Presumption is the Mother of Disasters, Part II

This is the second part of our article on errors divers made, thanks to our humble readers who were willing to describe their errors so that others may benefit.

Know What Your Computer Tells You

Too many divers are unfamiliar with their computer displays and assume they always display the remaining No-Stop time. When a computer switches over to the mandated deco-stop mode, it displays what is often unfamiliar information, and some divers ignore that it now displays a downward pointing arrow, indicating they've missed a stop.

Less serious, but still significant, some divers get to a location such as Truk Lagoon, where they might spend longer at depth than they are accustomed to. While they have taken the precaution of carrying a backup computer, they find that the two display different decompression information because they rely on different algorithms.

Of course, divers should use computers with identical algorithms so they have identical backup information. It's surprising how many divers don't realize their computers (such as an Oceanic) provide the option to switch to another algorithm, for example, one similar to Suunto's algorithm. Did the dive store staff fail to mention this when demonstrating its use? Did the diver fail to read the manual carefully? We once wrote about a diver who intentionally left his backup computer behind on a dive because, on the previous dive, it locked him out when it went into the SOS mode. Why use a more conservative computer as backup?

Making one extra dive can mean outstaying your welcome with disastrous consequences. As Mìke Maremesh from Miami (FL), tells us:

"I went to Cocos with Undersea Hunter. On the last day of diving, we did three dives greater than 100-feet, each progressively deeper than the previous. While my Nitrox computer was OK with it, it was obviously the reverse of how we were all taught.

"About an hour after the last dive, l started tingling under the skin around my navel. Trying to be at least semi-smart, l had my dive buddy (my wife) inform the crew. They met me in my cabin just in time to see me black out and keel over unto my bunk. My buddy claims it may have taken a few years off her life. I woke up on O2 and kept on it for the trip back to the mainland. I got checked out by the hyperbaric specialist in San Jose, but I was pretty much back to normal by then. My buddy, who had been wise enough to take it easy and not do the dives, now has even more ammunition to question my judgment.

"Take away. I am not in as good a shape as the much younger dive guide who led the dives, and I am not ashamed to admit it. Sometimes, you need to trust your training and common sense over your computer. It wasn't much consolation that l got a decent video of a 10-foot tiger shark that swam right under me. And it wasn't worth the stress I put my dive buddy through.

Jumping In Without Proper Preparation

A common mistake among cold water divers is jumping in with a drysuit zip that is not entirely closed. A flooded suit is part of the steep learning curve, but contrary to popular beliefs, it doesn't make you heavier in the water, as Chuck Ballenger, a very experienced diver from Mill Valley (CA), found out, and yet it caused serious repercussions. He told Undercurrent that he failed to fully tighten the inner zipper on his DUI drysuit during a trip to dive the wrecks of Scapa Flow in Scotland's Orkney Isles, where the water ranges between 45°F and 55°F.

"Seven of us jumped into four-foot swells frosted with white caps. As we prepared to descend, I realized my drysuit was flooding. I could either cancel my dive or deal with it on the bottom. I decided on the latter and descended to the battleship hull at 100 feet, struggling to close the leaking zipper. To do so, I had to loosen my weight belt enough to open the outer zipper and then tighten the inner zipper. After much effort and almost losing my weights, I realized I couldn't do it. I decided to explore the wreck as long as I could stand the freezing water.

"Hypothermia set in, and I soon couldn't feel or move my legs. I skipped the safety stop and barely made it to the boat. The result: a shoulder bend that later required surgery for bone necrosis."

It's better to forfeit a dive than to risk your health, and Chuck will tell you that.

Your Own Boat Can Be Dangerous

We've often said that a dive boat is the most dangerous thing you encounter diving. Greg White from Cobden (IL) discovered this:

"I'm sure we've all made mistakes that we could look back on and laugh about, but I made one that I still cringe about because, at the time, I thought I had bought the farm. It began with something I thought was a smart idea. It turned out not to be so smart after all.

"Any time that a dive ended under the dive boat, I would stay down at my safety stop depth, waiting until the other divers had exited, then I would kick to the bottom of the ladder, take off my fins underwater, pull myself up the ladder, hand up my fins, and then climb the ladder. This seemed to work well, giving me extra safety stop time and avoiding surface congestion as others floated waiting to exit.

"When it didn't work so well was one day when the seas were really rough. I had just grabbed the bottom of the ladder and taken off one fin when a huge wave lifted the boat and pulled the ladder out of my hand. When the boat came back down, the ladder knocked my mask down my face, which knocked the regulator out of my mouth. There I was with only one fin, my mask around my neck, no air in my BC, and my regulator lost for the time being. My first thought was to inflate my BC, but nothing happened when I pushed the inflate button. Somehow, the low-pressure hose had also come unattached in the process. As I frantically tried to kick to the surface, one of the boat crew fortunately saw me struggling and jumped in to grab me. At about the same time, I managed to find my regulator.

