same depth. When the limit was reached, it beeped again, and I ignored it again…

During our three-minute stop at 5 m, I noticed “DECO STOP 3m 12min,” meaning a 12-minute stop at 3 m. Again I failed to understand it and thought things were probably fine. After stopping for about six minutes, I followed the others up. On surfacing, the computer kept alarming, and I suddenly realized I had made a serious mistake. After two minutes of alarms, its No Fly Time and Desaturation Time changed to 48 hours.

Symptoms

Well, six minutes of decompression did not seem too serious. I felt normal after surfacing but was frightened. I searched for information and personal accounts of decompression sickness, canceled the next day’s flight, and started calculating when I would be safe. Six hours later, a rash appeared on my inner thighs, suggesting decompression sickness. From what I had read, however, I had no joint pain, muscle weakness, or other symptoms besides the skin reaction. Nothing else appeared or worsened over the next 24 hours, so I judged it mild and decided to wait and, if possible, seek treatment back in China. I booked a flight after 48 hours. During two flights totaling four hours, the symptoms neither worsened nor improved…

Back in Beijing, I still felt uncertain and visited the hyperbaric oxygen department at the Navy General Hospital. Perhaps because divers are uncommon in China, the doctor seemed even more nervous than I was. After asking about depth, duration, and flight timing, they put me in a hyperbaric chamber for three hours. The chamber simulates pressure at different diving depths while the patient breathes pure oxygen, helping remove nitrogen through oxygen flow. Opening the chamber for just me cost 800 yuan, more than I expected…

Looking Back with Fear

It truly frightened me afterward. I had considered only air consumption, without realizing that four dives a day and extended time at depth could affect the decompression limit. Worse, I was not thinking on that final dive. I had several chances to correct things but missed them because I did not understand my computer. Had I been boat diving or doing deeper AOW dives, the consequences could have been unimaginable. I learned several lessons:

1. Understand every indicator on your dive computer. If something is unusual or unclear, stop the risky behavior, ascend slowly to a safe position, and ask the divemaster.
2. When diving frequently over several days, put safety first and do not try to test your limits.
3. Buy diving insurance…