"After that experience, I now ascend completely after each dive, fully inflate my BC on the surface, and make sure I'm ready to climb the ladder before taking off my fins. One near-death experience was enough for me."

David Holzman (Ben Lomond, CA) was in Raja Ampat with friends, all with decades of dive experience in all conditions, enjoying an easy dive following a gradually sloping wall filled with color and fish.

"About halfway through the 60-minute dive, our divemaster signals a change in direction as a current starts to hit us and then increases significantly. We struggled against the current and ascended to eight meters, changed direction again, and drifted with the current over a shallow reef, which soon became our safety stop as the current pushed us at high speed to our pick-up location. However, our boat was moving in the same fast current and was approaching a channel with shallow water.

"Our exit became treacherous as, one by one, we surfaced with our boat in sight but struggling to slow down enough to let each diver ascend the rear-mounted ladder. When my turn came, I saw the ladder flopping up and down on its hinge and realized that I needed to time my grab for the right moment or I'd be battered by the ladder. With all my gear on, I swam behind the boat, grabbed a rung high on the aluminum ladder, and stepped on the bottom rung. The current was moving the boat quickly into the shallow water ahead, and I needed to get up and out as fast as possible so the boat could motor to deeper water. As my full weight started to push the ladder down, I suddenly realized that my fingers were at the ladder's hinge and would be crushed or severed, but I could slide them down just enough to avoid injury. Everything happened so quickly!"

In our October issue, we ran a letter to Undercurrent in which a woman diver described to us how a bouncing ladder had severed her finger.

Odd, Unexpected Things Happen

K.S., a female diver from Cape Town, South Africa, was diving on a liveaboard out of Cairns, NSW. She told us, "I left my tank standing unattended for a moment, and the roll of the boat made it fall over onto my foot, breaking my big toe." Ouch!

Constance Stirling-Engman (Ithaca, NY), had an unusual experience of being unable to submerge using a new hood. "My mistake was diving with a new hood without checking to see if it had an opening to release air. I jumped in and couldn't descend. The hood had filled with air, creating a huge bubblehead, and lifted me just enough so I was stuck at the surface.

"Confused and embarrassed that I was holding everyone up, I returned to the boat, cut several slits in it (it was a lightweight nylon hood), and was able to descend. I could have removed the hood during the first dive, but as a new diver, I wasn't used to problem-solving while in the water. I couldn't figure out how to remove the hood without removing my regulator (that was too scary). If something isn't an emergency, it is good to try to deal with it in the water instead of giving up the dive. These incidents reminded me of the importance of flexible problem-solving during the dive."

Setting the Anchor

After diving at home in California and worldwide since 1975, making a little over 3000 recreational dives, Randy of Palos Verdes Peninsula, CA, has had his share of mistakes, and one we hear about too often: the combination of having no one on board the boat when diving and then failing to set the anchor.

"While learning to operate my newly purchased 25-foot SeaRay, I anchored on the lee side of Ship Rock, a great Catalina Island dive site, and entered the water with my buddy. Unfortunately, the wind shifted while we were underwater (I found out later it usually does), lifting the anchor off the rocks. When we surfaced, my boat was heading back to Two Harbors. Somehow, with all my gear on, I snorkeled to the boat, got in, started her up, and returned to pick up my buddy. Very scary. Another lesson learned the hard way is to check your anchor and know your dive site and prevailing conditions."

Critter Handling

For many divers, it's hard to keep their hands off the animals. Unlike wild animals on land, many creatures underwater are easily approached, and many can be easily touched. Rich Gallagher, once the owner of Marin Scuba Diving (CA), told us, "While diving and photographing in Belize, we encountered a beautiful octopus sitting in the open on a coral outcropping. We gently moved him from place to place for a better image with water in the background or for a close-up. As the fun continued, the gentle creature seemed to settle down and, at one point, rested in my open hand with his tentacles wrapped around my forearm.

"All seemed to be going well until I felt a sharp pain in my wrist and looked down to see a giant stream of green blood gushing from my arm. Octopus have sharp beaks, and this one was tired of putting up with our harassment. I still have the scar as a reminder of my surprise when our gentle friend had had enough."

Says Rich: "It is probably best for divers to avoid direct contact with creatures." And we second that.

Let wildlife be wildlife.

- John Bantin

Next Issue: Our final instalment of unusual mistakes divers have made.